A View's onTouchListener vs onTouchEvent

问题:

What is the difference between a view's onTouchEvent :

public class MyCustomView extends View {
    // THIS :
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return super.onTouchEvent(event);
    }
}

and its onTouchListener :

MyCustomView myView = (MyCustomView) findViewById(R.id.customview);
myView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public void onClick(View arg0) {
        // do something
    }
});

or

public class MyCustomView extends View {

    public MyCustomView(Context context, AttributeSet attrs) {
        // THIS :
        setOnTouchListener(new View.OnTouchListener() {
            @Override
            public void onClick(View arg0) {
                // do something
            }
        });
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return super.onTouchEvent(event);
    }
}

If this two is different,
Do we need to implement both ?
Which one is invoked first ?

If I have some scrolling and zooming functionality, should I implement them inside onTouchEvent or onTouchListener ?

回答1:

Answer by LeeYiHong is correct, and the other very important thing is what is written at http://developer.android.com/reference/android/view/View.OnTouchListener.html:

The callback [i.e. View.OnTouchListener -> onTouch(View v, MotionEvent event)] will be invoked before the touch event [i.e. onTouchEvent(MotionEvent)] is given to the view.

回答2:

I am not sure if you had found your answer. But I found related questions similar to yours.

"onTouch works everywhere you want (whether it is in activity or view) as long as you have declared the interface and put the Listener right! On the other hand, onTouchEvent only works inside a View!"

For scrolling and zooming functionality, I guess onTouchListener will be enough to complete both function (and many more like rotation etc).