سند تعریف سازگاری Android 4.0

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ویرایش 4
آخرین به روز رسانی: 21 آوریل 2013

حق نشر © 2012، Google Inc. کلیه حقوق محفوظ است.
compatibility@android.com

فهرست مطالب

1. مقدمه
2. منابع
3. نرم افزار
3.1. سازگاری API مدیریت شده
3.2. سازگاری نرم افزار API
3.3. سازگاری Native API
3.4. سازگاری وب
3.5. سازگاری رفتاری API
3.6. فضاهای نام API
3.7. سازگاری با ماشین مجازی
3.8. سازگاری با رابط کاربری
3.9 مدیریت دستگاه
3.10 دسترسی
3.11 تبدیل متن به گفتار
4. سازگاری بسته بندی برنامه
5. سازگاری چند رسانه ای
6. سازگاری با ابزار توسعه دهنده
7. سازگاری سخت افزار
7.1. نمایشگر و گرافیک
7.2. دستگاه های ورودی
7.3. حسگرها
7.4. اتصال داده
7.5. دوربین ها
7.6. حافظه و ذخیره سازی
7.7. یو اس بی
8. سازگاری با عملکرد
9. سازگاری مدل امنیتی
10. تست سازگاری نرم افزار
11. نرم افزار قابل به روز رسانی
12. تماس با ما
ضمیمه A - روش تست بلوتوث

1. مقدمه

این سند شرایطی را که باید برای سازگاری دستگاه‌ها با Android 4.0 رعایت شود، برشمرده است.

استفاده از "باید"، "نباید"، "لازم"، "باید"، "نباید"، "باید"، "نباید"، "توصیه شده"، "ممکن است" و "اختیاری" طبق استاندارد IETF است. تعریف شده در RFC2119 [ منابع، 1 ].

همانطور که در این سند استفاده می‌شود، «پیاده‌کننده دستگاه» یا «اجراکننده» شخص یا سازمانی است که راه‌حل سخت‌افزار/نرم‌افزاری را با Android 4.0 توسعه می‌دهد. "پیاده سازی دستگاه" یا "پیاده سازی" راه حل سخت افزاری/نرم افزاری است که به این شکل توسعه یافته است.

برای اینکه پیاده‌سازی‌های دستگاه با Android 4.0 سازگار در نظر گرفته شوند، باید الزامات ارائه‌شده در این تعریف سازگاری، از جمله هر سندی که از طریق مرجع گنجانده شده‌اند، داشته باشند.

در مواردی که این تعریف یا تست‌های نرم‌افزاری توضیح داده شده در بخش 10 بی‌صدا، مبهم یا ناقص است، این مسئولیت اجرای دستگاه است که از سازگاری با پیاده‌سازی‌های موجود اطمینان حاصل کند.

به همین دلیل، پروژه منبع باز اندروید [ منابع، 3 ] هم مرجع و هم پیاده سازی ترجیحی اندروید است. پیاده‌سازان دستگاه به شدت تشویق می‌شوند تا پیاده‌سازی‌های خود را تا حد امکان بر اساس کد منبع «بالادست» موجود در پروژه منبع باز Android قرار دهند. در حالی که برخی از مؤلفه‌ها را می‌توان به طور فرضی با پیاده‌سازی‌های جایگزین جایگزین کرد، این عمل به شدت ممنوع است، زیرا گذراندن آزمون‌های نرم‌افزار به طور قابل‌توجهی دشوارتر می‌شود. این مسئولیت پیاده‌کننده است که از سازگاری کامل رفتاری با پیاده‌سازی استاندارد Android، از جمله و فراتر از مجموعه تست سازگاری اطمینان حاصل کند. در نهایت، توجه داشته باشید که تعویض و اصلاح برخی از اجزا به صراحت توسط این سند ممنوع است.

2. منابع

  1. سطوح مورد نیاز IETF RFC2119: http://www.ietf.org/rfc/rfc2119.txt
  2. مروری بر برنامه سازگاری اندروید: http://source.android.com/compatibility/index.html
  3. پروژه متن باز اندروید: http://source.android.com/
  4. تعاریف و مستندات API: http://developer.android.com/reference/packages.html
  5. مرجع مجوزهای Android: http://developer.android.com/reference/android/Manifest.permission.html
  6. مرجع android.os.Build: http://developer.android.com/reference/android/os/Build.html
  7. رشته های نسخه مجاز Android 4.0: http://source.android.com/compatibility/4.0/versions.html
  8. Renderscript: http://developer.android.com/guide/topics/graphics/renderscript.html
  9. شتاب سخت افزار: http://developer.android.com/guide/topics/graphics/hardware-accel.html
  10. کلاس android.webkit.WebView: http://developer.android.com/reference/android/webkit/WebView.html
  11. HTML5: http://www.whatwg.org/specs/web-apps/current-work/multipage/
  12. قابلیت های آفلاین HTML5: http://dev.w3.org/html5/spec/Overview.html#offline
  13. برچسب ویدیوی HTML5: http://dev.w3.org/html5/spec/Overview.html#video
  14. HTML5/W3C geolocation API: http://www.w3.org/TR/geolocation-API/
  15. API پایگاه داده وب HTML5/W3C: http://www.w3.org/TR/webdatabase/
  16. HTML5/W3C IndexedDB API: http://www.w3.org/TR/IndexedDB/
  17. مشخصات ماشین مجازی Dalvik: در کد منبع Android در dalvik/docs موجود است
  18. AppWidgets: http://developer.android.com/guide/practices/ui_guidelines/widget_design.html
  19. اعلان ها: http://developer.android.com/guide/topics/ui/notifiers/notifications.html
  20. منابع برنامه: http://code.google.com/android/reference/available-resources.html
  21. راهنمای سبک نماد نوار وضعیت: http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure
  22. مدیر جستجو: http://developer.android.com/reference/android/app/SearchManager.html
  23. نان تست: http://developer.android.com/reference/android/widget/Toast.html
  24. تم ها: http://developer.android.com/guide/topics/ui/themes.html
  25. کلاس R.style: http://developer.android.com/reference/android/R.style.html
  26. تصاویر پس زمینه زنده: http://developer.android.com/resources/articles/live-wallpapers.html
  27. مدیریت دستگاه Android: http://developer.android.com/guide/topics/admin/device-admin.html
  28. کلاس android.app.admin.DevicePolicyManager: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html
  29. APIهای سرویس دسترس‌پذیری Android: http://developer.android.com/reference/android/accessibilityservice/package-summary.html
  30. APIهای دسترسی Android: http://developer.android.com/reference/android/view/accessibility/package-summary.html
  31. پروژه Eyes Free: http://code.google.com/p/eyes-free
  32. APIهای Text-To-Speech: http://developer.android.com/reference/android/speech/tts/package-summary.html
  33. مستندات ابزار مرجع (برای adb، aapt، ddms): http://developer.android.com/guide/developing/tools/index.html
  34. توضیحات فایل apk اندروید: http://developer.android.com/guide/topics/fundamentals.html
  35. فایل های مانیفست: http://developer.android.com/guide/topics/manifest/manifest-intro.html
  36. ابزار تست میمون: http://developer.android.com/guide/developing/tools/monkey.html
  37. Android android.content.pm.PackageManager کلاس و لیست ویژگی های سخت افزار: http://developer.android.com/reference/android/content/pm/PackageManager.html
  38. پشتیبانی از چند صفحه: http://developer.android.com/guide/practices/screens_support.html
  39. android.util.DisplayMetrics: http://developer.android.com/reference/android/util/DisplayMetrics.html
  40. android.content.res.Configuration: http://developer.android.com/reference/android/content/res/Configuration.html
  41. android.hardware.SensorEvent: http://developer.android.com/reference/android/hardware/SensorEvent.html
  42. API بلوتوث: http://developer.android.com/reference/android/bluetooth/package-summary.html
  43. NDEF Push Protocol: http://source.android.com/compatibility/ndef-push-protocol.pdf
  44. MIFARE MF1S503X: http://www.nxp.com/documents/data_sheet/MF1S503x.pdf
  45. MIFARE MF1S703X: http://www.nxp.com/documents/data_sheet/MF1S703x.pdf
  46. MIFARE MF0ICU1: http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf
  47. MIFARE MF0ICU2: http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf
  48. MIFARE AN130511: http://www.nxp.com/documents/application_note/AN130511.pdf
  49. MIFARE AN130411: http://www.nxp.com/documents/application_note/AN130411.pdf
  50. API جهت‌گیری دوربین: http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)
  51. android.hardware.Camera: http://developer.android.com/reference/android/hardware/Camera.html
  52. لوازم جانبی باز اندروید: http://developer.android.com/guide/topics/usb/accessory.html
  53. USB Host API: http://developer.android.com/guide/topics/usb/host.html
  54. مرجع امنیت و مجوزهای Android: http://developer.android.com/guide/topics/security/security.html
  55. برنامه های اندروید: http://code.google.com/p/apps-for-android
  56. کلاس android.app.DownloadManager: http://developer.android.com/reference/android/app/DownloadManager.html
  57. انتقال فایل اندروید: http://www.android.com/filetransfer
  58. قالب‌های رسانه اندروید: http://developer.android.com/guide/appendix/media-formats.html
  59. پروتکل پیش‌نویس پخش جریانی زنده HTTP: http://tools.ietf.org/html/draft-pantos-http-live-streaming-03
  60. Motion Event API: http://developer.android.com/reference/android/view/MotionEvent.html
  61. پیکربندی ورودی لمسی: http://source.android.com/tech/input/touch-devices.html

بسیاری از این منابع به طور مستقیم یا غیرمستقیم از Android 4.0 SDK مشتق شده اند و از نظر عملکردی با اطلاعات موجود در اسناد آن SDK یکسان خواهند بود. در هر موردی که این تعریف سازگاری یا مجموعه تست سازگاری با مستندات SDK مخالف باشد، اسناد SDK معتبر تلقی می‌شوند. هر گونه جزئیات فنی ارائه شده در مراجع ذکر شده در بالا به عنوان بخشی از این تعریف سازگاری در نظر گرفته می شود.

3. نرم افزار

3.1. سازگاری API مدیریت شده

محیط اجرای مدیریت شده (مبتنی بر دالویک) وسیله اصلی برنامه های اندروید است. رابط برنامه نویسی برنامه اندروید (API) مجموعه ای از رابط های پلتفرم اندروید است که در معرض برنامه های کاربردی در حال اجرا در محیط VM مدیریت شده قرار دارند. پیاده‌سازی‌های دستگاه باید پیاده‌سازی‌های کامل، از جمله همه رفتارهای مستند، هر API مستندی را که توسط Android 4.0 SDK در معرض دید قرار می‌گیرد [ منابع، 4 ] ارائه دهد.

پیاده‌سازی‌های دستگاه نباید هیچ‌یک از APIهای مدیریت‌شده را حذف کنند، رابط‌ها یا امضاهای API را تغییر دهند، از رفتار مستند منحرف شوند، یا شامل موارد بدون عملیات باشند، مگر در مواردی که به‌طور خاص توسط این تعریف سازگاری مجاز است.

این تعریف سازگاری اجازه می‌دهد برخی از انواع سخت‌افزاری که Android برای آن‌ها دارای API است توسط پیاده‌سازی دستگاه حذف شوند. در چنین مواردی، APIها باید همچنان وجود داشته باشند و به روشی معقول رفتار کنند. برای شرایط خاص این سناریو به بخش 7 مراجعه کنید.

3.2. سازگاری نرم افزار API

علاوه بر APIهای مدیریت شده از بخش 3.1، Android همچنین شامل یک API "نرم" فقط زمان اجرا قابل توجه است، به شکل مواردی مانند Intent ها، مجوزها، و جنبه های مشابه برنامه های Android که در زمان کامپایل برنامه قابل اجرا نیستند.

3.2.1. مجوزها

پیاده‌کننده‌های دستگاه باید تمام ثابت‌های مجوز را همانطور که در صفحه مرجع مجوز [ منابع، 5 ] مستند شده است، پشتیبانی و اجرا کنند. توجه داشته باشید که بخش 10 الزامات اضافی مربوط به مدل امنیتی اندروید را فهرست می کند.

3.2.3. ساخت پارامترها

APIهای Android شامل تعدادی ثابت در کلاس android.os.Build [ منابع، 6 ] هستند که برای توصیف دستگاه فعلی در نظر گرفته شده است. برای ارائه مقادیر معنادار و منسجم در بین پیاده‌سازی‌های دستگاه، جدول زیر شامل محدودیت‌های اضافی در قالب‌های این مقادیر است که پیاده‌سازی دستگاه باید با آنها مطابقت داشته باشد.

پارامتر نظرات
android.os.Build.VERSION.RELEASE نسخه سیستم اندروید در حال اجرا، در قالب قابل خواندن توسط انسان. این فیلد باید دارای یکی از مقادیر رشته تعریف شده در [ منابع، 7 ] باشد.
android.os.Build.VERSION.SDK نسخه سیستم Android در حال اجرا، در قالبی که برای کد برنامه شخص ثالث قابل دسترسی است. برای Android 4.0.1 - 4.0.2، این فیلد باید مقدار صحیح 14 را داشته باشد. برای Android 4.0.3 یا بالاتر، این فیلد باید دارای مقدار صحیح 15 ​​باشد.
android.os.Build.VERSION.SDK_INT نسخه سیستم Android در حال اجرا، در قالبی که برای کد برنامه شخص ثالث قابل دسترسی است. برای Android 4.0.1 - 4.0.2، این فیلد باید مقدار صحیح 14 را داشته باشد. برای Android 4.0.3 یا بالاتر، این فیلد باید دارای مقدار صحیح 15 ​​باشد.
android.os.Build.VERSION.INCREMENTAL مقداری که توسط پیاده‌کننده دستگاه انتخاب شده است که ساختار خاص سیستم Android در حال اجرا را در قالب قابل خواندن توسط انسان تعیین می‌کند. این مقدار نباید برای ساخت‌های مختلفی که در دسترس کاربران نهایی قرار گرفته‌اند دوباره استفاده شود. یک استفاده معمولی از این فیلد این است که نشان دهد کدام شماره ساخت یا شناسه تغییر منبع-کنترل برای تولید بیلد استفاده شده است. هیچ الزامی برای قالب خاص این فیلد وجود ندارد، به جز اینکه نباید خالی یا رشته خالی ("") باشد.
android.os.Build.BOARD مقداری که توسط پیاده‌کننده دستگاه انتخاب می‌شود و سخت‌افزار داخلی خاص مورد استفاده دستگاه را در قالب قابل خواندن توسط انسان شناسایی می‌کند. یکی از کاربردهای احتمالی این فیلد نشان دادن بازبینی خاص برد تغذیه کننده دستگاه است. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.BRAND مقداری که توسط پیاده‌کننده دستگاه انتخاب می‌شود و نام شرکت، سازمان، فردی و غیره را که دستگاه را تولید کرده است، در قالب قابل خواندن توسط انسان مشخص می‌کند. استفاده احتمالی از این فیلد نشان دادن OEM و/یا حاملی است که دستگاه را فروخته است. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.CPU_ABI نام مجموعه دستورالعمل (نوع CPU + قرارداد ABI) کد بومی. به بخش 3.3: سازگاری Native API مراجعه کنید.
android.os.Build.CPU_ABI2 نام مجموعه دستورات دوم (نوع CPU + قرارداد ABI) کد بومی. به بخش 3.3: سازگاری Native API مراجعه کنید.
android.os.Build.DEVICE مقداری که توسط پیاده‌کننده دستگاه انتخاب می‌شود و پیکربندی یا بازبینی خاص بدنه (که گاهی «طراحی صنعتی» نامیده می‌شود) دستگاه را مشخص می‌کند. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.FINGERPRINT رشته ای که به طور منحصر به فرد این ساخت را مشخص می کند. باید به طور منطقی برای انسان قابل خواندن باشد. باید از این الگو پیروی کند:
$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)
مثلا:
acme/mydevice/generic:4.0/IRK77/3359:userdebug/test-keys
اثر انگشت نباید شامل کاراکترهای فضای خالی باشد. اگر سایر فیلدهای موجود در الگوی بالا دارای نویسه‌های فضای خالی هستند، آنها باید در اثر انگشت ساخت با نویسه دیگری مانند نویسه زیرخط ("_") جایگزین شوند. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد.
android.os.Build.HARDWARE نام سخت افزار (از خط فرمان هسته یا /proc). باید به طور منطقی برای انسان قابل خواندن باشد. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.HOST رشته ای که به طور منحصر به فرد میزبانی را که ساخت بر روی آن ساخته شده است، در قالب قابل خواندن توسط انسان، شناسایی می کند. هیچ الزامی برای قالب خاص این فیلد وجود ندارد، به جز اینکه نباید خالی یا رشته خالی ("") باشد.
android.os.Build.ID شناسه‌ای که توسط پیاده‌کننده دستگاه برای ارجاع به یک نسخه خاص، در قالب قابل خواندن توسط انسان انتخاب شده است. این فیلد می تواند همان android.os.Build.VERSION.INCREMENTAL باشد، اما باید مقداری باشد که به اندازه کافی معنی دار باشد تا کاربران نهایی بتوانند بین ساخت های نرم افزار تمایز قائل شوند. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.MANUFACTURER نام تجاری سازنده اصلی تجهیزات (OEM) محصول. هیچ الزامی برای قالب خاص این فیلد وجود ندارد، به جز اینکه نباید خالی یا رشته خالی ("") باشد.
android.os.Build.MODEL مقداری که توسط پیاده‌کننده دستگاه انتخاب شده و حاوی نام دستگاهی است که کاربر نهایی آن را می‌شناسد. این باید همان نامی باشد که دستگاه تحت آن به بازار عرضه شده و به کاربران نهایی فروخته می شود. هیچ الزامی برای قالب خاص این فیلد وجود ندارد، به جز اینکه نباید خالی یا رشته خالی ("") باشد.
android.os.Build.PRODUCT مقداری که توسط پیاده‌کننده دستگاه انتخاب می‌شود و حاوی نام توسعه یا کد نام محصول (SKU) است. باید برای انسان قابل خواندن باشد، اما لزوماً برای مشاهده توسط کاربران نهایی در نظر گرفته نشده است. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.SERIAL شماره سریال سخت افزاری، در صورت موجود بودن. مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^([a-zA-Z0-9]{0,20})$" مطابقت داشته باشد.
android.os.Build.TAGS فهرستی از برچسب‌های جدا شده با کاما که توسط پیاده‌کننده دستگاه انتخاب شده‌اند که ساخت را بیشتر متمایز می‌کند. به عنوان مثال، "unsigned, debug". مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.TIME مقداری که نشان‌دهنده مُهر زمانی زمان وقوع ساخت است.
android.os.Build.TYPE مقداری که توسط پیاده‌کننده دستگاه انتخاب شده و پیکربندی زمان اجرا ساخت را مشخص می‌کند. این فیلد باید یکی از مقادیر مربوط به سه پیکربندی معمول زمان اجرا اندروید را داشته باشد: "user"، "userdbug"، یا "eng". مقدار این فیلد باید به صورت ASCII 7 بیتی قابل رمزگذاری باشد و با عبارت منظم "^[a-zA-Z0-9.,_-]+$" .
android.os.Build.USER نام یا شناسه کاربری کاربر (یا کاربر خودکار) که ساخت را ایجاد کرده است. هیچ الزامی برای قالب خاص این فیلد وجود ندارد، به جز اینکه نباید خالی یا رشته خالی ("") باشد.

3.2.3. سازگاری قصد

پیاده‌سازی‌های دستگاه باید از سیستم Intent با اتصال شل، همانطور که در بخش‌های زیر توضیح داده شده است، احترام بگذارند. منظور از "honored" این است که پیاده‌کننده دستگاه باید یک فعالیت یا سرویس Android ارائه دهد که فیلتر Intent منطبق را مشخص می‌کند و به هر الگوی Intent مشخص شده متصل می‌شود و رفتار صحیح را اجرا می‌کند.

3.2.3.1. اهداف اصلی برنامه

پروژه upstream اندروید تعدادی برنامه اصلی مانند مخاطبین، تقویم، گالری عکس، پخش کننده موسیقی و غیره را تعریف می کند. پیاده‌کننده‌های دستگاه ممکن است این برنامه‌ها را با نسخه‌های جایگزین جایگزین کنند.

با این حال، هر گونه نسخه جایگزین باید از همان الگوهای Intent ارائه شده توسط پروژه بالادستی استفاده کند. به عنوان مثال، اگر دستگاهی حاوی یک پخش کننده موسیقی جایگزین باشد، همچنان باید الگوی Intent صادر شده توسط برنامه های شخص ثالث را برای انتخاب آهنگ رعایت کند.

برنامه های زیر به عنوان برنامه های اصلی سیستم اندروید در نظر گرفته می شوند:

  • ساعت رومیزی
  • مرورگر
  • تقویم
  • مخاطب
  • گالری
  • جستجوی جهانی
  • پرتاب کننده
  • موسیقی
  • تنظیمات

برنامه های اصلی سیستم اندروید شامل اجزای مختلف Activity یا Service هستند که "عمومی" در نظر گرفته می شوند. به این معنی که ویژگی "android:exported" ممکن است وجود نداشته باشد یا مقدار "true" را داشته باشد.

برای هر فعالیت یا سرویسی که در یکی از برنامه‌های اصلی سیستم Android تعریف شده است و از طریق ویژگی android:exported با مقدار "false" به‌عنوان غیرعمومی علامت‌گذاری نشده است، پیاده‌سازی دستگاه باید شامل یک مولفه از همان نوع باشد که فیلتر Intent یکسان را اجرا می‌کند. الگوها به عنوان برنامه اصلی سیستم اندروید.

به عبارت دیگر، پیاده سازی دستگاه ممکن است جایگزین برنامه های اصلی سیستم اندروید شود. با این حال، اگر چنین باشد، پیاده‌سازی دستگاه باید از همه الگوهای Intent که توسط هر برنامه اصلی سیستم اندرویدی که جایگزین می‌شود، پشتیبانی کند.

3.2.3.2. نادیده گرفتن قصد

از آنجایی که Android یک پلتفرم توسعه‌پذیر است، پیاده‌سازی دستگاه باید به هر الگوی Intent اشاره‌شده در بخش 3.2.3.2 اجازه دهد که توسط برنامه‌های شخص ثالث لغو شود. اجرای متن باز اندروید بالادستی به طور پیش فرض این امکان را می دهد. پیاده‌کننده‌های دستگاه نباید امتیازات ویژه‌ای را به استفاده برنامه‌های سیستمی از این الگوهای Intent اختصاص دهند یا از اتصال برنامه‌های شخص ثالث به این الگوها و کنترل آن‌ها جلوگیری کنند. این ممنوعیت به طور خاص شامل غیرفعال کردن رابط کاربری "انتخاب کننده" است که به کاربر اجازه می دهد بین برنامه های متعددی که همه یک الگوی Intent را مدیریت می کنند، انتخاب کند، اما محدود به آن نمی شود.

3.2.3.3. Intent Namespaces

پیاده‌سازی‌های دستگاه نباید شامل هیچ مؤلفه Android باشد که با استفاده از ACTION، CATEGORY یا رشته‌های کلیدی دیگر در فضای نام android.* یا com.android.*، از الگوهای Intent یا Broadcast Intent جدید استفاده می‌کند. پیاده‌کننده‌های دستگاه نباید دارای اجزای Android باشند که از الگوهای Intent یا Broadcast Intent با استفاده از ACTION، CATEGORY یا رشته‌های کلیدی دیگر در فضای بسته متعلق به سازمان دیگری استفاده می‌کنند. پیاده‌کننده‌های دستگاه نباید هیچ یک از الگوهای Intent را که توسط برنامه‌های اصلی فهرست‌شده در بخش 3.2.3.1 استفاده می‌شود، تغییر داده یا گسترش دهند. پیاده‌سازی‌های دستگاه ممکن است شامل الگوهای Intent با استفاده از فضاهای نام به وضوح و واضح با سازمان خود باشد.

این ممنوعیت مشابه آن چیزی است که برای کلاس های زبان جاوا در بخش 3.6 مشخص شده است.

3.2.3.4. اهداف پخش

برنامه های شخص ثالث برای پخش Intent های خاص به پلتفرم متکی هستند تا تغییرات در محیط سخت افزاری یا نرم افزاری را به آنها اطلاع دهند. دستگاه های سازگار با Android باید Intent های پخش عمومی را در پاسخ به رویدادهای سیستم مناسب پخش کنند. اهداف پخش در مستندات SDK توضیح داده شده است.

3.3. سازگاری Native API

3.3.1 رابط های باینری برنامه

کدهای مدیریت شده در حال اجرا در Dalvik می توانند به کد بومی ارائه شده در فایل apk برنامه کاربردی به عنوان یک فایل ELF .so که برای معماری سخت افزاری مناسب دستگاه کامپایل شده است فراخوانی کند. از آنجایی که کد بومی به شدت به فناوری پردازنده اصلی وابسته است، Android تعدادی رابط باینری برنامه (ABI) را در Android NDK در فایل docs/CPU-ARCH-ABIS.txt . اگر پیاده‌سازی دستگاه با یک یا چند ABI تعریف‌شده سازگار باشد، باید مطابق زیر با Android NDK سازگاری داشته باشد.

اگر پیاده سازی دستگاه شامل پشتیبانی از Android ABI باشد، این موارد:

  • باید شامل پشتیبانی از کدهای در حال اجرا در محیط مدیریت شده برای فراخوانی کد بومی، با استفاده از معناشناسی استاندارد Java Native Interface (JNI) باشد.
  • باید با منبع سازگار (یعنی سازگار با هدر) و سازگار با دودویی (برای ABI) با هر کتابخانه مورد نیاز در لیست زیر باشد.
  • باید به طور دقیق رابط باینری برنامه (ABI) پشتیبانی شده توسط دستگاه را از طریق android.os.Build.CPU_ABI API گزارش کند.
  • باید فقط آن دسته از ABI های مستند شده در آخرین نسخه Android NDK را در فایل docs/CPU-ARCH-ABIS.txt
  • باید با استفاده از کد منبع و فایل‌های هدر موجود در پروژه منبع باز اندروید بالادست ساخته شود

APIهای کد اصلی زیر باید برای برنامه‌هایی که شامل کد بومی هستند در دسترس باشند:

  • libc (کتابخانه C)
  • libm (کتابخانه ریاضی)
  • حداقل پشتیبانی از C++
  • رابط JNI
  • liblog (لاگ اندروید)
  • libz (فشرده سازی Zlib)
  • libdl (پیوند دهنده پویا)
  • libGLESv1_CM.so (OpenGL ES 1.0)
  • libGLESv2.so (OpenGL ES 2.0)
  • libEGL.so (مدیریت سطح OpenGL بومی)
  • libjnigraphics.so
  • libOpenSLES.so (پشتیبانی صوتی OpenSL ES 1.0.1)
  • libOpenMAXAL.so (پشتیبانی از OpenMAX AL 1.0.1)
  • libandroid.so (پشتیبانی از فعالیت های Android بومی)
  • پشتیبانی از OpenGL، همانطور که در زیر توضیح داده شده است

توجه داشته باشید که نسخه‌های بعدی Android NDK ممکن است از ABI‌های اضافی پشتیبانی کند. اگر پیاده سازی دستگاه با ABI از پیش تعریف شده موجود سازگار نباشد، اصلاً نباید پشتیبانی از هیچ ABI را گزارش کند.

سازگاری کد بومی چالش برانگیز است. به همین دلیل، باید تکرار شود که پیاده‌کننده‌های دستگاه به شدت تشویق می‌شوند تا از پیاده‌سازی‌های بالادستی کتابخانه‌های فهرست‌شده در بالا برای اطمینان از سازگاری استفاده کنند.

3.4. سازگاری وب

3.4.1. سازگاری WebView

اجرای متن باز Android از موتور رندر WebKit برای پیاده سازی android.webkit.WebView استفاده می کند. از آنجایی که امکان توسعه یک مجموعه آزمایشی جامع برای یک سیستم رندر وب وجود ندارد، پیاده‌کنندگان دستگاه باید از ساخت بالادستی خاص WebKit در پیاده‌سازی WebView استفاده کنند. به طور مشخص:

  • اجرای پیاده‌سازی‌های دستگاه android.webkit.WebView باید بر اساس ساخت WebKit 534.30 از درخت متن باز Android برای Android 4.0 باشد. این ساخت شامل مجموعه خاصی از عملکردها و اصلاحات امنیتی برای WebView است. پیاده‌کننده‌های دستگاه ممکن است سفارشی‌سازی‌هایی را برای پیاده‌سازی WebKit داشته باشند. با این حال، هر گونه سفارشی سازی نباید رفتار WebView، از جمله رفتار رندر را تغییر دهد.
  • رشته عامل کاربر گزارش شده توسط WebView باید در این قالب باشد:
    Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30
    • مقدار رشته $(VERSION) باید با مقدار android.os.Build.VERSION.RELEASE یکسان باشد.
    • مقدار رشته $(LOCALE) باید از قوانین ISO برای کد کشور و زبان پیروی کند و باید به محلی پیکربندی شده فعلی دستگاه اشاره کند.
    • مقدار رشته $(MODEL) باید با مقدار android.os.Build.MODEL یکسان باشد.
    • مقدار رشته $(BUILD) باید با مقدار android.os.Build.ID یکسان باشد.

مؤلفه WebView باید تا حد امکان از HTML5 پشتیبانی کند [ منابع، 11 ]. حداقل، پیاده سازی دستگاه باید از هر یک از این API های مرتبط با HTML5 در WebView پشتیبانی کند:

به‌علاوه، پیاده‌سازی‌های دستگاه باید از API ذخیره‌سازی وب HTML5/W3C [ منابع، 15 ] پشتیبانی کنند، و باید از HTML5/W3C IndexedDB API [ منابع، 16 ] پشتیبانی کنند. توجه داشته باشید که از آنجایی که نهادهای استاندارد توسعه وب در حال انتقال به سمت ترجیح IndexedDB بر ذخیره‌سازی وب هستند، انتظار می‌رود که IndexedDB به یک جزء ضروری در نسخه آینده اندروید تبدیل شود.

APIهای HTML5، مانند همه APIهای جاوا اسکریپت، باید به طور پیش‌فرض در WebView غیرفعال شوند، مگر اینکه توسعه‌دهنده صریحاً آنها را از طریق APIهای معمول Android فعال کند.

3.4.2. سازگاری مرورگر

پیاده سازی دستگاه باید شامل یک برنامه مرورگر مستقل برای مرور وب کاربر عمومی باشد. ممکن است مرورگر مستقل مبتنی بر فناوری مرورگری غیر از WebKit باشد. با این حال، حتی اگر یک برنامه مرورگر جایگزین استفاده شود، مؤلفه android.webkit.WebView ارائه شده به برنامه های شخص ثالث باید بر اساس WebKit باشد، همانطور که در بخش 3.4.1 توضیح داده شد.

پیاده سازی ها ممکن است یک رشته عامل کاربر سفارشی را در برنامه مرورگر مستقل ارسال کنند.

برنامه مرورگر مستقل (چه بر اساس برنامه بالادستی مرورگر WebKit یا یک جایگزین شخص ثالث) باید تا حد امکان از HTML5 پشتیبانی کند [ منابع، 11 ]. حداقل، پیاده سازی دستگاه باید از هر یک از این API های مرتبط با HTML5 پشتیبانی کند:

به‌علاوه، پیاده‌سازی‌های دستگاه باید از API ذخیره‌سازی وب HTML5/W3C [ منابع، 15 ] پشتیبانی کنند، و باید از HTML5/W3C IndexedDB API [ منابع، 16 ] پشتیبانی کنند. توجه داشته باشید که از آنجایی که نهادهای استاندارد توسعه وب در حال انتقال به سمت ترجیح IndexedDB بر ذخیره‌سازی وب هستند، انتظار می‌رود که IndexedDB به یک جزء ضروری در نسخه آینده اندروید تبدیل شود.

3.5. سازگاری رفتاری API

رفتارهای هر یک از انواع API (مدیریت شده، نرم، بومی و وب) باید با اجرای ترجیحی پروژه منبع باز Android بالادستی مطابقت داشته باشد [ Resources, 3 ]. برخی از زمینه های خاص سازگاری عبارتند از:

  • دستگاه ها نباید رفتار یا معنای یک Intent استاندارد را تغییر دهند
  • دستگاه ها نباید چرخه عمر یا چرخه حیات معنایی نوع خاصی از اجزای سیستم (مانند سرویس، فعالیت، ارائه دهنده محتوا و غیره) را تغییر دهند.
  • دستگاه ها نباید معنای یک مجوز استاندارد را تغییر دهند

لیست فوق جامع نیست. مجموعه تست سازگاری (CTS) بخش های قابل توجهی از پلت فرم را برای سازگاری رفتاری آزمایش می کند، اما نه همه آنها. اطمینان از سازگاری رفتاری با پروژه متن باز اندروید بر عهده مجری است. به همین دلیل، پیاده‌کننده‌های دستگاه باید در صورت امکان از کد منبع موجود از طریق پروژه منبع باز Android استفاده کنند، نه اینکه بخش‌های مهمی از سیستم را دوباره پیاده‌سازی کنند.

3.6. فضاهای نام API

اندروید از قراردادهای فضای نام بسته و کلاس تعریف شده توسط زبان برنامه نویسی جاوا پیروی می کند. برای اطمینان از سازگاری با برنامه‌های شخص ثالث، پیاده‌کننده‌های دستگاه نباید هیچ گونه تغییر ممنوعه (به زیر را ببینید) در این فضاهای نام بسته ایجاد کنند:

  • جاوا.*
  • javax.*
  • آفتاب.*
  • اندروید.*
  • com.android.*

تغییرات ممنوعه عبارتند از:

  • پیاده‌سازی‌های دستگاه نباید با تغییر هر روش یا امضای کلاس، یا با حذف کلاس‌ها یا فیلدهای کلاس، APIهای در معرض عموم در پلتفرم Android را تغییر دهند.
  • پیاده‌کننده‌های دستگاه ممکن است پیاده‌سازی اساسی APIها را تغییر دهند، اما چنین تغییراتی نباید بر رفتار بیان‌شده و امضای زبان جاوا هر یک از API‌های در معرض عموم تأثیر بگذارد.
  • پیاده‌کننده‌های دستگاه نباید هیچ عنصری که به‌صورت عمومی در معرض دید قرار می‌گیرد (مانند کلاس‌ها یا رابط‌ها، یا فیلدها یا روش‌ها به کلاس‌ها یا رابط‌های موجود) به APIهای بالا اضافه کنند.

"عنصر در معرض عموم" هر ساختاری است که با نشانگر "@hide" همانطور که در کد منبع بالادست Android استفاده می شود تزئین نشده باشد. به عبارت دیگر، پیاده‌کننده‌های دستگاه نباید APIهای جدید را افشا کنند یا APIهای موجود را در فضاهای نام ذکر شده در بالا تغییر دهند. پیاده‌کننده‌های دستگاه ممکن است تغییراتی را فقط داخلی انجام دهند، اما این تغییرات نباید تبلیغ شوند یا در معرض دید توسعه‌دهندگان قرار گیرند.

پیاده‌کننده‌های دستگاه ممکن است APIهای سفارشی اضافه کنند، اما چنین API‌هایی نباید در فضای نام متعلق به سازمان دیگری باشند یا به آن ارجاع دهند. برای مثال، پیاده‌کننده‌های دستگاه نباید API را به com.google.* یا فضای نام مشابه اضافه کنند. فقط گوگل می تواند این کار را انجام دهد. به طور مشابه، Google نباید API را به فضای نام شرکت‌های دیگر اضافه کند. علاوه بر این، اگر پیاده‌سازی دستگاه شامل APIهای سفارشی خارج از فضای نام استاندارد Android باشد، آن APIها باید در یک کتابخانه مشترک Android بسته‌بندی شوند تا فقط برنامه‌هایی که به صراحت از آنها استفاده می‌کنند (از طریق مکانیسم <uses-library> ) تحت تأثیر افزایش مصرف حافظه قرار گیرند. از این قبیل APIها

اگر پیاده‌کننده دستگاه پیشنهاد کند یکی از فضاهای نام بسته بالا را بهبود بخشد (مانند افزودن عملکرد مفید جدید به یک API موجود، یا افزودن یک API جدید)، پیاده‌کننده باید از source.android.com بازدید کند و فرآیند ایجاد تغییرات و تغییرات را آغاز کند. کد، با توجه به اطلاعات آن سایت.

توجه داشته باشید که محدودیت‌های بالا با قراردادهای استاندارد برای نام‌گذاری APIها در زبان برنامه‌نویسی جاوا مطابقت دارد. هدف این بخش صرفاً تقویت آن قراردادها و الزام آور ساختن آنها از طریق گنجاندن در این تعریف سازگاری است.

3.7. سازگاری با ماشین مجازی

پیاده سازی دستگاه باید از مشخصات بایت کد کامل Dalvik Executable (DEX) و معناشناسی ماشین مجازی Dalvik [ منابع، 17 ] پشتیبانی کند.

پیاده سازی های دستگاه باید Dalvik را برای تخصیص حافظه مطابق با پلتفرم بالادستی اندروید و همانطور که در جدول زیر مشخص شده است پیکربندی کند. (برای تعاریف اندازه صفحه و تراکم صفحه به بخش 7.1.1 مراجعه کنید.)

توجه داشته باشید که مقادیر حافظه مشخص‌شده در زیر حداقل مقادیر در نظر گرفته می‌شوند و پیاده‌سازی دستگاه ممکن است حافظه بیشتری را به هر برنامه اختصاص دهد.

اندازه صفحه نمایش تراکم صفحه نمایش حافظه برنامه
کوچک / معمولی / بزرگ ldpi / mdpi 16 مگابایت
کوچک / معمولی / بزرگ tvdpi / hdpi 32 مگابایت
کوچک / معمولی / بزرگ xhdpi 64 مگابایت
xlarge mdpi 32MB
xlarge tvdpi / hdpi 64MB
xlarge xhdpi 128MB

3.8. User Interface Compatibility

3.8.1. Widgets

Android defines a component type and corresponding API and lifecycle that allows applications to expose an "AppWidget" to the end user [ Resources, 18 ]. The Android Open Source reference release includes a Launcher application that includes user interface affordances allowing the user to add, view, and remove AppWidgets from the home screen.

Device implementations MAY substitute an alternative to the reference Launcher (ie home screen). Alternative Launchers SHOULD include built-in support for AppWidgets, and expose user interface affordances to add, configure, view, and remove AppWidgets directly within the Launcher. Alternative Launchers MAY omit these user interface elements; however, if they are omitted, the device implementation MUST provide a separate application accessible from the Launcher that allows users to add, configure, view, and remove AppWidgets.

Device implementations MUST be capable of rendering widgets that are 4 x 4 in the standard grid size. (See the App Widget Design Guidelines in the Android SDK documentation [ Resources, 18 ] for details.

3.8.2. Notifications

Android includes APIs that allow developers to notify users of notable events [ Resources, 19 ], using hardware and software features of the device.

Some APIs allow applications to perform notifications or attract attention using hardware, specifically sound, vibration, and light. Device implementations MUST support notifications that use hardware features, as described in the SDK documentation, and to the extent possible with the device implementation hardware. For instance, if a device implementation includes a vibrator, it MUST correctly implement the vibration APIs. If a device implementation lacks hardware, the corresponding APIs MUST be implemented as no-ops. Note that this behavior is further detailed in Section 7.

Additionally, the implementation MUST correctly render all resources (icons, sound files, etc.) provided for in the APIs [ Resources, 20 ], or in the Status/System Bar icon style guide [ Resources, 21 ]. Device implementers MAY provide an alternative user experience for notifications than that provided by the reference Android Open Source implementation; however, such alternative notification systems MUST support existing notification resources, as above.

Android 4.0 includes support for rich notifications, such as interactive Views for ongoing notifications. Device implementations MUST properly display and execute rich notifications, as documented in the Android APIs.

Android includes APIs [ Resources, 22 ] that allow developers to incorporate search into their applications, and expose their application's data into the global system search. Generally speaking, this functionality consists of a single, system-wide user interface that allows users to enter queries, displays suggestions as users type, and displays results. The Android APIs allow developers to reuse this interface to provide search within their own apps, and allow developers to supply results to the common global search user interface.

Device implementations MUST include a single, shared, system-wide search user interface capable of real-time suggestions in response to user input. Device implementations MUST implement the APIs that allow developers to reuse this user interface to provide search within their own applications. Device implementations MUST implement the APIs that allow third-party applications to add suggestions to the search box when it is run in global search mode. If no third-party applications are installed that make use of this functionality, the default behavior SHOULD be to display web search engine results and suggestions.

3.8.4. Toasts

Applications can use the "Toast" API (defined in [ Resources, 23 ]) to display short non-modal strings to the end user, that disappear after a brief period of time. Device implementations MUST display Toasts from applications to end users in some high-visibility manner.

3.8.5. Themes

Android provides "themes" as a mechanism for applications to apply styles across an entire Activity or application. Android 3.0 introduced a new "Holo" or "holographic" theme as a set of defined styles for application developers to use if they want to match the Holo theme look and feel as defined by the Android SDK [ Resources, 24 ]. Device implementations MUST NOT alter any of the Holo theme attributes exposed to applications [ Resources, 25 ].

Android 4.0 introduces a new "Device Default" theme as a set of defined styles for application developers to use if they want to match the look and feel of the device theme as defined by the device implementer. Device implementations MAY modify the DeviceDefault theme attributes exposed to applications [ Resources, 25 ].

3.8.6. Live Wallpapers

Android defines a component type and corresponding API and lifecycle that allows applications to expose one or more "Live Wallpapers" to the end user [ Resources, 26 ]. Live Wallpapers are animations, patterns, or similar images with limited input capabilities that display as a wallpaper, behind other applications.

Hardware is considered capable of reliably running live wallpapers if it can run all live wallpapers, with no limitations on functionality, at a reasonable framerate with no adverse affects on other applications. If limitations in the hardware cause wallpapers and/or applications to crash, malfunction, consume excessive CPU or battery power, or run at unacceptably low frame rates, the hardware is considered incapable of running live wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 context to render their content. Live wallpaper will not run reliably on hardware that does not support multiple OpenGL contexts because the live wallpaper use of an OpenGL context may conflict with other applications that also use an OpenGL context.

Device implementations capable of running live wallpapers reliably as described above SHOULD implement live wallpapers. Device implementations determined to not run live wallpapers reliably as described above MUST NOT implement live wallpapers.

3.8.7. Recent Application Display

The upstream Android 4.0 source code includes a user interface for displaying recent applications using a thumbnail image of the application's graphical state at the moment the user last left the application. Device implementations MAY alter or eliminate this user interface; however, a future version of Android is planned to make more extensive use of this functionality. Device implementations are strongly encouraged to use the upstream Android 4.0 user interface (or a similar thumbnail-based interface) for recent applications, or else they may not be compatible with a future version of Android.

3.8.8. Input Management Settings

Android 4.0 includes support for Input Management Engines. The Android 4.0 APIs allow custom app IMEs to specify user-tunable settings. Device implementations MUST include a way for the user to access IME settings at all times when an IME that provides such user settings is displayed.

3.9 Device Administration

Android 4.0 includes features that allow security-aware applications to perform device administration functions at the system level, such as enforcing password policies or performing remote wipe, through the Android Device Administration API [ Resources, 27 ]. Device implementations MUST provide an implementation of the DevicePolicyManager class [ Resources, 28 ], and SHOULD support the full range of device administration policies defined in the Android SDK documentation [ Resources, 27 ].

If device implementations do not support the full range of device administration policies, they MUST NOT allow device administration applications to be enabled. Specifically, if a device does not support all device administration policies, the device implementation MUST respond to the android.app.admin.DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN intent, but MUST dislpay a message notifying the user that the device does not support device administration.

3.10 Accessibility

Android 4.0 provides an accessibility layer that helps users with disabilities to navigate their devices more easily. In addition, Android 4.0 provides platform APIs that enable accessibility service implementations to receive callbacks for user and system events and generate alternate feedback mechanisms, such as text-to-speech, haptic feedback, and trackball/d-pad navigation [ Resources, 29 ]. Device implementations MUST provide an implementation of the Android accessibility framework consistent with the default Android implementation. Specifically, device implementations MUST meet the following requirements.

  • Device implementations MUST support third party accessibility service implementations through the android.accessibilityservice APIs [ Resources, 30 ].
  • Device implementations MUST generate AccessibilityEvent s and deliver these events to all registered AccessibilityService implementations in a manner consistent with the default Android implementation.
  • Device implementations MUST provide a user-accessible mechanism to enable and disable accessibility services, and MUST display this interface in response to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS intent.

Additionally, device implementations SHOULD provide an implementation of an accessibility service on the device, and SHOULD provide a mechanism for users to enable the accessibility service during device setup. An open source implementation of an accessibility service is available from the Eyes Free project [ Resources, 31 ].

3.11 Text-to-Speech

Android 4.0 includes APIs that allow applications to make use of text-to-speech (TTS) services, and allows service providers to provide implementations of TTS services [ Resources, 32 ]. Device implementations MUST meet these requirements related to the Android TTS framework:

  • Device implementations MUST support the Android TTS framework APIs and SHOULD include a TTS engine supporting the languages available on the device. Note that the upstream Android open source software includes a full-featured TTS engine implementation.
  • Device implementations MUST support installation of third-party TTS engines.
  • Device implementations MUST provide a user-accessible interface that allows users to select a TTS engine for use at the system level.

4. Application Packaging Compatibility

Device implementations MUST install and run Android ".apk" files as generated by the "aapt" tool included in the official Android SDK [ Resources, 33 ].

Devices implementations MUST NOT extend either the .apk [ Resources, 34 ], Android Manifest [ Resources, 35 ], Dalvik bytecode [ Resources, 17 ], or renderscript bytecode formats in such a way that would prevent those files from installing and running correctly on other compatible devices. Device implementers SHOULD use the reference upstream implementation of Dalvik, and the reference implementation's package management system.

5. Multimedia Compatibility

Device implementations MUST include at least one form of audio output, such as speakers, headphone jack, external speaker connection, etc.

5.1. کدک های رسانه ای

Device implementations MUST support the core media formats specified in the Android SDK documentation [ Resources, 58 ] except where explicitly permitted in this document. Specifically, device implementations MUST support the media formats, encoders, decoders, file types and container formats defined in the tables below. All of these codecs are provided as software implementations in the preferred Android implementation from the Android Open Source Project.

Please note that neither Google nor the Open Handset Alliance make any representation that these codecs are unencumbered by third-party patents. Those intending to use this source code in hardware or software products are advised that implementations of this code, including in open source software or shareware, may require patent licenses from the relevant patent holders.

Note that these tables do not list specific bitrate requirements for most video codecs because current device hardware does not necessarily support bitrates that map exactly to the required bitrates specified by the relevant standards. Instead, device implementations SHOULD support the highest bitrate practical on the hardware, up to the limits defined by the specifications.

تایپ کنید Format / Codec Encoder Decoder Details File Type(s) / Container Formats
سمعی AAC LC/LTP REQUIRED
Required for device implementations that include microphone hardware and define android.hardware.microphone .
REQUIRED Mono/Stereo content in any combination of standard bit rates up to 160 kbps and sampling rates from 8 to 48kHz
  • 3GPP (.3gp)
  • MPEG-4 (.mp4, .m4a)
  • ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)
  • MPEG-TS (.ts, not seekable, Android 3.0+)
HE-AACv1 (AAC+) REQUIRED
HE-AACv2 (enhanced AAC+) REQUIRED
AMR-NB REQUIRED
Required for device implementations that include microphone hardware and define android.hardware.microphone .
REQUIRED 4.75 to 12.2 kbps sampled @ 8kHz 3GPP (.3gp)
AMR-WB REQUIRED
Required for device implementations that include microphone hardware and define android.hardware.microphone .
REQUIRED 9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz 3GPP (.3gp)
FLAC REQUIRED
(Android 3.1+)
Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz downsampler does not include a low-pass filter). 16-bit recommended; no dither applied for 24-bit. FLAC (.flac) only
MP3 REQUIRED Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR) MP3 (.mp3)
MIDI REQUIRED MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody
  • Type 0 and 1 (.mid, .xmf, .mxmf)
  • RTTTL/RTX (.rtttl, .rtx)
  • OTA (.ota)
  • iMelody (.imy)
Vorbis REQUIRED
  • Ogg (.ogg)
  • Matroska (.mkv)
PCM/WAVE REQUIRED 8- and 16-bit linear PCM (rates up to limit of hardware) WAVE (.wav)
Image JPEG REQUIRED REQUIRED Base+progressive JPEG (.jpg)
GIF REQUIRED GIF (.gif)
PNG REQUIRED REQUIRED PNG (.png)
BMP REQUIRED BMP (.bmp)
WEBP REQUIRED REQUIRED WebP (.webp)
Video H.263 REQUIRED
Required for device implementations that include camera hardware and define android.hardware.camera or android.hardware.camera.front .
REQUIRED
  • 3GPP (.3gp)
  • MPEG-4 (.mp4)
H.264 AVC REQUIRED
Required for device implementations that include camera hardware and define android.hardware.camera or android.hardware.camera.front .
REQUIRED Baseline Profile (BP)
  • 3GPP (.3gp)
  • MPEG-4 (.mp4)
  • MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)
MPEG-4 SP REQUIRED 3GPP (.3gp)
VP8 REQUIRED
(Android 2.3.3+)
WebM (.webm) and Matroska (.mkv, Android 4.0+)

5.2 Video Encoding

Android device implementations that include a rear-facing camera and declare android.hardware.camera SHOULD support the following video encoding profiles.

SD (Low quality) SD (High quality) HD (When supported by hardware)
Video codec H.264 Baseline Profile H.264 Baseline Profile H.264 Baseline Profile
Video resolution 176 x 144 px 480 x 360 px 1280 x 720 px
Video frame rate 12 fps 30 fps 30 fps
Video bitrate 56 Kbps 500 Kbps or higher 2 Mbps or higher
Audio codec AAC-LC AAC-LC AAC-LC
Audio channels 1 (mono) 2 (stereo) 2 (stereo)
Audio bitrate 24 Kbps 128 Kbps 192 Kbps

5.3. Audio Recording

When an application has used the android.media.AudioRecord API to start recording an audio stream, device implementations that include microphone hardware and declare android.hardware.microphone MUST sample and record audio with each of these behaviors:

  • The device SHOULD exhibit approximately flat amplitude versus frequency characteristics; specifically, ±3 dB, from 100 Hz to 4000 Hz
  • Audio input sensitivity SHOULD be set such that a 90 dB sound power level (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.
  • PCM amplitude levels SHOULD linearly track input SPL changes over at least a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.
  • Total harmonic distortion SHOULD be less than 1% from 100 Hz to 4000 Hz at 90 dB SPL input level.

In addition to the above recording specifications, when an application has started recording an audio stream using the android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:

  • Noise reduction processing, if present, MUST be disabled.
  • Automatic gain control, if present, MUST be disabled.

Note: while some of the requirements outlined above are stated as "SHOULD" for Android 4.0, the Compatibility Definition for a future version is planned to change these to "MUST". That is, these requirements are optional in Android 4.0 but will be required by a future version. Existing and new devices that run Android 4.0 are very strongly encouraged to meet these requirements in Android 4.0 , or they will not be able to attain Android compatibility when upgraded to the future version.

5.4. Audio Latency

Audio latency is broadly defined as the interval between when an application requests an audio playback or record operation, and when the device implementation actually begins the operation. Many classes of applications rely on short latencies, to achieve real-time effects such sound effects or VOIP communication. Device implementations that include microphone hardware and declare android.hardware.microphone SHOULD meet all audio latency requirements outlined in this section. See Section 7 for details on the conditions under which microphone hardware may be omitted by device implementations.

For the purposes of this section:

  • "cold output latency" is defined to be the interval between when an application requests audio playback and when sound begins playing, when the audio system has been idle and powered down prior to the request
  • "warm output latency" is defined to be the interval between when an application requests audio playback and when sound begins playing, when the audio system has been recently used but is currently idle (that is, silent)
  • "continuous output latency" is defined to be the interval between when an application issues a sample to be played and when the speaker physically plays the corresponding sound, while the device is currently playing back audio
  • "cold input latency" is defined to be the interval between when an application requests audio recording and when the first sample is delivered to the application via its callback, when the audio system and microphone has been idle and powered down prior to the request
  • "continuous input latency" is defined to be when an ambient sound occurs and when the sample corresponding to that sound is delivered to a recording application via its callback, while the device is in recording mode

Using the above definitions, device implementations SHOULD exhibit each of these properties:

  • cold output latency of 100 milliseconds or less
  • warm output latency of 10 milliseconds or less
  • continuous output latency of 45 milliseconds or less
  • cold input latency of 100 milliseconds or less
  • continuous input latency of 50 milliseconds or less

Note: while the requirements outlined above are stated as "SHOULD" for Android 4.0, the Compatibility Definition for a future version is planned to change these to "MUST". That is, these requirements are optional in Android 4.0 but will be required by a future version. Existing and new devices that run Android 4.0 are very strongly encouraged to meet these requirements in Android 4.0 , or they will not be able to attain Android compatibility when upgraded to the future version.

If a device implementation meets the requirements of this section, it MAY report support for low-latency audio, by reporting the feature "android.hardware.audio.low-latency" via the android.content.pm.PackageManager class. [ Resources, 37 ] Conversely, if the device implementation does not meet these requirements it MUST NOT report support for low-latency audio.

5.5. Network Protocols

Devices MUST support the media network protocols for audio and video playback as specified in the Android SDK documentation [ Resources, 58 ]. Specifically, devices MUST support the following media network protocols:

  • RTSP (RTP, SDP)
  • HTTP(S) progressive streaming
  • HTTP(S) Live Streaming draft protocol, Version 3 [ Resources, 59 ]

6. Developer Tool Compatibility

Device implementations MUST support the Android Developer Tools provided in the Android SDK. Specifically, Android-compatible devices MUST be compatible with:

  • Android Debug Bridge (known as adb) [ Resources, 33 ]
    Device implementations MUST support all adb functions as documented in the Android SDK. The device-side adb daemon MUST be inactive by default, and there MUST be a user-accessible mechanism to turn on the Android Debug Bridge.
  • Dalvik Debug Monitor Service (known as ddms) [ Resources, 33 ]
    Device implementations MUST support all ddms features as documented in the Android SDK. As ddms uses adb , support for ddms SHOULD be inactive by default, but MUST be supported whenever the user has activated the Android Debug Bridge, as above.
  • Monkey [ Resources, 36 ]
    Device implementations MUST include the Monkey framework, and make it available for applications to use.

Most Linux-based systems and Apple Macintosh systems recognize Android devices using the standard Android SDK tools, without additional support; however Microsoft Windows systems typically require a driver for new Android devices. (For instance, new vendor IDs and sometimes new device IDs require custom USB drivers for Windows systems.) If a device implementation is unrecognized by the adb tool as provided in the standard Android SDK, device implementers MUST provide Windows drivers allowing developers to connect to the device using the adb protocol. These drivers MUST be provided for Windows XP, Windows Vista, and Windows 7, in both 32-bit and 64-bit versions.

7. Hardware Compatibility

If a device includes a particular hardware component that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation. If an API in the SDK interacts with a hardware component that is stated to be optional and the device implementation does not possess that component:

  • complete class definitions (as documented by the SDK) for the component's APIs MUST still be present
  • the API's behaviors MUST be implemented as no-ops in some reasonable fashion
  • API methods MUST return null values where permitted by the SDK documentation
  • API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation
  • API methods MUST NOT throw exceptions not documented by the SDK documentation

A typical example of a scenario where these requirements apply is the telephony API: even on non-phone devices, these APIs must be implemented as reasonable no-ops.

Device implementations MUST accurately report accurate hardware configuration information via the getSystemAvailableFeatures() and hasSystemFeature(String) methods on the android.content.pm.PackageManager class. [ Resources, 37 ]

7.1. Display and Graphics

Android 4.0 includes facilities that automatically adjust application assets and UI layouts appropriately for the device, to ensure that third-party applications run well on a variety of hardware configurations [ Resources, 38 ]. Devices MUST properly implement these APIs and behaviors, as detailed in this section.

The units referenced by the requirements in this section are defined as follows:

  • "Physical diagonal size" is the distance in inches between two opposing corners of the illuminated portion of the display.
  • "dpi" (meaning "dots per inch") is the number of pixels encompassed by a linear horizontal or vertical span of 1". Where dpi values are listed, both horizontal and vertical dpi must fall within the range.
  • "Aspect ratio" is the ratio of the longer dimension of the screen to the shorter dimension. For example, a display of 480x854 pixels would be 854 / 480 = 1.779, or roughly "16:9".
  • A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a 160 dpi screen, calculated as: pixels = dps * (density / 160) .

7.1.1. Screen Configuration

Screen Size

The Android UI framework supports a variety of different screen sizes, and allows applications to query the device screen size (aka "screen layout") via android.content.res.Configuration.screenLayout with the SCREENLAYOUT_SIZE_MASK . Device implementations MUST report the correct screen size as defined in the Android SDK documentation [ Resources, 38 ] and determined by the upstream Android platform. Specifically, device implementations must report the correct screen size according to the following logical density-independent pixel (dp) screen dimensions.

  • Devices MUST have screen sizes of at least 426 dp x 320 dp ('small')
  • Devices that report screen size 'normal' MUST have screen sizes of at least 470 dp x 320 dp
  • Devices that report screen size 'large' MUST have screen sizes of at least 640 dp x 480 dp
  • Devices that report screen size 'xlarge' MUST have screen sizes of at least 960 dp x 720 dp

In addition, devices MUST have screen sizes of at least 2.5 inches in physical diagonal size.

Devices MUST NOT change their reported screen size at any time.

Applications optionally indicate which screen sizes they support via the <supports-screens> attribute in the AndroidManifest.xml file. Device implementations MUST correctly honor applications' stated support for small, normal, large, and xlarge screens, as described in the Android SDK documentation.

Screen Aspect Ratio

The aspect ratio MUST be between 1.3333 (4:3) and 1.85 (16:9).

Screen Density

The Android UI framework defines a set of standard logical densities to help application developers target application resources. Device implementations MUST report one of the following logical Android framework densities through the android.util.DisplayMetrics APIs, and MUST execute applications at this standard density.

  • 120 dpi, known as 'ldpi'
  • 160 dpi, known as 'mdpi'
  • 213 dpi, known as 'tvdpi'
  • 240 dpi, known as 'hdpi'
  • 320 dpi, known as 'xhdpi'
Device implementations SHOULD define the standard Android framework density that is numerically closest to the physical density of the screen, unless that logical density pushes the reported screen size below the minimum supported. If the standard Android framework density that is numerically closest to the physical density results in a screen size that is smaller than the smallest supported compatible screen size (320 dp width), device implementations SHOULD report the next lowest standard Android framework density.

7.1.2. Display Metrics

Device implementations MUST report correct values for all display metrics defined in android.util.DisplayMetrics [ Resources, 39 ].

7.1.3. Screen Orientation

Devices MUST support dynamic orientation by applications to either portrait or landscape screen orientation. That is, the device must respect the application's request for a specific screen orientation. Device implementations MAY select either portrait or landscape orientation as the default.

Devices MUST report the correct value for the device's current orientation, whenever queried via the android.content.res.Configuration.orientation, android.view.Display.getOrientation(), or other APIs.

Devices MUST NOT change the reported screen size or density when changing orientation.

Devices MUST report which screen orientations they support ( android.hardware.screen.portrait and/or android.hardware.screen.landscape ) and MUST report at least one supported orientation. For example, a device with a fixed-orientation landscape screen, such as a television or laptop, MUST only report android.hardware.screen.landscape .

7.1.4. 2D and 3D Graphics Acceleration

Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied and detailed in the Android SDK documentations. Device implementations MUST also support Android Renderscript, as detailed in the Android SDK documentation [ Resources, 8 ].

Device implementations MUST also correctly identify themselves as supporting OpenGL ES 1.0 and 2.0. That is:

  • The managed APIs (such as via the GLES10.getString() method) MUST report support for OpenGL ES 1.0 and 2.0
  • The native C/C++ OpenGL APIs (that is, those available to apps via libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for OpenGL ES 1.0 and 2.0.

Device implementations MAY implement any desired OpenGL ES extensions. However, device implementations MUST report via the OpenGL ES managed and native APIs all extension strings that they do support, and conversely MUST NOT report extension strings that they do not support.

Note that Android 4.0 includes support for applications to optionally specify that they require specific OpenGL texture compression formats. These formats are typically vendor-specific. Device implementations are not required by Android 4.0 to implement any specific texture compression format. However, they SHOULD accurately report any texture compression formats that they do support, via the getString() method in the OpenGL API.

Android 3.0 introduced a mechanism for applications to declare that they wanted to enable hardware acceleration for 2D graphics at the Application, Activity, Window or View level through the use of a manifest tag android:hardwareAccelerated or direct API calls [ Resources, 9 ].

In Android 4.0, device implementations MUST enable hardware acceleration by default, and MUST disable hardware acceleration if the developer so requests by setting android:hardwareAccelerated="false" or disabling hardware acceleration directly through the Android View APIs.

In addition, device implementations MUST exhibit behavior consistent with the Android SDK documentation on hardware acceleration [ Resources, 9 ].

Android 4.0 includes a TextureView object that lets developers directly integrate hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy. Device implementations MUST support the TextureView API, and MUST exhibit consistent behavior with the upstream Android implementation.

7.1.5. Legacy Application Compatibility Mode

Android 4.0 specifies a "compatibility mode" in which the framework operates in an 'normal' screen size equivalent (320dp width) mode for the benefit of legacy applications not developed for old versions of Android that pre-date screen-size independence. Device implementations MUST include support for legacy application compatibility mode as implemented by the upstream Android open source code. That is, device implementations MUST NOT alter the triggers or thresholds at which compatibility mode is activated, and MUST NOT alter the behavior of the compatibility mode itself.

7.1.6. Screen Types

Device implementation screens are classified as one of two types:

  • Fixed-pixel display implementations: the screen is a single panel that supports only a single pixel width and height. Typically the screen is physically integrated with the device. Examples include mobile phones, tablets, and so on.
  • Variable-pixel display implementations: the device implementation either has no embedded screen and includes a video output port such as VGA or HDMI for display, or has an embedded screen that can change pixel dimensions. Examples include televisions, set-top boxes, and so on.

Fixed-Pixel Device Implementations

Fixed-pixel device implementations MAY use screens of any pixel dimensions, provided that they meet the requirements defined this Compatibility Definition.

Fixed-pixel implementations MAY include a video output port for use with an external display. However, if that display is ever used for running apps, the device MUST meet the following requirements:

  • The device MUST report the same screen configuration and display metrics, as detailed in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.
  • The device MUST report the same logical density as the fixed-pixel display.
  • The device MUST report screen dimensions that are the same as, or very close to, the fixed-pixel display.

For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is considered a fixed-pixel large mdpi display implementation. If it contains a video output port that displays at 720p or 1080p, the device implementation MUST scale the output so that applications are only executed in a large mdpi window, regardless of whether the fixed-pixel display or video output port is in use.

Variable-Pixel Device Implementations

Variable-pixel device implementations MUST support one or both of 1280x720, or 1920x1080 (that is, 720p or 1080p). Device implementations with variable-pixel displays MUST NOT support any other screen configuration or mode. Device implementations with variable-pixel screens MAY change screen configuration or mode at runtime or boot-time. For example, a user of a set-top box may replace a 720p display with a 1080p display, and the device implementation may adjust accordingly.

Additionally, variable-pixel device implementations MUST report the following configuration buckets for these pixel dimensions:

  • 1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi) density
  • 1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi) density

For clarity, device implementations with variable pixel dimensions are restricted to 720p or 1080p in Android 4.0, and MUST be configured to report screen size and density buckets as noted above.

7.1.7. Screen Technology

The Android platform includes APIs that allow applications to render rich graphics to the display. Devices MUST support all of these APIs as defined by the Android SDK unless specifically allowed in this document. Specifically:

  • Devices MUST support displays capable of rendering 16-bit color graphics and SHOULD support displays capable of 24-bit color graphics.
  • Devices MUST support displays capable of rendering animations.
  • The display technology used MUST have a pixel aspect ratio (PAR) between 0.9 and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with a 10% tolerance.

7.2. Input Devices

7.2.1. صفحه کلید

Device implementations:

  • MUST include support for the Input Management Framework (which allows third party developers to create Input Management Engines - ie soft keyboard) as detailed at http://developer.android.com
  • MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)
  • MAY include additional soft keyboard implementations
  • MAY include a hardware keyboard
  • MUST NOT include a hardware keyboard that does not match one of the formats specified in android.content.res.Configuration.keyboard [ Resources, 40 ] (that is, QWERTY, or 12-key)

7.2.2. Non-touch Navigation

Device implementations:

  • MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad, or wheel)
  • MUST report the correct value for android.content.res.Configuration.navigation [ Resources, 40 ]
  • MUST provide a reasonable alternative user interface mechanism for the selection and editing of text, compatible with Input Management Engines. The upstream Android open source software includes a selection mechanism suitable for use with devices that lack non-touch navigation inputs.

7.2.3. Navigation keys

The Home, Menu and Back functions are essential to the Android navigation paradigm. Device implementations MUST make these functions available to the user at all times when running applications. These functions MAY be implemented via dedicated physical buttons (such as mechanical or capacitive touch buttons), or MAY be implemented using dedicated software keys, gestures, touch panel, etc. Android 4.0 supports both implementations.

Device implementations MAY use a distinct portion of the screen to display the navigation keys, but if so, MUST meet these requirements:

  • Device implementation navigation keys MUST use a distinct portion of the screen, not available to applications, and MUST NOT obscure or otherwise interfere with the portion of the screen available to applications.
  • Device implementations MUST make available a portion of the display to applications that meets the requirements defined in Section 7.1.1 .
  • Device implementations MUST display the navigation keys when applications do not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE .
  • Device implementations MUST present the navigation keys in an unobtrusive "low profile" (eg. dimmed) mode when applications specify SYSTEM_UI_FLAG_LOW_PROFILE .
  • Device implementations MUST hide the navigation keys when applications specify SYSTEM_UI_FLAG_HIDE_NAVIGATION .
  • Device implementation MUST present a Menu key to applications when targetSdkVersion <= 10 and SHOULD NOT present a Menu key when the targetSdkVersion > 10.

7.2.4. Touchscreen input

Device implementations:

  • MUST have a pointer input system of some kind (either mouse-like, or touch)
  • MAY have a touchscreen of any modality (such as capacitive or resistive)
  • SHOULD support fully independently tracked pointers, if a touchscreen supports multiple pointers
  • MUST report the value of android.content.res.Configuration.touchscreen [ Resources, 40 ] corresponding to the type of the specific touchscreen on the device

Android 4.0 includes support for a variety of touch screens, touch pads, and fake touch input devices. Touch screen based device implementations are associated with a display [ Resources, 61 ] such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen, the system does not require any additional affordances to indicate the objects being manipulated. In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities. For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick, and multi-touch trackpad can support fake touch interactions. Android 4.0 includes the feature constant android.hardware.faketouch , which corresponds to a high-fidelity non-touch (that is, pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in Section 7.2.5 .

Device implementations MUST report the correct feature corresponding to the type of input used. Device implementations that include a touchscreen (single-touch or better) MUST also report the platform feature constant android.hardware.faketouch . Device implementations that do not include a touchscreen (and rely on a pointer device only) MUST NOT report any touchscreen feature, and MUST report only android.hardware.faketouch if they meet the fake touch requirements in Section 7.2.5 .

7.2.5. Fake touch input

Device implementations that declare support for android.hardware.faketouch

  • MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen[ Resources, 60 ]
  • MUST report touch event with the action code [ Resources, 60 ] that specifies the state change that occurs on the pointer going down or up on the screen [ Resources, 60 ]
  • MUST support pointer down and up on an object on the screen, which allows users to emulate tap on an object on the screen
  • MUST support pointer down , pointer up , pointer down then pointer up in the same place on an object on the screen within a time threshold, which allows users to emulate double tap on an object on the screen [ Resources, 60 ]
  • MUST support pointer down on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen, followed by a pointer up , which allows users to emulate a touch drag
  • MUST support pointer down then allow users to quickly move the object to a different position on the screen and then pointer up on the screen, which allows users to fling an object on the screen

Devices that declare support for android.hardware.faketouch.multitouch.distinct MUST meet the requirements for faketouch above, and MUST also support distinct tracking of two or more independent pointer inputs.

7.2.6. Microphone

Device implementations MAY omit a microphone. However, if a device implementation omits a microphone, it MUST NOT report the android.hardware.microphone feature constant, and must implement the audio recording API as no-ops, per Section 7 . Conversely, device implementations that do possess a microphone:

  • MUST report the android.hardware.microphone feature constant
  • SHOULD meet the audio quality requirements in Section 5.3
  • SHOULD meet the audio latency requirements in Section 5.4

7.3. حسگرها

Android 4.0 includes APIs for accessing a variety of sensor types. Devices implementations generally MAY omit these sensors, as provided for in the following subsections. If a device includes a particular sensor type that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation. For example, device implementations:

  • MUST accurately report the presence or absence of sensors per the android.content.pm.PackageManager class. [ Resources, 37 ]
  • MUST return an accurate list of supported sensors via the SensorManager.getSensorList() and similar methods
  • MUST behave reasonably for all other sensor APIs (for example, by returning true or false as appropriate when applications attempt to register listeners, not calling sensor listeners when the corresponding sensors are not present; etc.)
  • MUST report all sensor measurements using the relevant International System of Units (ie metric) values for each sensor type as defined in the Android SDK documentation [ Resources, 41 ]

The list above is not comprehensive; the documented behavior of the Android SDK is to be considered authoritative.

Some sensor types are synthetic, meaning they can be derived from data provided by one or more other sensors. (Examples include the orientation sensor, and the linear acceleration sensor.) Device implementations SHOULD implement these sensor types, when they include the prerequisite physical sensors.

The Android 4.0 APIs introduce a notion of a "streaming" sensor, which is one that returns data continuously, rather than only when the data changes. Device implementations MUST continuously provide periodic data samples for any API indicated by the Android 4.0 SDK documentation to be a streaming sensor.

7.3.1. Accelerometer

Device implementations SHOULD include a 3-axis accelerometer. If a device implementation does include a 3-axis accelerometer, it:

  • MUST be able to deliver events at 50 Hz or greater
  • MUST comply with the Android sensor coordinate system as detailed in the Android APIs (see [ Resources, 41 ])
  • MUST be capable of measuring from freefall up to twice gravity (2g) or more on any three-dimensional vector
  • MUST have 8-bits of accuracy or more
  • MUST have a standard deviation no greater than 0.05 m/s^2

7.3.2. Magnetometer

Device implementations SHOULD include a 3-axis magnetometer (ie compass.) If a device does include a 3-axis magnetometer, it:

  • MUST be able to deliver events at 10 Hz or greater
  • MUST comply with the Android sensor coordinate system as detailed in the Android APIs (see [ Resources, 41 ]).
  • MUST be capable of sampling a range of field strengths adequate to cover the geomagnetic field
  • MUST have 8-bits of accuracy or more
  • MUST have a standard deviation no greater than 0.5 µT

7.3.3. GPS

Device implementations SHOULD include a GPS receiver. If a device implementation does include a GPS receiver, it SHOULD include some form of "assisted GPS" technique to minimize GPS lock-on time.

7.3.4. Gyroscope

Device implementations SHOULD include a gyroscope (ie angular change sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis accelerometer is also included. If a device implementation includes a gyroscope, it:

  • MUST be temperature compensated
  • MUST be capable of measuring orientation changes up to 5.5*Pi radians/second (that is, approximately 1,000 degrees per second)
  • MUST be able to deliver events at 100 Hz or greater
  • MUST have 12-bits of accuracy or more
  • MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s). The variance is allowed to vary with the sampling rate, but must be constrained by this value. In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no greater than 1e-7 rad^2/s^2.
  • MUST have timestamps as close to when the hardware event happened as possible. The constant latency must be removed.

7.3.5. Barometer

Device implementations MAY include a barometer (ie ambient air pressure sensor.) If a device implementation includes a barometer, it:

  • MUST be able to deliver events at 5 Hz or greater
  • MUST have adequate precision to enable estimating altitude

7.3.7. Thermometer

Device implementations MAY but SHOULD NOT include a thermometer (ie temperature sensor.) If a device implementation does include a thermometer, it MUST measure the temperature of the device CPU. It MUST NOT measure any other temperature. (Note that this sensor type is deprecated in the Android 4.0 APIs.)

7.3.7. Photometer

Device implementations MAY include a photometer (ie ambient light sensor.)

7.3.8. Proximity Sensor

Device implementations MAY include a proximity sensor. If a device implementation does include a proximity sensor, it MUST measure the proximity of an object in the same direction as the screen. That is, the proximity sensor MUST be oriented to detect objects close to the screen, as the primary intent of this sensor type is to detect a phone in use by the user. If a device implementation includes a proximity sensor with any other orientation, it MUST NOT be accessible through this API. If a device implementation has a proximity sensor, it MUST be have 1-bit of accuracy or more.

7.4. Data Connectivity

7.4.1. Telephony

"Telephony" as used by the Android 4.0 APIs and this document refers specifically to hardware related to placing voice calls and sending SMS messages via a GSM or CDMA network. While these voice calls may or may not be packet-switched, they are for the purposes of Android 4.0 considered independent of any data connectivity that may be implemented using the same network. In other words, the Android "telephony" functionality and APIs refer specifically to voice calls and SMS; for instance, device implementations that cannot place calls or send/receive SMS messages MUST NOT report the "android.hardware.telephony" feature or any sub-features, regardless of whether they use a cellular network for data connectivity.

Android 4.0 MAY be used on devices that do not include telephony hardware. That is, Android 4.0 is compatible with devices that are not phones. However, if a device implementation does include GSM or CDMA telephony, it MUST implement full support for the API for that technology. Device implementations that do not include telephony hardware MUST implement the full APIs as no-ops.

7.4.2. IEEE 802.11 (WiFi)

Android 4.0 device implementations SHOULD include support for one or more forms of 802.11 (b/g/a/n, etc.) If a device implementation does include support for 802.11, it MUST implement the corresponding Android API.

7.4.3. Bluetooth

Device implementations SHOULD include a Bluetooth transceiver. Device implementations that do include a Bluetooth transceiver MUST enable the RFCOMM-based Bluetooth API as described in the SDK documentation [ Resources, 42 ]. Device implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as appropriate for the device.

The Compatibility Test Suite includes cases that cover basic operation of the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications protocol between devices, it cannot be fully tested by unit tests running on a single device. Consequently, device implementations MUST also pass the human-driven Bluetooth test procedure described in Appendix A.

7.4.4. Near-Field Communications

Device implementations SHOULD include a transceiver and related hardware for Near-Field Communications (NFC). If a device implementation does include NFC hardware, then it:

  • MUST report the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method. [ Resources, 37 ]
  • MUST be capable of reading and writing NDEF messages via the following NFC standards:
    • MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
      • NfcA (ISO14443-3A)
      • NfcB (ISO14443-3B)
      • NfcF (JIS 6319-4)
      • IsoDep (ISO 14443-4)
      • NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
  • SHOULD be capable of reading and writing NDEF messages via the following NFC standards. Note that while the NFC standards below are stated as "SHOULD" for Android 4.0, the Compatibility Definition for a future version is planned to change these to "MUST". That is, these stanards are optional in Android 4.0 but will be required in future versions. Existing and new devices that run Android 4.0 are very strongly encouraged to meet these requirements in Android 4.0 so they will be able to upgrade to the future platform releases.
    • NfcV (ISO 15693)
  • MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
    • ISO 18092
    • LLCP 1.0 (defined by the NFC Forum)
    • SDP 1.0 (defined by the NFC Forum)
    • NDEF Push Protocol [ Resources, 43 ]
    • SNEP 1.0 (defined by the NFC Forum)
  • MUST include support for Android Beam:
    • MUST implement the SNEP default server. Valid NDEF messages received by the default SNEP server MUST be dispatched to applications using the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in settings MUST NOT disable dispatch of incoming NDEF message.
    • MUST implement the NPP server. Messages received by the NPP server MUST be processed the same way as the SNEP default server.
    • MUST implement a SNEP client and attempt to send outbound P2P NDEF to the default SNEP server when Android Beam is enabled. If no default SNEP server is found then the client MUST attempt to send to an NPP server.
    • MUST allow foreground activities to set the outbound P2P NDEF message using android.nfc.NfcAdapter.setNdefPushMessage, and android.nfc.NfcAdapter.setNdefPushMessageCallback, and android.nfc.NfcAdapter.enableForegroundNdefPush.
    • SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', before sending outbound P2P NDEF messages.
    • SHOULD enable Android Beam by default
  • MUST poll for all supported technologies while in NFC discovery mode.
  • SHOULD be in NFC discovery mode while the device is awake with the screen active and the lock-screen unlocked.

(Note that publicly available links are not available for the JIS, ISO, and NFC Forum specifications cited above.)

Additionally, device implementations MAY include reader/writer support for the following MIFARE technologies.

Note that Android 4.0 includes APIs for these MIFARE types. If a device implementation supports MIFARE in the reader/writer role, it:

  • MUST implement the corresponding Android APIs as documented by the Android SDK
  • MUST report the feature com.nxp.mifare from the android.content.pm.PackageManager.hasSystemFeature() method. [ Resources, 37 ] Note that this is not a standard Android feature, and as such does not appear as a constant on the PackageManager class.
  • MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare feature unless it also implements general NFC support as described in this section

If a device implementation does not include NFC hardware, it MUST NOT declare the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 37 ], and MUST implement the Android 4.0 NFC API as a no-op.

As the classes android.nfc.NdefMessage and android.nfc.NdefRecord represent a protocol-independent data representation format, device implementations MUST implement these APIs even if they do not include support for NFC or declare the android.hardware.nfc feature.

7.4.5. Minimum Network Capability

Device implementations MUST include support for one or more forms of data networking. Specifically, device implementations MUST include support for at least one data standard capable of 200Kbit/sec or greater. Examples of technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, Ethernet, etc.

Device implementations where a physical networking standard (such as Ethernet) is the primary data connection SHOULD also include support for at least one common wireless data standard, such as 802.11 (WiFi).

Devices MAY implement more than one form of data connectivity.

7.5. Cameras

Device implementations SHOULD include a rear-facing camera, and MAY include a front-facing camera. A rear-facing camera is a camera located on the side of the device opposite the display; that is, it images scenes on the far side of the device, like a traditional camera. A front-facing camera is a camera located on the same side of the device as the display; that is, a camera typically used to image the user, such as for video conferencing and similar applications.

7.5.1. Rear-Facing Camera

Device implementations SHOULD include a rear-facing camera. If a device implementation includes a rear-facing camera, it:

  • MUST have a resolution of at least 2 megapixels
  • SHOULD have either hardware auto-focus, or software auto-focus implemented in the camera driver (transparent to application software)
  • MAY have fixed-focus or EDOF (extended depth of field) hardware
  • MAY include a flash. If the Camera includes a flash, the flash lamp MUST NOT be lit while an android.hardware.Camera.PreviewCallback instance has been registered on a Camera preview surface, unless the application has explicitly enabled the flash by enabling the FLASH_MODE_AUTO or FLASH_MODE_ON attributes of a Camera.Parameters object. Note that this constraint does not apply to the device's built-in system camera application, but only to third-party applications using Camera.PreviewCallback .

7.5.2. Front-Facing Camera

Device implementations MAY include a front-facing camera. If a device implementation includes a front-facing camera, it:

  • MUST have a resolution of at least VGA (that is, 640x480 pixels)
  • MUST NOT use a front-facing camera as the default for the Camera API. That is, the camera API in Android 4.0 has specific support for front-facing cameras, and device implementations MUST NOT configure the API to to treat a front-facing camera as the default rear-facing camera, even if it is the only camera on the device.
  • MAY include features (such as auto-focus, flash, etc.) available to rear-facing cameras as described in Section 7.5.1.
  • MUST horizontally reflect (ie mirror) the stream displayed by an app in a CameraPreview, as follows:
    • If the device implementation is capable of being rotated by user (such as automatically via an accelerometer or manually via user input), the camera preview MUST be mirrored horizontally relative to the device's current orientation.
    • If the current application has explicitly requested that the Camera display be rotated via a call to the android.hardware.Camera.setDisplayOrientation() [ Resources, 50 ] method, the camera preview MUST be mirrored horizontally relative to the orientation specified by the application.
    • Otherwise, the preview MUST be mirrored along the device's default horizontal axis.
  • MUST mirror the image displayed by the postview in the same manner as the camera preview image stream. (If the device implementation does not support postview, this requirement obviously does not apply.)
  • MUST NOT mirror the final captured still image or video streams returned to application callbacks or committed to media storage

7.5.3. Camera API Behavior

Device implementations MUST implement the following behaviors for the camera-related APIs, for both front- and rear-facing cameras:

  1. If an application has never called android.hardware.Camera.Parameters.setPreviewFormat(int) , then the device MUST use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to application callbacks.
  2. If an application registers an android.hardware.Camera.PreviewCallback instance and the system calls the onPreviewFrame() method when the preview format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() must further be in the NV21 encoding format. That is, NV21 MUST be the default.
  3. Device implementations MUST support the YV12 format (as denoted by the android.graphics.ImageFormat.YV12 constant) for camera previews for both front- and rear-facing cameras. (The hardware video decoder and camera may use any native pixel format, but the device implementation MUST support conversion to YV12.)

Device implementations MUST implement the full Camera API included in the Android 4.0 SDK documentation [ Resources, 51 ]), regardless of whether the device includes hardware autofocus or other capabilities. For instance, cameras that lack autofocus MUST still call any registered android.hardware.Camera.AutoFocusCallback instances (even though this has no relevance to a non-autofocus camera.) Note that this does apply to front-facing cameras; for instance, even though most front-facing cameras do not support autofocus, the API callbacks must still be "faked" as described.

Device implementations MUST recognize and honor each parameter name defined as a constant on the android.hardware.Camera.Parameters class, if the underlying hardware supports the feature. If the device hardware does not support a feature, the API must behave as documented. Conversely, Device implementations MUST NOT honor or recognize string constants passed to the android.hardware.Camera.setParameters() method other than those documented as constants on the android.hardware.Camera.Parameters . That is, device implementations MUST support all standard Camera parameters if the hardware allows, and MUST NOT support custom Camera parameter types.

Device implementations MUST broadcast the Camera.ACTION_NEW_PICTURE intent whenever a new picture is taken by the camera and the entry of the picture has been added to the media store.

Device implementations MUST broadcast the Camera.ACTION_NEW_VIDEO intent whenever a new video is recorded by the camera and the entry of the picture has been added to the media store.

7.5.4. Camera Orientation

Both front- and rear-facing cameras, if present, MUST be oriented so that the long dimension of the camera aligns with the screen's long dimention. That is, when the device is held in the landscape orientation, cameras MUST capture images in the landscape orientation. This applies regardless of the device's natural orientation; that is, it applies to landscape-primary devices as well as portrait-primary devices.

7.6. Memory and Storage

7.6.1. Minimum Memory and Storage

Device implementations MUST have at least 340MB of memory available to the kernel and userspace. The 340MB MUST be in addition to any memory dedicated to hardware components such as radio, video, and so on that is not under the kernel's control.

Device implementations MUST have at least 350MB of non-volatile storage available for application private data. That is, the /data partition MUST be at least 350MB.

The Android APIs include a Download Manager that applications may use to download data files [ Resources, 56 ]. The device implementation of the Download Manager MUST be capable of downloading individual files of at least 100MB in size to the default "cache" location.

7.6.2. Application Shared Storage

Device implementations MUST offer shared storage for applications. The shared storage provided MUST be at least 1GB in size.

Device implementations MUST be configured with shared storage mounted by default, "out of the box". If the shared storage is not mounted on the Linux path /sdcard , then the device MUST include a Linux symbolic link from /sdcard to the actual mount point.

Device implementations MUST enforce as documented the android.permission.WRITE_EXTERNAL_STORAGE permission on this shared storage. Shared storage MUST otherwise be writable by any application that obtains that permission.

Device implementations MAY have hardware for user-accessible removable storage, such as a Secure Digital card. Alternatively, device implementations MAY allocate internal (non-removable) storage as shared storage for apps.

Regardless of the form of shared storage used, device implementations MUST provide some mechanism to access the contents of shared storage from a host computer, such as USB mass storage (UMS) or Media Transfer Protocol (MTP). Device implementations MAY use USB mass storage, but SHOULD use Media Transfer Protocol. If the device implementation supports Media Transfer Protocol:

  • The device implementation SHOULD be compatible with the reference Android MTP host, Android File Transfer [ Resources, 57 ].
  • The device implementation SHOULD report a USB device class of 0x00 .
  • The device implementation SHOULD report a USB interface name of 'MTP'.

If the device implementation lacks USB ports, it MUST provide a host computer with access to the contents of shared storage by some other means, such as a network file system.

It is illustrative to consider two common examples. If a device implementation includes an SD card slot to satisfy the shared storage requirement, a FAT-formatted SD card 1GB in size or larger MUST be included with the device as sold to users, and MUST be mounted by default. Alternatively, if a device implementation uses internal fixed storage to satisfy this requirement, that storage MUST be 1GB in size or larger and mounted on /sdcard (or /sdcard MUST be a symbolic link to the physical location if it is mounted elsewhere.)

Device implementations that include multiple shared storage paths (such as both an SD card slot and shared internal storage) SHOULD modify the core applications such as the media scanner and ContentProvider to transparently support files placed in both locations.

7.7. USB

Device implementations SHOULD include a USB client port, and SHOULD include a USB host port.

If a device implementation includes a USB client port:

  • the port MUST be connectable to a USB host with a standard USB-A port
  • the port SHOULD use the micro USB form factor on the device side
  • it MUST allow a host connected to the device to access the contents of the shared storage volume using either USB mass storage or Media Transfer Protocol
  • it MUST implement the Android Open Accessory API and specification as documented in the Android SDK documentation, and MUST declare support for the hardware feature android.hardware.usb.accessory [ Resources, 51 ]

If a device implementation includes a USB host port:

  • it MAY use a non-standard port form factor, but if so MUST ship with a cable or cables adapting the port to standard USB-A
  • it MUST implement the Android USB host API as documented in the Android SDK, and MUST declare support for the hardware feature android.hardware.usb.host [ Resources, 52 ]

Device implementations MUST implement the Android Debug Bridge. If a device implementation omits a USB client port, it MUST implement the Android Debug Bridge via local-area network (such as Ethernet or 802.11)

8. Performance Compatibility

Device implementations MUST meet the key performance metrics of an Android 4.0 compatible device defined in the table below:

Metric Performance Threshold Comments
Application Launch Time The following applications should launch within the specified time.
  • Browser: less than 1300ms
  • Contacts: less than 700ms
  • Settings: less than 700ms
The launch time is measured as the total time to complete loading the default activity for the application, including the time it takes to start the Linux process, load the Android package into the Dalvik VM, and call onCreate.
Simultaneous Applications When multiple applications have been launched, re-launching an already-running application after it has been launched must take less than the original launch time.

9. Security Model Compatibility

Device implementations MUST implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs [ Resources, 54 ] in the Android developer documentation. Device implementations MUST support installation of self-signed applications without requiring any additional permissions/certificates from any third parties/authorities. Specifically, compatible devices MUST support the security mechanisms described in the follow sub-sections.

9.1. Permissions

Device implementations MUST support the Android permissions model as defined in the Android developer documentation [ Resources, 54 ]. Specifically, implementations MUST enforce each permission defined as described in the SDK documentation; no permissions may be omitted, altered, or ignored. Implementations MAY add additional permissions, provided the new permission ID strings are not in the android.* namespace.

9.2. UID and Process Isolation

Device implementations MUST support the Android application sandbox model, in which each application runs as a unique Unix-style UID and in a separate process. Device implementations MUST support running multiple applications as the same Linux user ID, provided that the applications are properly signed and constructed, as defined in the Security and Permissions reference [ Resources, 54 ].

9.3. Filesystem Permissions

Device implementations MUST support the Android file access permissions model as defined in as defined in the Security and Permissions reference [ Resources, 54 ].

9.4. Alternate Execution Environments

Device implementations MAY include runtime environments that execute applications using some other software or technology than the Dalvik virtual machine or native code. However, such alternate execution environments MUST NOT compromise the Android security model or the security of installed Android applications, as described in this section.

Alternate runtimes MUST themselves be Android applications, and abide by the standard Android security model, as described elsewhere in Section 9.

Alternate runtimes MUST NOT be granted access to resources protected by permissions not requested in the runtime's AndroidManifest.xml file via the <uses-permission> mechanism.

Alternate runtimes MUST NOT permit applications to make use of features protected by Android permissions restricted to system applications.

Alternate runtimes MUST abide by the Android sandbox model. Specifically:

  • Alternate runtimes SHOULD install apps via the PackageManager into separate Android sandboxes (that is, Linux user IDs, etc.)
  • Alternate runtimes MAY provide a single Android sandbox shared by all applications using the alternate runtime.
  • Alternate runtimes and installed applications using an alternate runtime MUST NOT reuse the sandbox of any other app installed on the device, except through the standard Android mechanisms of shared user ID and signing certificate
  • Alternate runtimes MUST NOT launch with, grant, or be granted access to the sandboxes corresponding to other Android applications.

Alternate runtimes MUST NOT be launched with, be granted, or grant to other applications any privileges of the superuser (root), or of any other user ID.

The .apk files of alternate runtimes MAY be included in the system image of a device implementation, but MUST be signed with a key distinct from the key used to sign other applications included with the device implementation.

When installing applications, alternate runtimes MUST obtain user consent for the Android permissions used by the application. That is, if an application needs to make use of a device resource for which there is a corresponding Android permission (such as Camera, GPS, etc.), the alternate runtime MUST inform the user that the application will be able to access that resource. If the runtime environment does not record application capabilities in this manner, the runtime environment MUST list all permissions held by the runtime itself when installing any application using that runtime.

10. Software Compatibility Testing

Device implementations MUST pass all tests described in this section.

However, note that no software test package is fully comprehensive. For this reason, device implementers are very strongly encouraged to make the minimum number of changes as possible to the reference and preferred implementation of Android 4.0 available from the Android Open Source Project. This will minimize the risk of introducing bugs that create incompatibilities requiring rework and potential device updates.

10.1. Compatibility Test Suite

Device implementations MUST pass the Android Compatibility Test Suite (CTS) [ Resources, 2 ] available from the Android Open Source Project, using the final shipping software on the device. Additionally, device implementers SHOULD use the reference implementation in the Android Open Source tree as much as possible, and MUST ensure compatibility in cases of ambiguity in CTS and for any reimplementations of parts of the reference source code.

The CTS is designed to be run on an actual device. Like any software, the CTS may itself contain bugs. The CTS will be versioned independently of this Compatibility Definition, and multiple revisions of the CTS may be released for Android 4.0. Device implementations MUST pass the latest CTS version available at the time the device software is completed.

10.2. CTS Verifier

Device implementations MUST correctly execute all applicable cases in the CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite, and is intended to be run by a human operator to test functionality that cannot be tested by an automated system, such as correct functioning of a camera and sensors.

The CTS Verifier has tests for many kinds of hardware, including some hardware that is optional. Device implementations MUST pass all tests for hardware which they possess; for instance, if a device possesses an accelerometer, it MUST correctly execute the Accelerometer test case in the CTS Verifier. Test cases for features noted as optional by this Compatibility Definition Document MAY be skipped or omitted.

Every device and every build MUST correctly run the CTS Verifier, as noted above. However, since many builds are very similar, device implementers are not expected to explicitly run the CTS Verifier on builds that differ only in trivial ways. Specifically, device implementations that differ from an implementation that has passed the CTS Verfier only by the set of included locales, branding, etc. MAY omit the CTS Verifier test.

10.3. Reference Applications

Device implementers MUST test implementation compatibility using the following open source applications:

  • The "Apps for Android" applications [ Resources, 55 ].
  • Replica Island (available in Android Market)

Each app above MUST launch and behave correctly on the implementation, for the implementation to be considered compatible.

11. Updatable Software

Device implementations MUST include a mechanism to replace the entirety of the system software. The mechanism need not perform "live" upgrades - that is, a device restart MAY be required.

Any method can be used, provided that it can replace the entirety of the software preinstalled on the device. For instance, any of the following approaches will satisfy this requirement:

  • Over-the-air (OTA) downloads with offline update via reboot
  • "Tethered" updates over USB from a host PC
  • "Offline" updates via a reboot and update from a file on removable storage

The update mechanism used MUST support updates without wiping user data. That is, the update mechanism MUST preserve application private data and application shared data. Note that the upstream Android software includes an update mechanism that satisfies this requirement.

If an error is found in a device implementation after it has been released but within its reasonable product lifetime that is determined in consultation with the Android Compatibility Team to affect the compatibility of third-party applications, the device implementer MUST correct the error via a software update available that can be applied per the mechanism just described.

12. Contact Us

You can contact the document authors at compatibility@android.com for clarifications and to bring up any issues that you think the document does not cover.

Appendix A - Bluetooth Test Procedure

The Compatibility Test Suite includes cases that cover basic operation of the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications protocol between devices, it cannot be fully tested by unit tests running on a single device. Consequently, device implementations MUST also pass the human-operated Bluetooth test procedure described below.

The test procedure is based on the BluetoothChat sample app included in the Android open source project tree. The procedure requires two devices:

  • a candidate device implementation running the software build to be tested
  • a separate device implementation already known to be compatible, and of a model from the device implementation being tested - that is, a "known good" device implementation

The test procedure below refers to these devices as the "candidate" and "known good" devices, respectively.

Setup and Installation

  1. Build BluetoothChat.apk via 'make samples' from an Android source code tree.
  2. Install BluetoothChat.apk on the known-good device.
  3. Install BluetoothChat.apk on the candidate device.

Test Bluetooth Control by Apps

  1. Launch BluetoothChat on the candidate device, while Bluetooth is disabled.
  2. Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth.

Test Pairing and Communication

  1. Launch the Bluetooth Chat app on both devices.
  2. Make the known-good device discoverable from within BluetoothChat (using the Menu).
  3. On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device.
  4. Send 10 or more messages from each device, and verify that the other device receives them correctly.
  5. Close the BluetoothChat app on both devices by pressing Home .
  6. Unpair each device from the other, using the device Settings app.

Test Pairing and Communication in the Reverse Direction

  1. Launch the Bluetooth Chat app on both devices.
  2. Make the candidate device discoverable from within BluetoothChat (using the Menu).
  3. On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.
  4. Send 10 or messages from each device, and verify that the other device receives them correctly.
  5. Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.

Test Re-Launches

  1. Re-launch the Bluetooth Chat app on both devices.
  2. Send 10 or messages from each device, and verify that the other device receives them correctly.

Note: the above tests have some cases which end a test section by using Home, and some using Back. These tests are not redundant and are not optional: the objective is to verify that the Bluetooth API and stack works correctly both when Activities are explicitly terminated (via the user pressing Back, which calls finish()), and implicitly sent to background (via the user pressing Home.) Each test sequence MUST be performed as described.