Android|Android 显示刷新频率的实现代码 Android显示刷新频率的实现代码

【Android|Android 显示刷新频率的实现代码】Android 显示刷新频率
android11-release

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开发者选项->显示刷新频率
packages/apps/Settings/src/com/android/settings/development/ShowRefreshRatePreferenceController.java

调用 SurfaceFlinger::onTransact 中 1034 方法
updateShowRefreshRateSetting() 通过 SurfaceFlinger 获取 mRefreshRateOverlay != nullptr 判断显示是否打开
writeShowRefreshRateSetting(boolean isEnabled) 设置打开显示刷新频率

public class ShowRefreshRatePreferenceController extends DeveloperOptionsPreferenceControllerimplements Preference.OnPreferenceChangeListener, PreferenceControllerMixin {private static final String SHOW_REFRESH_RATE_KEY = "show_refresh_rate"; private static final int SETTING_VALUE_QUERY = 2; private static final int SETTING_VALUE_ON = 1; private static final int SETTING_VALUE_OFF = 0; @VisibleForTestingstatic final String SURFACE_FLINGER_SERVICE_KEY = "SurfaceFlinger"; @VisibleForTestingstatic final int SURFACE_FLINGER_CODE = 1034; private static final String SURFACE_COMPOSER_INTERFACE_KEY = "android.ui.ISurfaceComposer"; private final IBinder mSurfaceFlinger; public ShowRefreshRatePreferenceController(Context context) {super(context); mSurfaceFlinger = ServiceManager.getService(SURFACE_FLINGER_SERVICE_KEY); }@Overridepublic String getPreferenceKey() {return SHOW_REFRESH_RATE_KEY; }@Overridepublic boolean onPreferenceChange(Preference preference, Object newValue) {final boolean isEnabled = (Boolean) newValue; writeShowRefreshRateSetting(isEnabled); return true; }@Overridepublic void updateState(Preference preference) {updateShowRefreshRateSetting(); }@Overrideprotected void onDeveloperOptionsSwitchDisabled() {super.onDeveloperOptionsSwitchDisabled(); final SwitchPreference preference = (SwitchPreference) mPreference; if (preference.isChecked()) {// Writing false to the preference when the setting is already off will have a// side effect of turning on the preference that we wish to avoidwriteShowRefreshRateSetting(false); preference.setChecked(false); }}@VisibleForTestingvoid updateShowRefreshRateSetting() {// magic communication with surface flinger.try {if (mSurfaceFlinger != null) {final Parcel data = https://www.it610.com/article/Parcel.obtain(); final Parcel reply = Parcel.obtain(); data.writeInterfaceToken(SURFACE_COMPOSER_INTERFACE_KEY); data.writeInt(SETTING_VALUE_QUERY); mSurfaceFlinger.transact(SURFACE_FLINGER_CODE, data, reply, 0 /* flags */); final boolean enabled = reply.readBoolean(); ((SwitchPreference) mPreference).setChecked(enabled); reply.recycle(); data.recycle(); }} catch (RemoteException ex) {// intentional no-op}}@VisibleForTestingvoid writeShowRefreshRateSetting(boolean isEnabled) {try {if (mSurfaceFlinger != null) {final Parcel data = Parcel.obtain(); data.writeInterfaceToken(SURFACE_COMPOSER_INTERFACE_KEY); final int showRefreshRate = isEnabled ? SETTING_VALUE_ON : SETTING_VALUE_OFF; data.writeInt(showRefreshRate); mSurfaceFlinger.transact(SURFACE_FLINGER_CODE, data,null /* reply */, 0 /* flags */); data.recycle(); }} catch (RemoteException ex) {// intentional no-op}updateShowRefreshRateSetting(); }}

RefreshRateOverlay 实际Layer显示刷新频率