Data layar utama Android disediakan oleh class LauncherProvider, yang memperluas ContentProvider, sehingga memungkinkan impor dan ekspor data ruang kerja Peluncur menggunakan XML.
Berinteraksi dengan penyedia konten
Untuk berinteraksi dengan class LaunchProvider, yang memperluas ContentProvider,
gunakan metode call:
class LauncherProvider : ContentProvider {
    public Bundle call(String method, String arg, Bundle extras);
}
Memanggil class LaunchProvider
Untuk memanggil class LauncherProvider dari aplikasi Anda, gunakan kode berikut:
class YourClass {
    /**
     * This method imports Launcher workspace data as a XML string. Calling this method clears the old
     * data model within Launcher and replaces it with the imported data. It should be noted
     * that it doesn't need to clear all the Launcher's data, just what is similar to what is being imported.
     */
    fun importLauncherData(xmlRepresentation: String, ctx: Context): Boolean {
        val uri = try {
            getLauncherProviderUri(ctx)
        } catch (e: IllegalStateException) {
            Log.e(TAG, "Failed to get launcher provider URI", e)
            return false
        }
        val bundle = ctx.contentResolver.call(
            uri,
            LauncherProviderConstants.METHOD_IMPORT_LAYOUT_XML,
            xmlRepresentation,
            null,
        )
        return LauncherProviderConstants.SUCCESS
            .equals(bundle.getBoolean(LauncherProviderConstants.KEY_RESULT))
    }
    /**
     * Use this function to retrieve an XML string representation of the Launcher's Workspace.
     * This method doesn't return what the user sees on their home screen,
     * but rather what is in their data model at the moment it's called.
     */
    fun exportLauncherData(xmlRepresentation: String, ctx: Context): String {
        val uri = try {
            getLauncherProviderUri(ctx)
        } catch (e: IllegalStateException) {
            Log.e(TAG, "Failed to get launcher provider URI", e)
            return ""
        }
        val bundle = ctx.contentResolver.call(
            uri,
            LauncherProviderConstants.METHOD_EXPORT_LAYOUT_XML,
            null,
            null,
        )
        if (LauncherProviderConstants.FAILURE
            .equals(bundle.getBoolean(LauncherProviderConstants.KEY_RESULT))) {
            Log.e(TAG, "failed to export launcher data; review previous logs for the cause.")
        }
        return bundle.getString(LauncherProviderConstants.KEY_LAYOUT, "")
    }
    /**
     * Returns a Uri for interacting with Launcher's ContentProvider.
     *
     * Not all Launchers implement this api. This method throws an IllegalStateException
     * if the Launcher doesn't support it.
     */
    private fun getLauncherProviderUri(ctx: Context): Uri {
        val homeIntent = Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_HOME)
        val launcherPackage: String =
            ctx.packageManager
                .resolveActivity(homeIntent, PackageManager.MATCH_DEFAULT_ONLY)
                ?.activityInfo
                ?.packageName ?: throw IllegalStateException("No launcher package found")
        val authority = "${launcherPackage}.settings"
        ctx.packageManager.resolveContentProvider(authority, 0)
            ?: throw IllegalStateException(
                "Launcher package '$launcherPackage' does not support LauncherProvider",
            )
        return "content://$authority".toUri()
    }
}
Parameter
Konstanta ini digunakan dalam metode panggilan:
object LauncherProviderConstants {
    // Valid arg parameters for export and import operations
    private static final String METHOD_EXPORT_LAYOUT_XML = "EXPORT_LAYOUT_XML";
    private static final String METHOD_IMPORT_LAYOUT_XML = "IMPORT_LAYOUT_XML";
    // Bundle key and value set for determining if operation completed successfully or not
    private static final String KEY_RESULT = "KEY_RESULT";
    private static final String SUCCESS = "success";
    private static final String FAILURE = "failure";
    // Bundle key used to store exported XML-string representation of Launcher's workspace layout
    // and item metadata
    private static final String KEY_LAYOUT = "KEY_LAYOUT";
}
Gunakan konstanta LauncherProvider dengan batasan berikut:
- Gunakan metode contentResolver.calldenganEXPORT_LAYOUT_XMLsebagai parameter metode untuk mengekspor representasi XML ruang kerja peluncur.
- Selama ekspor, representasi XML dapat diakses dalam paket yang ditampilkan menggunakan kunci KEY_LAYOUT.
- Gunakan metode contentResolver.calldenganIMPORT_LAYOUT_XMLsebagai parameter metode untuk mengimpor representasi XML ruang kerja peluncur.
- Selama impor, representasi XML diberikan sebagai parameter argmetode panggilan.
- Untuk panggilan API ekspor dan impor, penyelesaian operasi yang dipilih
akan menampilkan success, dan operasi yang terganggu atau gagal akan menampilkanfailure.
- Nilai successataufailuredapat diambil dalam paket yang ditampilkan menggunakan kunciKEY_RESULT.
Untuk contoh, lihat Memanggil class LaunchProvider.
Representasi XML
Gunakan panduan berikut untuk struktur XML selama impor dan ekspor.
- Aplikasi Workspace: - <?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <workspace rows="4" columns="5"> <autoinstall container="desktop" x="1" y="1" screen="0" className="com.android.launcher3.tests.Activity2" packageName="com.google.android.apps.nexuslauncher" /> </workspace>
- Aplikasi Hotseat: - <?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <workspace> <autoinstall container="hotseat" rank="0" className="com.android.launcher3.tests.Activity2" packageName="com.google.android.apps.nexuslauncher" /> </workspace>
- Widget: - <?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <workspace> <appwidget container="desktop" spanX="2" spanY="2" x="0" y="1" screen="0" className="PlaceholderWidget" packageName="com.test.pending" /> </workspace>
- Folder: - <?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <workspace> <folder container="desktop" x="1" y="1" screen="1" titleText="CustomFolder"> <autoinstall className="com.android.launcher3.tests.Activity1" packageName="com.google.android.apps.nexuslauncher" /> <autoinstall className="com.android.launcher3.tests.Activity2" packageName="com.google.android.apps.nexuslauncher" /> <autoinstall className="com.android.launcher3.tests.Activity3" packageName="com.google.android.apps.nexuslauncher" /> </folder> </workspace>
- Pintasan dalam: - <?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <workspace> <shortcut shortcutId="shortcut2" packageName="com.google.android.apps.nexuslauncher.tests" /> </workspace>
- Pasangan aplikasi: - <?xml version='1.0' encoding='UTF-8' standalone='yes' ?> <workspace> <apppair container="desktop" x="1" y="1" screen="1" titleText="CustomFolder"> <autoinstall className="com.android.launcher3.tests.Activity1" packageName="com.google.android.apps.nexuslauncher" /> <autoinstall className="com.android.launcher3.tests.Activity2" packageName="com.google.android.apps.nexuslauncher" /> </apppair> </workspace>
Asumsi perilaku
Berikut adalah asumsi perilaku untuk class LaunchProvider.
- Metode bersifat atomik dan memblokir.
- Data serupa di peluncur akan ditimpa selama impor, sehingga hanya data yang baru diimpor yang tersisa.
- Data yang diimpor dapat langsung diakses; mengekspor tepat setelah mengimpor akan menampilkan data baru.
