在 APP 中，触摸/点击是一个非常频繁的交互；当控件区域重叠时，想要达到满意的效果，就需要把 Touch 的相关事件理解透彻。

相关方法：

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dispatchTouchEvent(MotionEvent ev) // 事件分发
onInterceptTouchEvent(MotionEvent ev) // 事件拦截
onTouchEvent(MotionEvent ev) // 事件响应

其中 ViewGroup 包含以上3个方法，View 不包含onInterceptTouchEvent（毕竟 View 已经是视图控件的最小单元了，无需拦截）。

Touch 事件分析

事件分发：public boolean dispatchTouchEvent(MotionEvent ev)

Father->Child 的传递顺序

  • return true时，touch事件终结于此，并停止向下传递

事件拦截：public boolean onInterceptTouchEvent(MotionEvent ev)

  • return true时，则表示将事件进行拦截，子View不再处理Touch事件

事件响应：public boolean onTouchEvent(MotionEvent ev)

Child-> Father 的顺序，若中途被消费，父控件不再执行onTouchEvent。

  • return true 则会接收并消费该事件。

DEMO

重写 ViewGroup和View

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public class FatherView extends RelativeLayout 
{
    public FatherView(Context context) {
        super(context);
    }

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

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
    	boolean ret = super.dispatchTouchEvent(ev);
    	Log.i("TouchDemo", getTag() + " - " + "dispatchTouchEvent: " + ret);
        return ret;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
    	boolean ret = super.onInterceptTouchEvent(ev);
    	Log.i("TouchDemo", getTag() + " - " + "onInterceptTouchEvent: " + ret);
        return ret;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
    	boolean ret = super.onTouchEvent(ev);
    	Log.i("TouchDemo", getTag() + " - " + "onTouchEvent: " + ret);
        return ret;
    }
}
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public class ChildView extends View 
{
    public ChildView(Context context) {
        super(context);
    }

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

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
    	boolean ret = super.dispatchTouchEvent(ev);
    	Log.i("TouchDemo", getTag() + " - " + "dispatchTouchEvent: " + ret);
        return ret;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
    	boolean ret = super.onTouchEvent(ev);
    	Log.i("TouchDemo", getTag() + " - " + "onTouchEvent: " + ret);
        return ret;
    }
}

布局文件

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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:gif="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#c1e1f8" >

    <com.fangqk.touchdemo.FatherView 
	    android:layout_width="200dp"
	    android:layout_height="200dp"
		android:layout_centerInParent="true"
	    android:background="#ffffff"
		android:tag="Father" >
	
        <com.fangqk.touchdemo.ChildView 
		    android:layout_width="150dp"
		    android:layout_height="100dp"
		    android:layout_centerVertical="true"
		    android:background="#88ff0000"
		    android:tag="Child-1" />
        <com.fangqk.touchdemo.ChildView 
		    android:layout_width="150dp"
		    android:layout_height="100dp"
		    android:layout_centerVertical="true"
		    android:layout_alignParentRight="true"
		    android:background="#8800ff00"
		    android:tag="Child-2" />
	</com.fangqk.touchdemo.FatherView>
</RelativeLayout>

说明


预览图中，白色区域是Father，红色区域是Child-1，绿色区域是Child-2。

点击白色区域时

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# 默认状态
Father - onInterceptTouchEvent: false
Father - onTouchEvent: false
Father - dispatchTouchEvent: false

点击红色区域时

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# 默认状态
Father - onInterceptTouchEvent: false
Child-1 - onTouchEvent: false
Child-1 - dispatchTouchEvent: false
Father - onTouchEvent: false
Father - dispatchTouchEvent: false

# 使 Father 的 dispatchTouchEvent返回true时
# 不再执行其余响应操作 
Father - dispatchTouchEvent: true
Father - dispatchTouchEvent: true

# 使 Father 的 dispatchTouchEvent返回true时
# 不再向Child传递Touch事件 
Father - onInterceptTouchEvent: true
Father - onTouchEvent: false
Father - dispatchTouchEvent: false

# 使 Child 的 onTouchEvent返回true时
# Father 的onTouchEvent不再执行
Father - onInterceptTouchEvent: false
Child-1 - onTouchEvent: true
Child-1 - dispatchTouchEvent: true
Father - dispatchTouchEvent: true
Father - onInterceptTouchEvent: false
Child-1 - onTouchEvent: true
Child-1 - dispatchTouchEvent: true
Father - dispatchTouchEvent: true

点击红绿重叠区域时

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# 默认状态
Father - onInterceptTouchEvent: false
Child-2 - onTouchEvent: false
Child-2 - dispatchTouchEvent: false
Child-1 - onTouchEvent: false
Child-1 - dispatchTouchEvent: false
Father - onTouchEvent: false
Father - dispatchTouchEvent: false

关于同级 View 重叠的问题，未来再做探讨

参考链接:
http://www.cnblogs.com/sunzn/archive/2013/05/10/3064129.html
https://developer.android.com/training/gestures/viewgroup.html