Android onInterceptTouchEvent与onTouchEvent调用关系

概述

onInterceptTouchEvent()是用来拦截Touch事件，ViewGroup有，View没有，onTouchEvent()是Touch事件，ViewGroup与View都有。

实例讲解

当一个Touch事件发生后，会由父布局开始依次执行onInterceptTouchEvent()，如果都没有拦截，则一直往下传，直到底层的View，调用onTouchEvent()，如果一直没有消费，则再依次往上传。



自定义Layout:

package com.whu.touchevent;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.LinearLayout;

/**
* Created by Fly on 2016/10/26.
*/
public class MyLayout extends LinearLayout{
private static final String TAG = "MyLayout";

public MyLayout(Context context) {
super(context);
}

public MyLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
switch (ev.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(TAG, "onInterceptTouchEvent: " + "action down");
break;
case MotionEvent.ACTION_MOVE:
Log.i(TAG, "onInterceptTouchEvent: " + "action move");
case MotionEvent.ACTION_UP:
Log.i(TAG, "onInterceptTouchEvent: " + "action up");
break;
}
return false;
}

@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()){

4000
case MotionEvent.ACTION_DOWN:
Log.i(TAG, "onTouchEvent: " + "action down");
break;
case MotionEvent.ACTION_MOVE:
Log.i(TAG, "onTouchEvent: " + "action move");
break;
case MotionEvent.ACTION_UP:
Log.i(TAG, "onTouchEvent: " + "action up");
break;
}
return false;
}
}

自定义View：

package com.whu.touchevent;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.Button;

/**
* Created by Fly on 2016/10/26.
*/
public class MyView extends Button{
private static final String TAG = "MyView";
public MyView(Context context) {
super(context);
}

public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(TAG, "onTouchEvent: " + "action down");
break;
case MotionEvent.ACTION_MOVE:
Log.i(TAG, "onTouchEvent: " + "action move");
break;
case MotionEvent.ACTION_UP:
Log.i(TAG, "onTouchEvent: " + "action up");
break;
}
return true;
}
}

layout的onInterceptTouchEvent和onTouchEvent都返回false，view的onTouchEvent返回false

10-26 15:33:43.241 4897-4897/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action down
10-26 15:33:43.241 4897-4897/com.whu.touchevent I/MyView: onTouchEvent: action down
10-26 15:33:43.241 4897-4897/com.whu.touchevent I/MyLayout: onTouchEvent: action down

layout没有拦截，走到view的ontouch，view没有消费，继续走，走到layout的ontouch，依然没有消费，继续向上。

2. layout的onInterceptTouchEvent和onTouchEvent都返回false，view的onTouchEvent返回true

10-26 15:38:42.885 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action down
10-26 15:38:42.885 11983-11983/com.whu.touchevent I/MyView: onTouchEvent: action down
10-26 15:38:42.933 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action move
10-26 15:38:42.933 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action up
10-26 15:38:42.933 11983-11983/com.whu.touchevent I/MyView: onTouchEvent: action move
10-26 15:38:42.949 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action move
10-26 15:38:42.949 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action up
10-26 15:38:42.949 11983-11983/com.whu.touchevent I/MyView: onTouchEvent: action move
10-26 15:38:42.957 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action move
10-26 15:38:42.957 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action up
10-26 15:38:42.957 11983-11983/com.whu.touchevent I/MyView: onTouchEvent: action move
10-26 15:38:42.965 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action move
10-26 15:38:42.965 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action up
10-26 15:38:42.965 11983-11983/com.whu.touchevent I/MyView: onTouchEvent: action move
10-26 15:38:42.966 11983-11983/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action up
10-26 15:38:42.966 11983-11983/com.whu.touchevent I/MyView: onTouchEvent: action up

可以看到，如果view消费了这个touch（onTouchEvent返回true），则每次都会像父布局的onInterceptTouchEvent判断是否拦截了。

3. layout的onInterceptTouchEvent返回true，layout的onTouchEvent返回false

10-26 15:41:13.790 20170-20170/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action down
10-26 15:41:13.790 20170-20170/com.whu.touchevent I/MyLayout: onTouchEvent: action down

拦截了后就不会向View传递了，但是并没有消费，所以只有down事件传递进去

4. layout的onInterceptTouchEvent和onTouchEvent都返回true

10-26 15:43:34.204 25353-25353/com.whu.touchevent I/MyLayout: onInterceptTouchEvent: action down
10-26 15:43:34.204 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action down
10-26 15:43:34.272 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action move
10-26 15:43:34.287 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action move
10-26 15:43:34.295 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action move
10-26 15:43:34.304 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action move
10-26 15:43:34.312 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action move
10-26 15:43:34.320 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action move
10-26 15:43:34.320 25353-25353/com.whu.touchevent I/MyLayout: onTouchEvent: action up

拦截并且消费，则down、move、up都被消费。