Android P WMS初始化过程
Android P WMS简介
Android P WMS初始化过程
Android P WMS addwindow流程
Android P WMS removewindow流程
Android P WMS relayoutWindow流程
Android P WMS windowanimator
Android P WMS Surface
Android P WMS 问题种类和debug分析技巧
Android P WMS View System 简介
Android P WMS初始化过程
- @/frameworks/base/services/java/com/android/server/SystemServer. java
- private void startOtherServices () {
- WindowManagerService wm = null;
- InputManagerService inputManager = null;
-
- traceBeginAndSlog( "InitWatchdog");
- final Watchdog watchdog = Watchdog.getInstance();
- watchdog.init(context, mActivityManagerService);
- traceEnd();
-
- traceBeginAndSlog( "StartInputManagerService");
- inputManager = new InputManagerService(context); //4 需要input，因此才有事件输入
- traceEnd();
-
- traceBeginAndSlog( "StartWindowManagerService");
- // WMS needs sensor service ready
- ConcurrentUtils.waitForFutureNoInterrupt(mSensorServiceStart, START_SENSOR_SERVICE);
- mSensorServiceStart = null;
- wm = WindowManagerService.main(context, inputManager,
- mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
- !mFirstBoot, mOnlyCore, new PhoneWindowManager());
- ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
- DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);
- ServiceManager.addService(Context.INPUT_SERVICE, inputManager,
- /* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);
- traceEnd();
-
- traceBeginAndSlog( "SetWindowManagerService");
- mActivityManagerService.setWindowManager(wm);
- traceEnd();
-
- traceBeginAndSlog( "WindowManagerServiceOnInitReady");
- wm.onInitReady(); //android o没有
- traceEnd();
-
-
- traceBeginAndSlog( "StartInputManager");
- inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
- inputManager.start();
- traceEnd();
-
- // TODO: Use service dependencies instead.
- traceBeginAndSlog( "DisplayManagerWindowManagerAndInputReady");
- mDisplayManagerService.windowManagerAndInputReady();
- traceEnd();
-
-
- traceBeginAndSlog( "MakeWindowManagerServiceReady");
- try {
- wm.systemReady();
- } catch (Throwable e) {
- reportWtf( "making Window Manager Service ready", e);
- }
- traceEnd();
-
-
- // Update the configuration for this context by hand, because we're going
- // to start using it before the config change done in wm.systemReady() will
- // propagate to it.
- final Configuration config = wm.computeNewConfiguration(DEFAULT_DISPLAY);
- DisplayMetrics metrics = new DisplayMetrics();
- WindowManager w = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
- w.getDefaultDisplay().getMetrics(metrics);
- context.getResources().updateConfiguration(config, metrics);
-
- }
startOtherServices方法用于启动其他服务，其他服务大概有70多个，上面的代码只列出了WMS以及和它相关的IMS的启动逻辑，剩余的其他服务的启动逻辑也都大同小异。
在注释1、2处分别得到Watchdog实例并对它进行初始化，Watchdog用来监控系统的一些关键服务的运行状况，后文会再次提到它。在注释3处创建了IMS，并赋值给IMS类型的inputManager对象。注释4处执行了WMS的main方法，其内部会创建WMS，需要注意的是main方法其中一个传入的参数就是注释1处创建的IMS，WMS是输入事件的中转站，其内部包含了IMS引用并不意外。结合上文，我们可以得知WMS的main方法是运行在SystemServer的run方法中，换句话说就是运行在”system_server”线程”中，后面会再次提到”system_server”线程。
注释5和注释6处分别将WMS和IMS注册到ServiceManager中，这样如果某个客户端想要使用WMS，就需要先去ServiceManager中查询信息，然后根据信息与WMS所在的进程建立通信通路，客户端就可以使用WMS了。注释7处用来初始化显示信息，注释8处则用来通知WMS，系统的初始化工作已经完成，其内部调用了WindowManagerPolicy的systemReady方法。
- @http: //androidxref.com/9.0.0_r3/xref/frameworks/base/services/java/com/android/server/SystemServer.java#875
- private WindowManagerService(Context context, InputManagerService inputManager,
- boolean haveInputMethods, boolean showBootMsgs, boolean onlyCore,
- WindowManagerPolicy policy) {
-
- mInputManager = inputManager; // Must be before createDisplayContentLocked.
- mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class);
- mDisplaySettings = new DisplaySettings();
- mDisplaySettings.readSettingsLocked();
-
- mPolicy = policy;
- mAnimator = new WindowAnimator( this); //创建了WindowAnimator，它用于管理所有的窗口动画
- mRoot = new RootWindowContainer( this);
-
- mWindowPlacerLocked = new WindowSurfacePlacer( this);
- mTaskSnapshotController = new TaskSnapshotController( this);
-
- mWindowTracing = WindowTracing.createDefaultAndStartLooper(context);
-
- LocalServices.addService(WindowManagerPolicy.class, mPolicy);
-
- if(mInputManager != null) {
- final InputChannel inputChannel = mInputManager.monitorInput(TAG_WM);
- mPointerEventDispatcher = inputChannel != null
- ? new PointerEventDispatcher(inputChannel) : null;
- } else {
- mPointerEventDispatcher = null;
- }
-
- mDisplayManager = (DisplayManager)context.getSystemService(Context.DISPLAY_SERVICE);
-
- mKeyguardDisableHandler = new KeyguardDisableHandler(mContext, mPolicy);
-
- ...
-
- //得到AMS实例，并赋值给mActivityManager ，这样WMS就持有了AMS的引用
- mActivityManager = ActivityManager.getService();
- mAmInternal = LocalServices.getService(ActivityManagerInternal.class);
-
- IntentFilter filter = new IntentFilter();
- // Track changes to DevicePolicyManager state so we can enable/disable keyguard.
- filter.addAction(ACTION_DEVICE_POLICY_MANAGER_STATE_CHANGED);
- mContext.registerReceiver(mBroadcastReceiver, filter);
-
- mLatencyTracker = LatencyTracker.getInstance(context);
-
- mSettingsObserver = new SettingsObserver();
-
- mHoldingScreenWakeLock = mPowerManager.newWakeLock(
- PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE, TAG_WM);
- mHoldingScreenWakeLock.setReferenceCounted( false);
-
- mSurfaceAnimationRunner = new SurfaceAnimationRunner();
-
-
-
- LocalServices.addService(WindowManagerInternal.class, new LocalService());
- }
-
-
- public void onInitReady() {
- initPolicy(); //初始化了窗口管理策略的接口类WindowManagerPolicy（WMP）
-
- // Add ourself to the Watchdog monitors.
- Watchdog.getInstance().addMonitor( this); //加入到watchdog
-
- openSurfaceTransaction();
- try {
- createWatermarkInTransaction();
- } finally {
- closeSurfaceTransaction( "createWatermarkInTransaction");
- }
-
- showEmulatorDisplayOverlayIfNeeded();
- }
- private void initPolicy() {
- UiThread.getHandler().runWithScissors( new Runnable() {
- @Override
- public void run() {
- WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper());
- mPolicy.init(mContext, WindowManagerService. this, WindowManagerService. this);
- }
- }, 0);
- }
运行线程状态
initPolicy方法和此前讲的WMS的main方法的实现类似，注释1处执行了WMP的init方法，WMP是一个接口，init方法的具体实现在PhoneWindowManager（PWM）中。PWM的init方法运行在”android.ui”线程中，它的优先级要高于initPolicy方法所在的”android.display”线程，因此”android.display”线程要等PWM的init方法执行完毕后，处于等待状态的”android.display”线程才会被唤醒从而继续执行下面的代码。
在本文中共提到了3个线程，分别是”system_server”、”android.display”和”android.ui”，为了便于理解，下面给出这三个线程之间的关系。
main运行在DisplayThread(android.display),initPolicy运行在UiThread(android.ui)
- //android.display thread
- public static WindowManagerService main(final Context context, final InputManagerService im,
- final boolean haveInputMethods, final boolean showBootMsgs, final boolean onlyCore,
- WindowManagerPolicy policy) {
- DisplayThread.getHandler().runWithScissors(() ->
- sInstance = new WindowManagerService(context, im, haveInputMethods, showBootMsgs,
- onlyCore, policy), 0);
- return sInstance;
- }
-
-
- //android.ui thread
- private void initPolicy() {
- UiThread.getHandler().runWithScissors( new Runnable() {
- @Override
- public void run() {
- WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper());
- mPolicy.init(mContext, WindowManagerService. this, WindowManagerService. this);
- }
- }, 0);
- }
- //DisplayThread android.display
- /frameworks/base/services/core/java/com/android/server/
- H A DDisplayThread.java 36 super( "android.display", Process.THREAD_PRIORITY_DISPLAY + 1, false /*allowIo*/);
-
- //UiThread android.ui
- /frameworks/base/services/core/java/com/android/server/
- H A DUiThread.java 36 super( "android.ui", Process.THREAD_PRIORITY_FOREGROUND, false /*allowIo*/);
“system_server”线程中会调用WMS的main方法，main方法中会创建WMS，创建WMS的过程运行在”android.display”线程中，它的优先级更高一些，因此要等创建WMS完毕后才会唤醒处于等待状态的”system_server”线程。
WMS初始化时会执行initPolicy方法，initPolicy方法会调用PWM的init方法，这个init方法运行在”android.ui”线程，并且优先级更高，因此要先执行完PWM的init方法后，才会唤醒处于等待状态的”android.display”线程。
PWM的init方法执行完毕后会接着执行运行在”system_server”线程的代码，比如本文前部分提到WMS的
systemReady方法。
总结
wms初始化和前面的android版本变化不是很大，可以进行对比分析
源码路径： http://androidxref.com/9.0.0_r3/
参考书籍: Android解析WindowManager系列
Android解析WindowManagerService（一）WMS的诞生
《深入理解Android：卷III》
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