一、onTouch
onTouch是View中OnTouchListener接口中的方法，处理View及其子类被touch是的事件处理。当然，前提是touch时间能够传递到指定的view。Q1：为什么会传递不到呢？
/**
* Interface definition for a callback to be invoked when a touch event is
* dispatched to this view. The callback will be invoked before the touch
* event is given to the view.
*/
public interface OnTouchListener {
/**
* Called when a touch event is dispatched to a view. This allows listeners to
* get a chance to respond before the target view.
*
* @param v The view the touch event has been dispatched to.
* @param event The MotionEvent object containing full information about
*the event.
* @return True if the listener has consumed the event, false otherwise.
*/
boolean onTouch(View v, MotionEvent event);
}
二、onTouchEvent
onTouchEvent同样也是在view中定义的一个方法。处理传递到view 的手势事件。手势事件类型包括ACTION_DOWN,ACTION_MOVE,ACTION_UP,ACTION_CANCEL四种事件。
/**
* Implement this method to handle touch screen motion events.
*
* @param event The motion event.
* @return True if the event was handled, false otherwise.
*/
public boolean onTouchEvent(MotionEvent event) {
}
一旦onTouchEvent方法被调用，并返回true则这个手势事件就结束了，并不会向下传递到子控件。Q2：onTouchEvent什么时候被调用呢？
三、onInterceptTouchEvent
onInterceptTouchEvent是在ViewGroup里面定义的。Android中的layout布局类一般都是继承此类的。 onInterceptTouchEvent是用于拦截手势事件的，每个手势事件都会先调用onInterceptTouchEvent。
public boolean onInterceptTouchEvent(MotionEvent ev) {
return false;
}
此方法返回false，则手势事件会向子控件传递；返回true，则调用onTouchEvent方法。
