Android触摸事件的分发机制

---恢复内容开始---

一、MotionEvent : ACTION_DOWN（下按事件）、ACTION_UP（松开事件）、ACTION_MOVE（移动事件）

二、三大函数

1.dispatchTouchEvent(Event event) == > 分发函数，由系统自动调用（返回值为true时，viewGroup可以向其子控件分发事件，view则分发给自身）

public boolean dispatchTouchEvent(MotionEvent ev) {
        int action = ev.getAction();
        switch(action){
            case MotionEvent.ACTION_DOWN:
                Log.e("MyLinearLayout2", "dispatchTouchEvent-->ACTION_DOWN");
                break;
            case MotionEvent.ACTION_MOVE:
                Log.e("MyLinearLayout2","dispatchTouchEvent-->ACTION_MOVE");
                break;
            case MotionEvent.ACTION_UP:
                Log.e("MyLinearLayout2","dispatchTouchEvent-->ACTION_UP");
                break;
        }
        return super.dispatchTouchEvent(ev);

}

2.onInterceptTouchEvent(Event event) ==> 拦截函数（viewGroup有，view没有）

a.返回值为true时，viewGroup对象会将事件拦截，使得之后的UP和MOVE不会被任何控件相应;

b.返回值为false时，viewGroup不拦截事件，事件可以正常分发。

public boolean onInterceptTouchEvent(MotionEvent ev) {

        int action = ev.getAction();
        switch(action){
            case MotionEvent.ACTION_DOWN:
                Log.e("MyLInearLayout","onInterceptTouchEvent-->ACTION_DOWN");
                break;
            case MotionEvent.ACTION_MOVE:
                Log.e("MyLInearLayout","onInterceptTouchEvent-->ACTION_MOVE");
                break;
            case MotionEvent.ACTION_UP:
                Log.e("MyLInearLayout","onInterceptTouchEvent-->ACTION_UP");
                break;
        }
        return false;
    }

3.onTouchEvent(Event event) == >触摸相应函数

a.事件逐级向下传递，直到某个view或viewGroup执行onTouchEvent，若返回值为false，则会通知其父viewGroup执行onTouchEvent,若返回值为true，则不通知其父viewGroup执行onTouchEvent;

b.当某个view或viewGroup的onTouchEvent（）相应，并且返回值为true时，之后的MOVE和UP的响应事件都会直接传递给该空间，并由该控件的onTouchEvent()响应；

直接上代码：

MainActivity:

 1 package com.example.qjm3662.myapplication;
 2 
 3 import android.app.Activity;
 4 import android.content.Context;
 5 import android.os.Bundle;
 6 import android.support.design.widget.FloatingActionButton;
 7 import android.support.design.widget.Snackbar;
 8 import android.support.v7.app.AppCompatActivity;
 9 import android.support.v7.widget.Toolbar;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.widget.LinearLayout;
 
 public class MainActivity extends Activity{
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
     }

25 }

MyLInearLayout:

 1 package com.example.qjm3662.myapplication;
 2 
 3 import android.content.Context;
 4 import android.util.AttributeSet;
 5 import android.util.Log;
 6 import android.view.MotionEvent;
 7 import android.widget.LinearLayout;
 8 
 9 /**
  * Created by qjm3662 on 2016/4/10 0010.
  */
 public class MyLInearLayout extends LinearLayout {
     public MyLInearLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
     @Override
     public boolean dispatchTouchEvent(MotionEvent ev) {
         int action = ev.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("MyLInearLayout","dispatchTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("MyLInearLayout","dispatchTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("MyLInearLayout","dispatchTouchEvent-->ACTION_UP");
                 break;
         }
         return super.dispatchTouchEvent(ev);
     }
 
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         int action = event.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("MyLInearLayout","onTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("MyLInearLayout","onTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("MyLInearLayout","onTouchEvent-->ACTION_UP");
                 break;
         }
         return false;
     }
 
     @Override
     public boolean onInterceptTouchEvent(MotionEvent ev) {
 
         int action = ev.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("MyLInearLayout","onInterceptTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("MyLInearLayout","onInterceptTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("MyLInearLayout","onInterceptTouchEvent-->ACTION_UP");
                 break;
         }
         return false;
     }
 

69 }

MyLinearLayout2:

 1 package com.example.qjm3662.myapplication;
 2 
 3 import android.content.Context;
 4 import android.util.AttributeSet;
 5 import android.util.Log;
 6 import android.view.MotionEvent;
 7 import android.widget.LinearLayout;
 8 
 9 /**
  * Created by qjm3662 on 2016/4/10 0010.
  */
 public class MyLinearLayout2 extends LinearLayout{
     public MyLinearLayout2(Context context) {
         super(context);
     }
 
     public MyLinearLayout2(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
     public MyLinearLayout2(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
     }
 
     @Override
     public boolean dispatchTouchEvent(MotionEvent ev) {
         int action = ev.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("MyLinearLayout2", "dispatchTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("MyLinearLayout2","dispatchTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("MyLinearLayout2","dispatchTouchEvent-->ACTION_UP");
                 break;
         }
         return super.dispatchTouchEvent(ev);
     }
 
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         int action = event.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("MyLinearLayout2","onTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("MyLinearLayout2","onTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("MyLinearLayout2","onTouchEvent-->ACTION_UP");
                 break;
         }
         return false;
     }
 
     @Override
     public boolean onInterceptTouchEvent(MotionEvent ev) {
 
         int action = ev.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("MyLinearLayout2","onInterceptTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("MyLinearLayout2","onInterceptTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("MyLinearLayout2","onInterceptTouchEvent-->ACTION_UP");
                 break;
         }
         return true;
     }

76 }

view:

 1 package com.example.qjm3662.myapplication;
 2 
 3 import android.content.Context;
 4 import android.util.AttributeSet;
 5 import android.util.Log;
 6 import android.view.MotionEvent;
 7 import android.widget.TextView;
 8 
 9 /**
  * Created by qjm3662 on 2016/4/10 0010.
  */
 public class view extends TextView{
 
 
     public view(Context context) {
         super(context);
     }
 
     public view(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
     public view(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
     }
 
 
     @Override
     public boolean dispatchTouchEvent(MotionEvent ev) {
         int action = ev.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("view","dispatchTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("view","dispatchTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("view","dispatchTouchEvent-->ACTION_UP");
                 break;
         }
         return super.dispatchTouchEvent(ev);
     }
 
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         int action = event.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("view","onTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("view","onTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("view","onTouchEvent-->ACTION_UP");
                 break;
         }
         return true;
     }
 
 
 }

view2:

 1 package com.example.qjm3662.myapplication;
 2 
 3 import android.content.Context;
 4 import android.util.AttributeSet;
 5 import android.util.Log;
 6 import android.view.MotionEvent;
 7 import android.widget.ImageView;
 8 
 9 /**
  * Created by qjm3662 on 2016/4/10 0010.
  */
 public class view2 extends ImageView{
     public view2(Context context) {
         super(context);
     }
 
     public view2(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
     public view2(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
     }
 
     @Override
     public boolean dispatchTouchEvent(MotionEvent event) {
         int action = event.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("view2", "dispatchTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("view2","dispatchTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("view2","dispatchTouchEvent-->ACTION_UP");
                 break;
         }
         return super.dispatchTouchEvent(event);
     }
 
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         int action = event.getAction();
         switch(action){
             case MotionEvent.ACTION_DOWN:
                 Log.e("view2","onTouchEvent-->ACTION_DOWN");
                 break;
             case MotionEvent.ACTION_MOVE:
                 Log.e("view2","onTouchEvent-->ACTION_MOVE");
                 break;
             case MotionEvent.ACTION_UP:
                 Log.e("view2","onTouchEvent-->ACTION_UP");
                 break;
         }
         return false;
     }

58 }

布局：

<?xml version="1.0" encoding="utf-8"?>
<com.example.qjm3662.myapplication.MyLInearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <com.example.qjm3662.myapplication.view
        android:text="dsvsdvsvsdv"
        android:textSize="24sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <com.example.qjm3662.myapplication.MyLinearLayout2
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:orientation="vertical"
        >
        <com.example.qjm3662.myapplication.view2
            android:src="@drawable/ic_launcher"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </com.example.qjm3662.myapplication.MyLinearLayout2>

</com.example.qjm3662.myapplication.MyLInearLayout>

运行结果：

点击上面的TextView后松开：

04-10 06:42:32.234 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: dispatchTouchEvent-->ACTION_DOWN
04-10 06:42:32.234 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: onInterceptTouchEvent-->ACTION_DOWN
04-10 06:42:32.234 2414-2414/com.example.qjm3662.myapplication E/view: dispatchTouchEvent-->ACTION_DOWN
04-10 06:42:32.234 2414-2414/com.example.qjm3662.myapplication E/view: onTouchEvent-->ACTION_DOWN
04-10 06:42:32.474 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: dispatchTouchEvent-->ACTION_UP
04-10 06:42:32.474 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: onInterceptTouchEvent-->ACTION_UP
04-10 06:42:32.474 2414-2414/com.example.qjm3662.myapplication E/view: dispatchTouchEvent-->ACTION_UP
04-10 06:42:32.474 2414-2414/com.example.qjm3662.myapplication E/view: onTouchEvent-->ACTION_UP

点击下面的ImagView后松开：

04-10 06:43:58.322 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: dispatchTouchEvent-->ACTION_DOWN
04-10 06:43:58.322 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: onInterceptTouchEvent-->ACTION_DOWN
04-10 06:43:58.322 2414-2414/com.example.qjm3662.myapplication E/MyLinearLayout2: dispatchTouchEvent-->ACTION_DOWN
04-10 06:43:58.322 2414-2414/com.example.qjm3662.myapplication E/MyLinearLayout2: onInterceptTouchEvent-->ACTION_DOWN
04-10 06:43:58.322 2414-2414/com.example.qjm3662.myapplication E/MyLinearLayout2: onTouchEvent-->ACTION_DOWN

04-10 06:43:58.322 2414-2414/com.example.qjm3662.myapplication E/MyLInearLayout: onTouchEvent-->ACTION_DOWN