源码分析安卓事件分发机制的流程

1、Activity---dispatchTouchEvent(MotionEvent ev)----这是APP的点击事件入口，用户的点击操作都是从activity的dispatchTouchEvent方法开始的。

某个activity

MainActivity
@Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        return super.dispatchTouchEvent(ev);
    }

2、activity 的dispatchTouchEvent()方法的源码，最终走getWindow().superDispatchTouchEvent(ev)方法。getWindow()这个方法，返回mWindow，是Window的实例，Window 是抽象类，唯一实例是PhoneWindow

activity
/**
     * Called to process touch screen events.  You can override this to
     * intercept all touch screen events before they are dispatched to the
     * window.  Be sure to call this implementation for touch screen events
     * that should be handled normally.
     *
     * @param ev The touch screen event.
     *
     * @return boolean Return true if this event was consumed.
     */
    public boolean dispatchTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            //空方法
            onUserInteraction();
        }
        if (getWindow().superDispatchTouchEvent(ev)) {
            return true;
        }
        return onTouchEvent(ev);
    }

3、再看PhoneWindow类中的superDispatchTouchEvent方法，最终走的mDecor的superDispatchTouchEvent，这个mDecor是DecorWindow的实例，DecorWindow是是FrameLayout的子类，最终也就走入到了viewgroup的DispatchTouchEvent方法了。

com.android.internal.policy.PhoneWindow
@Override
    public boolean superDispatchTouchEvent(MotionEvent event) {
        return mDecor.superDispatchTouchEvent(event);
        //mDecor 是DecorView的实例
    }

com.android.internal.policy.DecorWindow 是FrameLayout的子类
public class DecorView extends FrameLayout implements RootViewSurfaceTaker, WindowCallbacks {
public boolean superDispatchTouchEvent(MotionEvent event) {
        return super.dispatchTouchEvent(event);
        //实际上执行的是ViewGroup的dispatchTouchEvent（）方法
    }
    }

4、接着看viewgroup的dispatchTouchEvent分发，到这里大家基本都了解了，viewgroup会遍历包含的view，执行view的dispatchTouchEvent，这一部分的知识网上太多了，就不看源码了，想了解的自行百度。基本流程看图即可。

view的事件分发：

源码分析安卓事件分发机制的流程

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