窗口管理器

窗口管理器相关的几个线程：
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WindowManagerService 类的mian函数调用：
WMThread thr = new WMThread(context, pm, haveInputMethods)
创建窗口线程  WMThread 在线程 run中 实例化 WindowManagerService 类
WindowManagerService s = new WindowManagerService(mContext, mPM,mHaveInputMethods)
然后进入 Looper.loop();
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WindowManagerService构造函数里面有
  mQueue = new KeyQ();
因为  KeyQ 继承 KeyInputQueue 而 KeyInputQueue 中有
Thread mThread = new Thread("InputDeviceReader")
在线程 InputDeviceReader 里面通过  readEvent(ev) 读取事件
readEvent本地调用 com_android_server_KeyInputQueue.cpp (frameworks\base\services\jni)中的函数
static jboolean android_server_KeyInputQueue_readEvent(JNIEnv* env, jobject clazz,jobject event)
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WindowManagerService构造函数里面有
PolicyThread thr = new PolicyThread(mPolicy, this, context, pm);
创建 PolicyThread 线程
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WindowManagerService构造函数里面有
mInputThread = new InputDispatcherThread();
mInputThread.start();
首先执行 run 函数，在里面循环调用 process()
在 process()里面对事件进行分发：
按键事件：   dispatchKey((KeyEvent)ev.event, 0, 0);
触摸屏事件：dispatchPointer(ev, (MotionEvent)ev.event, 0, 0);
轨迹球事件：dispatchTrackball(ev, (MotionEvent)ev.event, 0, 0);
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private boolean dispatchKey(KeyEvent event, int pid, int uid)
  Object focusObj = mKeyWaiter.waitForNextEventTarget(event, null,null, false, false)
    Object waitForNextEventTarget(KeyEvent nextKey, QueuedEvent qev,MotionEvent nextMotion, boolean isPointerEvent,boolean failIfTimeout)
      Object findTargetWindow(KeyEvent nextKey, QueuedEvent qev,MotionEvent nextMotion, boolean isPointerEvent)