Android P系统设置之SettingsProvider源码分析

本文主要是介绍Android P系统设置之SettingsProvider源码分析，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

相关源码：
\frameworks\base\services\java\com\android\server\SystemServer.java
\frameworks\base\services\core\java\com\android\server\am\ActivityManagerService.java
\frameworks\base\packages\SettingsProvider\src\com\android\providers\settings\SettingsProvider.java

\frameworks\base\packages\SettingsProvider\res\values\defaults.xml

SettingsProvider是系统设置的内容提供者。

它将设置类型分类三类：

• Global，全局，对系统中所有用户公开，第三方App没有写权限
• Secure，安全相关的用户偏好设置，第三方App没有写权限
• System，用户偏好系统设置

在最新android 9.0系统中，数据存储由原来的数据库settings.db，转移保存到xml中：

• data/system/users/0/settings_global.xml
• data/system/users/userid/settings_system.xml
• data/system/users/userid/settings_secure.xml

settings.db删除不再使用。

SettingsProvider启动

\frameworks\base\services\java\com\android\server\SystemServer.java
在installSystemProviders()中启动了SettingsProvider

private void startOtherServices() {//省略一部分代码//...traceBeginAndSlog("InstallSystemProviders");mActivityManagerService.installSystemProviders();// Now that SettingsProvider is ready, reactivate SQLiteCompatibilityWalFlagsSQLiteCompatibilityWalFlags.reset();traceEnd();//省略一部分代码//...
}

\frameworks\base\services\core\java\com\android\server\am\ActivityManagerService.java
installSystemProviders()中三个关键的步骤，1,2,3

public final void installSystemProviders() {// 1、获取系统中所有的Provider，最终通过调用包管理PackageManagerService中的queryContentProviders()方法来查询所有的ProviderList<ProviderInfo> providers;synchronized (this) {ProcessRecord app = mProcessNames.get("system", SYSTEM_UID);providers = generateApplicationProvidersLocked(app);if (providers != null) {for (int i=providers.size()-1; i>=0; i--) {ProviderInfo pi = (ProviderInfo)providers.get(i);if ((pi.applicationInfo.flags&ApplicationInfo.FLAG_SYSTEM) == 0) {Slog.w(TAG, "Not installing system proc provider " + pi.name+ ": not system .apk");providers.remove(i);}}}}// 2、调用ActivityThread中的installSystemProviders来完成Provider的安装，包括SettingsProviderif (providers != null) {mSystemThread.installSystemProviders(providers);}synchronized (this) {mSystemProvidersInstalled = true;}mConstants.start(mContext.getContentResolver());mCoreSettingsObserver = new CoreSettingsObserver(this);mFontScaleSettingObserver = new FontScaleSettingObserver();mDevelopmentSettingsObserver = new DevelopmentSettingsObserver();GlobalSettingsToPropertiesMapper.start(mContext.getContentResolver());// 3、Provider启动完成// Now that the settings provider is published we can consider sending// in a rescue party.RescueParty.onSettingsProviderPublished(mContext);//mUsageStatsService.monitorPackages();
}

其中，第二步中，installSystemProviders()会调用到SettingsProvider中的onCreate()方法。

\frameworks\base\packages\SettingsProvider\src\com\android\providers\settings\SettingsProvider.java

@Override
public boolean onCreate() {Settings.setInSystemServer();// fail to boot if there're any backed up settings that don't have a non-null validatorensureAllBackedUpSystemSettingsHaveValidators();ensureAllBackedUpGlobalSettingsHaveValidators();ensureAllBackedUpSecureSettingsHaveValidators();synchronized (mLock) {mUserManager = UserManager.get(getContext());mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);mPackageManager = AppGlobals.getPackageManager();mHandlerThread = new HandlerThread(LOG_TAG,Process.THREAD_PRIORITY_BACKGROUND);mHandlerThread.start();mHandler = new Handler(mHandlerThread.getLooper());mSettingsRegistry = new SettingsRegistry();}mHandler.post(() -> {registerBroadcastReceivers();startWatchingUserRestrictionChanges();});ServiceManager.addService("settings", new SettingsService(this));return true;
}

其中，关键的部分是：mSettingsRegistry = new SettingsRegistry();

final class SettingsRegistry {private static final String DROPBOX_TAG_USERLOG = "restricted_profile_ssaid";private static final String SETTINGS_FILE_GLOBAL = "settings_global.xml";private static final String SETTINGS_FILE_SYSTEM = "settings_system.xml";private static final String SETTINGS_FILE_SECURE = "settings_secure.xml";private static final String SETTINGS_FILE_SSAID = "settings_ssaid.xml";private static final String SSAID_USER_KEY = "userkey";public SettingsRegistry() {mHandler = new MyHandler(getContext().getMainLooper());// 1、对xml的修改做版本管理mGenerationRegistry = new GenerationRegistry(mLock);// 2、创建Backup，做系统备份mBackupManager = new BackupManager(getContext());// 3、迁移所有的系统设置数据migrateAllLegacySettingsIfNeeded();syncSsaidTableOnStart();}private void migrateAllLegacySettingsIfNeeded() {synchronized (mLock) {final int key = makeKey(SETTINGS_TYPE_GLOBAL, UserHandle.USER_SYSTEM);.// 1、判断settings_global.xml是否存在，如果不存怎，就返回，不用做数据迁移//    所以，settings_global.xml一般都是存在，只有升级后系统第一次启动的时候才会不存在，//	  数据迁移，只会发生在系统升级后第一次启动的情况File globalFile = getSettingsFile(key);if (SettingsState.stateFileExists(globalFile)) {return;}mSettingsCreationBuildId = Build.ID;final long identity = Binder.clearCallingIdentity();try {// 2、获取系统中所有的用户(多用户，一般user0)List<UserInfo> users = mUserManager.getUsers(true);final int userCount = users.size();for (int i = 0; i < userCount; i++) {final int userId = users.get(i).id;// 3、关键代码，通过DatabaseHelper类创建数据库settings.db，并使用默认设置对数据库表数据初始化DatabaseHelper dbHelper = new DatabaseHelper(getContext(), userId);SQLiteDatabase database = dbHelper.getWritableDatabase();migrateLegacySettingsForUserLocked(dbHelper, database, userId);// 4、关键代码，生成和初始化xml文件// Upgrade to the latest version.UpgradeController upgrader = new UpgradeController(userId);upgrader.upgradeIfNeededLocked();// Drop from memory if not a running user.if (!mUserManager.isUserRunning(new UserHandle(userId))) {removeUserStateLocked(userId, false);}}} finally {Binder.restoreCallingIdentity(identity);}}}
}

重点，migrateLegacySettingsForUserLocked()和upgradeIfNeededLocked()。

DatabaseHelper类

SettingsRegistry类中的migrateAllLegacySettingsIfNeeded中执行了DatabaseHelper去创建数据库settings.db.
DatabaseHelper dbHelper = new DatabaseHelper(getContext(), userId);
SQLiteDatabase database = dbHelper.getWritableDatabase();
DatabaseHelper()中执行了dbNameForUser()，SQLiteOpenHelper 创建了数据库settings.db。
在settings.db数据库创建后，回调onCreate函数。onCreate()中,创建了数据的表。

class DatabaseHelper extends SQLiteOpenHelper {private static final String DATABASE_NAME = "settings.db";public DatabaseHelper(Context context, int userHandle) {super(context, dbNameForUser(userHandle), null, DATABASE_VERSION);mContext = context;mUserHandle = userHandle;}static String dbNameForUser(final int userHandle) {// The owner gets the unadorned db name;if (userHandle == UserHandle.USER_SYSTEM) {return DATABASE_NAME;} else {// Place the database in the user-specific data tree so that it's// cleaned up automatically when the user is deleted.File databaseFile = new File(Environment.getUserSystemDirectory(userHandle), DATABASE_NAME);// If databaseFile doesn't exist, database can be kept in memory. It's safe because the// database will be migrated and disposed of immediately after onCreate finishesif (!databaseFile.exists()) {Log.i(TAG, "No previous database file exists - running in in-memory mode");return null;}return databaseFile.getPath();}}@Overridepublic void onCreate(SQLiteDatabase db) {db.execSQL("CREATE TABLE system (" +"_id INTEGER PRIMARY KEY AUTOINCREMENT," +"name TEXT UNIQUE ON CONFLICT REPLACE," +"value TEXT" +");");db.execSQL("CREATE INDEX systemIndex1 ON system (name);");// 1、创建表，createSecureTable，Secure数据表createSecureTable(db);// 2、创建表，createGlobalTable，Global数据表// Only create the global table for the singleton 'owner/system' userif (mUserHandle == UserHandle.USER_SYSTEM) {createGlobalTable(db);}db.execSQL("CREATE TABLE bluetooth_devices (" +"_id INTEGER PRIMARY KEY," +"name TEXT," +"addr TEXT," +"channel INTEGER," +"type INTEGER" +");");db.execSQL("CREATE TABLE bookmarks (" +"_id INTEGER PRIMARY KEY," +"title TEXT," +"folder TEXT," +"intent TEXT," +"shortcut INTEGER," +"ordering INTEGER" +");");db.execSQL("CREATE INDEX bookmarksIndex1 ON bookmarks (folder);");db.execSQL("CREATE INDEX bookmarksIndex2 ON bookmarks (shortcut);");// Populate bookmarks table with initial bookmarksboolean onlyCore = false;try {onlyCore = IPackageManager.Stub.asInterface(ServiceManager.getService("package")).isOnlyCoreApps();} catch (RemoteException e) {}if (!onlyCore) {loadBookmarks(db);}// 3、默认数据填充数据库// Load initial volume levels into DBloadVolumeLevels(db);// 4、默认数据填充数据库// Load inital settings valuesloadSettings(db);}
}

Settings.db数据迁移到xml中

还是继续看SettingsRegistry 中的migrateLegacySettingsForUserLocked()和upgradeIfNeededLocked()，

SettingsProvider中几个数据类型的定义：

//SettingsState.java中
public static final int SETTINGS_TYPE_GLOBAL = 0;
public static final int SETTINGS_TYPE_SYSTEM = 1;
public static final int SETTINGS_TYPE_SECURE = 2;
public static final int SETTINGS_TYPE_SSAID = 3;
public static final int SETTINGS_TYPE_MASK = 0xF0000000;
public static final int SETTINGS_TYPE_SHIFT = 28;
//SettingsProvider.java中
public static final int SETTINGS_TYPE_GLOBAL = SettingsState.SETTINGS_TYPE_GLOBAL;
public static final int SETTINGS_TYPE_SYSTEM = SettingsState.SETTINGS_TYPE_SYSTEM;
public static final int SETTINGS_TYPE_SECURE = SettingsState.SETTINGS_TYPE_SECURE;
public static final int SETTINGS_TYPE_SSAID = SettingsState.SETTINGS_TYPE_SSAID;

final class SettingsRegistry {private void migrateLegacySettingsForUserLocked(DatabaseHelper dbHelper, SQLiteDatabase database, int userId) {// 1、处理System数据，	// Move over the system settings.final int systemKey = makeKey(SETTINGS_TYPE_SYSTEM, userId);//生成对应的SettingsState对象保存在mSettingsStates中，生成settings_system.xmlensureSettingsStateLocked(systemKey);SettingsState systemSettings = mSettingsStates.get(systemKey);//数据迁移，将settings.db的数据迁移到settings_system.xml中migrateLegacySettingsLocked(systemSettings, database, TABLE_SYSTEM);systemSettings.persistSyncLocked();// 2、处理Secure 数据，// Move over the secure settings.// Do this after System settings, since this is the first thing we check when deciding// to skip over migration from db to xml for a secondary user.final int secureKey = makeKey(SETTINGS_TYPE_SECURE, userId);//生成对应的SettingsState对象保存在mSettingsStates中，生成settings_secure.xmlensureSettingsStateLocked(secureKey);SettingsState secureSettings = mSettingsStates.get(secureKey);//数据迁移，将settings.db的数据迁移到settings_secure.xml中migrateLegacySettingsLocked(secureSettings, database, TABLE_SECURE);ensureSecureSettingAndroidIdSetLocked(secureSettings);secureSettings.persistSyncLocked();// 3、处理Global 数据，     // Move over the global settings if owner.// Do this last, since this is the first thing we check when deciding// to skip over migration from db to xml for owner user.if (userId == UserHandle.USER_SYSTEM) {final int globalKey = makeKey(SETTINGS_TYPE_GLOBAL, userId);//生成对应的SettingsState对象保存在mSettingsStates中，生成settings_global.xmlensureSettingsStateLocked(globalKey);SettingsState globalSettings = mSettingsStates.get(globalKey);//数据迁移，将settings.db的数据迁移到settings_global.xml中migrateLegacySettingsLocked(globalSettings, database, TABLE_GLOBAL);// If this was just createdif (mSettingsCreationBuildId != null) {globalSettings.insertSettingLocked(Settings.Global.DATABASE_CREATION_BUILDID,mSettingsCreationBuildId, null, true,SettingsState.SYSTEM_PACKAGE_NAME);}globalSettings.persistSyncLocked();}//数据迁移完成后，是否删除settings.db，或者做一个备份// Drop the database as now all is moved and persisted.if (DROP_DATABASE_ON_MIGRATION) {dbHelper.dropDatabase();} else {dbHelper.backupDatabase();}}//ensureSettingsStateLocked是一个重要的方法，给每一个数据类型key，穿件一个对应的SettingsState对象并保存在mSettingsStatesprivate void ensureSettingsStateLocked(int key) {if (mSettingsStates.get(key) == null) {final int maxBytesPerPackage = getMaxBytesPerPackageForType(getTypeFromKey(key));SettingsState settingsState = new SettingsState(getContext(), mLock,getSettingsFile(key), key, maxBytesPerPackage, mHandlerThread.getLooper());mSettingsStates.put(key, settingsState);}}}

SettingsState中，persistSyncLocked()方法最终完成xml的数据写入。

DatabaseHelper中settings.db的数据默认值来自于\frameworks\base\packages\SettingsProvider\res\values\defaults.xml。

具体是在loadSecureSettings()，loadSetting()方法中加载的。

Provider数据读写

写数据调用接口的方法：

// Add a persistent setting to allow other apps to know the device has been provisioned.
Settings.Secure.putInt(getContentResolver(), Settings.Secure.DEVICE_PROVISIONED, 1);// Enable the GPS.
// Not needed since this SDK will contain the Settings app.
Settings.Secure.putString(getContentResolver(),Settings.Secure.LOCATION_PROVIDERS_ALLOWED, LocationManager.GPS_PROVIDER);

读数据调用接口的方法：

Settings.Secure.getint(mContext.getContentResolver(),Settings.Secure.DEVICE_PROVISIONED);
Settings.Secure.getString(mContext.getContentResolver(),Settings.Secure.LOCATION_PROVIDERS_ALLOWED);

调式

1、在以下目录可以看到以下保存在xml中的值。

• data/system/users/0/settings_global.xml
• data/system/users/userid/settings_system.xml
• data/system/users/userid/settings_secure.xml

2、将private static final boolean DROP_DATABASE_ON_MIGRATION = false;设置为false,可以保存settings.db数据。
为true时会删除掉。

3、在DatabaseHelper类中loadSetting()方法打印数据：

private void loadSetting(SQLiteStatement stmt, String key, Object value) {Log.i(TAG, "sunxiaolin,loadSetting,key=" + key + ", value=" + value.toString());stmt.bindString(1, key);stmt.bindString(2, value.toString());stmt.execute();
}

2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=screen_brightness, value=102
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=screen_brightness_for_vr, value=86
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=screen_brightness_mode, value=0
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=accelerometer_rotation, value=0
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=haptic_feedback_enabled, value=1
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=notification_light_pulse, value=1
2019-09-12 15:08:29.271 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=dtmf_tone, value=1
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=sound_effects_enabled, value=1
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=haptic_feedback_enabled, value=1
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=lockscreen_sounds_enabled, value=1
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=pointer_speed, value=0
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=location_providers_allowed, value=gps,network
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=mock_location, value=1
2019-09-12 15:08:29.272 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=backup_enabled, value=0
2019-09-12 15:08:29.273 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=backup_transport, value=android/com.android.internal.backup.LocalTransport
2019-09-12 15:08:29.273 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=mount_play_not_snd, value=1
2019-09-12 15:08:29.273 1990-1990/? I/SettingsProvider: sunxiaolin,loadSetting,key=mount_ums_autostart, value=0

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