Android事件处理：按键、触摸屏和滚动球的一些实现细节

核心提示：}}readEvent() 实际上调用的是 com_android_server_KeyInputQueue.cpp (frameworksaseservicesjni)中的：static jboolean android_server_KeyInputQueue_readEvent(JNIEnv* env, job

}

}

readEvent() 实际上调用的是 com_android_server_KeyInputQueue.cpp (frameworksaseservicesjni)中的：

static jboolean android_server_KeyInputQueue_readEvent(JNIEnv* env, jobject clazz,jobject event)

bool res = hub->getEvent(&deviceId, &type, &scancode, &keycode,&flags, &value, &when);

调用的是 EventHub.cpp (frameworksaselibsui)中的：

bool EventHub::getEvent(int32_t* outDeviceId, int32_t* outType,

int32_t* outScancode, int32_t* outKeycode, uint32_t *outFlags,

int32_t* outValue, nsecs_t* outWhen)

在函数中调用了读设备操作：res = read(mFDs[i].fd, &iev, sizeof(iev));

在构造函数 WindowManagerService()调用 new KeyQ() 以后接着调用了：

mInputThread = new InputDispatcherThread();

...

mInputThread.start();

来启动一个线程 InputDispatcherThread

run()

process();

QueuedEvent ev = mQueue.getEvent(...)

因为WindowManagerService类中： final KeyQ mQueue;

所以实际上 InputDispatcherThread 线程实际上从 KeyQ 的事件队列中读取按键事件。

switch (ev.classType)

case RawInputEvent.CLASS_KEYBOARD:

...

dispatchKey((KeyEvent)ev.event, 0, 0);

mQueue.recycleEvent(ev);

break;

case RawInputEvent.CLASS_TOUCHSCREEN:

//Log.i(TAG, "Read next event " + ev);

dispatchPointer(ev, (MotionEvent)ev.event, 0, 0);

break;

KeyInputQueue.java (frameworksaseservicesjavacomandroidserver):

的线程 Thread mThread = new Thread("InputDeviceReader") 本地调用：

readEvent(ev);读取按键。readEvent 调用的是文件：

com_android_server_KeyInputQueue.cpp (frameworksaseservicesjni)中的函数：

static jboolean android_server_KeyInputQueue_readEvent(JNIEnv* env, jobject clazz,

jobject event)