WindowManagerService启动篇

一. 概述

Surface:代表画布
WMS: 添加window的过程主要功能是添加Surface,管理所有的Surface布局,以及Z轴排序问题;
SurfaceFinger: 将Surface按次序混合并显示到物理屏幕上;

1.1 类图

说明:

WMS继承于 IWindowManager.Stub , 作为Binder服务端;
WMS的成员变量mSessions保存着所有的Session对象,Session继承于 IWindowSession.Stub , 作为Binder服务端;
成员变量mPolicy: 实例对象为PhoneWindowManager,用于实现各种窗口相关的策略;
成员变量mChoreographer: 用于控制窗口动画,屏幕旋转等操作;
成员变量mDisplayContents: 记录一组DisplayContent对象,这个跟多屏输出相关;
成员变量mTokenMap: 保存所有的WindowToken对象; 以IBinder为key,可以是IAppWindowToken或者其他Binder的Bp端;
- 另一端情况:ActivityRecord.Token extends IApplicationToken.Stub
成员变量mWindowMap: 保存所有的WindowState对象;以IBinder为key, 是IWindow的Bp端;
- 另一端情况: ViewRootImpl.W extends IWindow.Stub
一般地,每一个窗口都对应一个WindowState对象, 该对象的成员变量mClient用于跟应用端交互,成员变量mToken用于跟AMS交互.

二. 启动过程

private void startOtherServices() { ... // [见小节2.1] WindowManagerService wm = WindowManagerService.main(context, inputManager, mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL, !mFirstBoot, mOnlyCore); wm.displayReady(); // [见小节2.5] ... wm.systemReady(); // [见小节2.6] }

2.1 WMS.main

[-> WindowManagerService.java]

public static WindowManagerService main(final Context context, final InputManagerService im, final boolean haveInputMethods, final boolean showBootMsgs, final boolean onlyCore) { final WindowManagerService[] holder = new WindowManagerService[1]; DisplayThread.getHandler().runWithScissors(new Runnable() { public void run() { //运行在"android.display"线程[见小节2.2] holder[0] = new WindowManagerService(context, im, haveInputMethods, showBootMsgs, onlyCore); } }, 0); return holder[0]; }

2.2 WindowManagerService

private WindowManagerService(Context context, InputManagerService inputManager, boolean haveInputMethods, boolean showBootMsgs, boolean onlyCore) { mContext = context; mHaveInputMethods = haveInputMethods; mAllowBootMessages = showBootMsgs; mOnlyCore = onlyCore; ... mInputManager = inputManager; mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class); mDisplaySettings = new DisplaySettings(); mDisplaySettings.readSettingsLocked(); LocalServices.addService(WindowManagerPolicy.class, mPolicy); mPointerEventDispatcher = new PointerEventDispatcher(mInputManager.monitorInput(TAG)); mFxSession = new SurfaceSession(); mDisplayManager = (DisplayManager)context.getSystemService(Context.DISPLAY_SERVICE); mDisplays = mDisplayManager.getDisplays(); for (Display display : mDisplays) { //创建DisplayContent[见小节2.2.1] createDisplayContentLocked(display); } mKeyguardDisableHandler = new KeyguardDisableHandler(mContext, mPolicy); ... mAppTransition = new AppTransition(context, mH); mAppTransition.registerListenerLocked(mActivityManagerAppTransitionNotifier); mActivityManager = ActivityManagerNative.getDefault(); ... mAnimator = new WindowAnimator(this); LocalServices.addService(WindowManagerInternal.class, new LocalService()); //初始化策略[见小节2.3] initPolicy(); Watchdog.getInstance().addMonitor(this); SurfaceControl.openTransaction(); try { createWatermarkInTransaction(); mFocusedStackFrame = new FocusedStackFrame( getDefaultDisplayContentLocked().getDisplay(), mFxSession); } finally { SurfaceControl.closeTransaction(); } updateCircularDisplayMaskIfNeeded(); showEmulatorDisplayOverlayIfNeeded(); }

2.2.1 WMS.createDisplayContentLocked

public DisplayContent getDisplayContentLocked(final int displayId) { DisplayContent displayContent = mDisplayContents.get(displayId); if (displayContent == null) { final Display display = mDisplayManager.getDisplay(displayId); if (display != null) { displayContent = newDisplayContentLocked(display); } } return displayContent; }

创建DisplayContent,用于支持多屏幕的功能.比如目前除了本身真实的屏幕之外,还有Wifi display虚拟屏幕.

2.3 WMS.initPolicy

private void initPolicy() { //运行在"android.ui"线程 UiThread.getHandler().runWithScissors(new Runnable() { public void run() { WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper()); //此处mPolicy为PhoneWindowManager.[见小节2.4] mPolicy.init(mContext, WindowManagerService.this, WindowManagerService.this); } }, 0); }

2.3.1 Handler.runWithScissors

[-> Handler.java]

public final boolean runWithScissors(final Runnable r, long timeout) { //当前线程跟当前Handler都指向同一个Looper,则直接运行 if (Looper.myLooper() == mLooper) { r.run(); return true; } BlockingRunnable br = new BlockingRunnable(r); //[见小节2.3.2] return br.postAndWait(this, timeout); }

2.3.2 postAndWait

[-> Handler.java ::BlockingRunnable]

private static final class BlockingRunnable implements Runnable { private final Runnable mTask; private boolean mDone; public BlockingRunnable(Runnable task) { mTask = task; } public void run() { try { mTask.run(); } finally { synchronized (this) { mDone = true; notifyAll(); } } } public boolean postAndWait(Handler handler, long timeout) { if (!handler.post(this)) { return false; } synchronized (this) { if (timeout > 0) { final long expirationTime = SystemClock.uptimeMillis() + timeout; while (!mDone) { long delay = expirationTime - SystemClock.uptimeMillis(); if (delay <= 0) { return false; // timeout } try { wait(delay); } catch (InterruptedException ex) { } } } else { while (!mDone) { try { wait(); } catch (InterruptedException ex) { } } } } return true; } }

由此可见, BlockingRunnable.postAndWait()方法是阻塞操作,就是先将消息放入Handler所指向的线程, 此处是指”android.ui”线程, 由于该方法本身运行在system_server主线程. 也就意味着system_server线程会进入等待状态, 直到handler线程执行完成后再唤醒system_server主线程. 那么PWM.init()便是运行在”android.ui”线程,属于同步阻塞操作.

2.4 PWM.init

[-> PhoneWindowManager.java]

public void init(Context context, IWindowManager windowManager, WindowManagerFuncs windowManagerFuncs) { mContext = context; mWindowManager = windowManager; mWindowManagerFuncs = windowManagerFuncs; mWindowManagerInternal = LocalServices.getService(WindowManagerInternal.class); mActivityManagerInternal = LocalServices.getService(ActivityManagerInternal.class); mDreamManagerInternal = LocalServices.getService(DreamManagerInternal.class); mPowerManagerInternal = LocalServices.getService(PowerManagerInternal.class); mAppOpsManager = (AppOpsManager) mContext.getSystemService(Context.APP_OPS_SERVICE); ... mHandler = new PolicyHandler(); //运行在"android.ui"线程 mWakeGestureListener = new MyWakeGestureListener(mContext, mHandler); mOrientationListener = new MyOrientationListener(mContext, mHandler); ... mPowerManager = (PowerManager)context.getSystemService(Context.POWER_SERVICE); mBroadcastWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "PhoneWindowManager.mBroadcastWakeLock"); mPowerKeyWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "PhoneWindowManager.mPowerKeyWakeLock"); ... mGlobalKeyManager = new GlobalKeyManager(mContext); ... if (!mPowerManager.isInteractive()) { startedGoingToSleep(WindowManagerPolicy.OFF_BECAUSE_OF_USER); finishedGoingToSleep(WindowManagerPolicy.OFF_BECAUSE_OF_USER); } mWindowManagerInternal.registerAppTransitionListener( mStatusBarController.getAppTransitionListener()); }

前面小节[2.1 ~ 2.4]介绍了WMS.main()方法, 接下来便是开始执行WMS.displayReady().

2.5 WMS.displayReady

public void displayReady() { for (Display display : mDisplays) { displayReady(display.getDisplayId()); } synchronized(mWindowMap) { final DisplayContent displayContent = getDefaultDisplayContentLocked(); readForcedDisplayPropertiesLocked(displayContent); mDisplayReady = true; } mActivityManager.updateConfiguration(null); synchronized(mWindowMap) { mIsTouchDevice = mContext.getPackageManager().hasSystemFeature( PackageManager.FEATURE_TOUCHSCREEN); configureDisplayPolicyLocked(getDefaultDisplayContentLocked()); } mActivityManager.updateConfiguration(null); }

2.6 WMS.systemReady

public void systemReady() { mPolicy.systemReady(); }

2.6.1 PWM.systemReady

[-> PhoneWindowManager.java]

public void systemReady() { mKeyguardDelegate = new KeyguardServiceDelegate(mContext); mKeyguardDelegate.onSystemReady(); readCameraLensCoverState(); updateUiMode(); boolean bindKeyguardNow; synchronized (mLock) { updateOrientationListenerLp(); mSystemReady = true; mHandler.post(new Runnable() { public void run() { updateSettings(); } }); bindKeyguardNow = mDeferBindKeyguard; if (bindKeyguardNow) { mDeferBindKeyguard = false; } } if (bindKeyguardNow) { mKeyguardDelegate.bindService(mContext); mKeyguardDelegate.onBootCompleted(); } mSystemGestures.systemReady(); }