事件拦截机制
声明：对事件拦截机制的详细了解，除了群英传上的部分以外，还涵盖了开发艺术探索这本书上的内容，在开发艺术探索这本书上称之为事件分发机制。
什么是事件拦截机制？要了解事件拦截机制，首先要了解触摸事件。
触摸事件就是捕获触摸屏幕后产生的事件，Android为触摸事件封装了一个类——MotionEvent。当点击屏幕通常会产生两或三个事件——按下（MotionEvent.ACTION_DOWN），滑动（MotionEvent.ACTION_MOVE），抬起手（MotionEvent.ACTION_UP）。重写onTouchEvent()方法，其参数就是MotionEvent，只要是重写触摸相关的方法，参数一般都含有MotionEvent，可见其重要性。
而所谓的事件拦截机制，其实就是对MotionEvent事件的拦截和分发过程，即当一个MotionEvent产生了以后，系统需要把这个事件传递给具体的View，而这个过程就是事件的拦截和分发过程。要完成这个过程需要三个很重要的方法来共同完成：dispatchTouchEvent、onInterceptTouchEvent和onTouchEvent，先来介绍下这几个方法吧！
public boolean dispatchTouchEvent(MotionEvent ev)
用来进行事件的分发。如果事件能够传递给当前View，那么此方法一定会被调用，返回结果受当前View的onTouchEvent和下级View的dispatchTouchEvent方法的影响，表示是否消耗当前事件。
public boolean onInterceptTouchEvent(MotionEvent event)
在上述方法内部调用，用来判断是否拦截某个事件，如果当前View拦截某个事件，那么在同一个事件序列当中，此方法不会被再次调用，返回结果表示是否拦截当前事件。
public boolean onTouchEvent(MotionEvent event)
在dispatchTouchEvent方法中调用，用来处理点击事件，返回结果表示是否消耗当前事件，如果不消耗，则在同一个事件序列中，当前View无法再次接收到事件。
它们的关系？请看以下的伪代码：
public boolean dispatchTouchEvent(MotionEvent ev) {
boolean consume = false;
if(onInterceptTouchEvent(ev)) {
consume = onTouchEvent(ev);
} else {
consume = child.dispatchTouchEvent(ev);
}
return consume;
}
通过以上伪代码我们可以知道点击事件的传递规则：
对于一个根ViewGroup来说，点击事件产生后，首先会传递给它，这时它的dispatchTouchEvent就会被调用，如果这个ViewGroup的onInterceptTouchEvent方法返回true就表示它要拦截当前事件，接着事件就会交给这个ViewGroup处理，即它的onTouchEvent方法就会被调用；如果这个ViewGroup的onInterceptTouchEvent方法返回false就表示它不拦截当前事件，这时当前事件就会继续传递给它的子元素，接着子元素的dispatchTouchEvent方法就会被调用，如此反复知道事件被最终处理。
在以上理论的基础上进行进一步的实践，其实实践过程非常简单，就是重写了事件拦截和处理的几个方法，并通过log的方式观察几个方法的执行过程。
完成实践需要两个ViewGroup和一个View，分别给它们命名，最外层的ViewGroup为MyViewGroupA，中间ViewGroup为MyViewGroupB，最底层的View为MyView。本例的整个布局如图所示：
对于ViewGroup来说，重写了如下所示的三个方法：
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
Log.i(TAG, "MyViewGroupA_dispatchTouchEvent: " + ev.getAction());
boolean result = super.dispatchTouchEvent(ev);
Log.i(TAG, "MyViewGroupA_dispatchTouchEvent_after: " + result);
return result;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
Log.i(TAG, "MyViewGroupA_onInterceptTouchEvent: " + ev.getAction());
boolean result = super.onInterceptTouchEvent(ev);
Log.i(TAG, "MyViewGroupA_onInterceptTouchEvent_after: " + result);
return result;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyViewGroupA_onTouchEvent: " + event.getAction());
boolean result = super.onTouchEvent(event);
Log.i(TAG, "MyViewGroupA_onTouchEvent_after: " + result);
return result;
}
而对于View来说，重写了如下所示的两个方法：
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyView_onTouchEvent: " + event.getAction());
boolean result = super.onTouchEvent(event);
Log.i(TAG, "MyView_onTouchEvent_after: " + result);
return result;
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
Log.i(TAG, "MyView_dispatchTouchEvent: " + event.getAction());
boolean result = super.dispatchTouchEvent(event);
Log.i(TAG, "MyView_dispatchTouchEvent_after: " + result);
return result;
}
首先不修改任何值，只是点击一下View，然后看Log会怎样记录我们的操作和程序的响应。
10-08 02:32:46.216 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent: 0
10-08 02:32:46.216 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent: 0
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent_after: false
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent: 0
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent: 0
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent_after: false
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent: 0
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent: 0
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent_after: false
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent_after: false
10-08 02:32:46.217 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent: 0
10-08 02:32:46.218 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent_after: false
10-08 02:32:46.218 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent_after: false
10-08 02:32:46.218 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onTouchEvent: 0
10-08 02:32:46.218 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onTouchEvent_after: false
10-08 02:32:46.218 8213-8213/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent_after: false
可见，正常情况下，事件的传递顺序是：
MyViewGroupA ——> MyViewGroupB ——> View
传递时先执行dispatchTouchEvent()方法，再执行onInterceptTouchEvent()方法。
事件的处理顺序是：
View ——> MyViewGroupA ——> MyViewGroupB
处理时都是执行onTouchEvent()方法。
这个日志也证实了伪代码的准确性。
可以将上面的整个事件过程整理成如图：
那么假设MyViewGroupB将事件拦截住了呢？会不会就是不执行MyView的相关事件方法呢？让我们试试给MyViewGroupB的onInterceptTouchEvent()方法返回true看看。
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent: 0
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent: 0
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent_after: false
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent: 0
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent: 0
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent_after: true
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent: 0
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent_after: false
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent_after: false
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onTouchEvent: 0
10-08 02:59:34.694 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onTouchEvent_after: false
10-08 02:59:34.695 31295-31295/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent_after: false
和设想一样，MyView没事可干了。那么如果MyView处理事件时直接返回true，会怎么样呢？
修改MyView的代码如下所示：
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyView_onTouchEvent: " + event.getAction());
super.onTouchEvent(event);
Log.i(TAG, "MyView_onTouchEvent_after: " + true);
return true;
}
再来看看Log，如下所示：
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent: 0
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent: 0
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent_after: false
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent: 0
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent: 0
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent_after: false
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent: 0
10-08 05:53:24.361 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent: 0
10-08 05:53:24.362 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent_after: true
10-08 05:53:24.362 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent_after: true
10-08 05:53:24.362 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent_after: true
10-08 05:53:24.362 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent_after: true
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent: 1
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent: 1
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent_after: false
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent: 1
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent: 1
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent_after: false
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent: 1
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent: 1
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent_after: true
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent_after: true
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent_after: true
10-08 05:53:24.442 2634-2634/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent_after: true
这里会发现处理的过程好像变的更长了，其实这里给MyView的点击事件返回true就表示消耗了事件，就如上面介绍onTouchEvent方法时所描述的，消耗了就开始接收下次的事件。相信读者已经注意到了Log日志中getAction()返回的数值，那么这些数值代表着什么呢？
其实0表示ACTION_DOWN事件，1表示ACTION_UP事件，2表示ACTION_MOVE事件。
结合这些要点，在看面的Log日志，发现在执行ACTION_DOWN事件时，MyView的onTouchEvent方法返回true后，两个ViewGroup都不执行onTouchEvent方法，这也就是说MyView直接结束了这次事件，不再传回两个ViewGroup。但是，在结束了ACTION_DOWN事件后，紧接着开始执行了ACTION_UP事件，说明只有当MyView的onTouchEvent返回true才会执行下面的事件。
那么，恢复原代码后修改MyViewGroupB内的onTouchEvent返回值为true：
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyViewGroupB_onTouchEvent: " + event.getAction());
super.onTouchEvent(event);
Log.i(TAG, "MyViewGroupB_onTouchEvent_after: " + true);
return true;
}
现在再来观察Log日志文件：
10-08 06:31:49.333 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent: 0
10-08 06:31:49.333 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent: 0
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent_after: false
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent: 0
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent: 0
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onInterceptTouchEvent_after: false
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent: 0
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent: 0
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_onTouchEvent_after: false
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyView_dispatchTouchEvent_after: false
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent: 0
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent_after: true
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent_after: true
10-08 06:31:49.334 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent_after: true
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent: 1
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent: 1
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_onInterceptTouchEvent_after: false
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent: 1
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent: 1
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_onTouchEvent_after: true
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupB_dispatchTouchEvent_after: true
10-08 06:31:49.421 9604-9604/com.example.eventinterceptionmechanism I/TestViewAndViewGroup: MyViewGroupA_dispatchTouchEvent_after: true
我们会发现结果和修改MyView的onTouchEvent方法的结果是一样的，也是返回true后直接结束事件，但是在第二次处理事件的时候，MyView就没再参与事件的处理，也就是说一旦onTouchEvent返回值为false就会导致在本次处理过程中后面的事件将不再分发给该View。
通过上面的分析，相信对事件的拦截，分发和处理有了一定的了解。
代码
那么最后再贴上测试的源代码：
MyViewGroupA.java
package com.example.eventinterceptionmechanism;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.LinearLayout;
/**
* MyViewGroupA
* Created by shize on 2016/10/7.
*/
public class MyViewGroupA extends LinearLayout {
private final static String TAG = "TestViewAndViewGroup";
public MyViewGroupA(Context context) {
super(context);
}
public MyViewGroupA(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyViewGroupA(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
Log.i(TAG, "MyViewGroupA_dispatchTouchEvent: " + ev.getAction());
boolean result = super.dispatchTouchEvent(ev);
Log.i(TAG, "MyViewGroupA_dispatchTouchEvent_after: " + result);
return result;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
Log.i(TAG, "MyViewGroupA_onInterceptTouchEvent: " + ev.getAction());
boolean result = super.onInterceptTouchEvent(ev);
Log.i(TAG, "MyViewGroupA_onInterceptTouchEvent_after: " + result);
return result;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyViewGroupA_onTouchEvent: " + event.getAction());
boolean result = super.onTouchEvent(event);
Log.i(TAG, "MyViewGroupA_onTouchEvent_after: " + result);
return result;
}
}
MyViewGroupB.java
package com.example.eventinterceptionmechanism;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.LinearLayout;
/**
* MyViewGroupB
* Created by shize on 2016/10/7.
*/
public class MyViewGroupB extends LinearLayout {
private final static String TAG = "TestViewAndViewGroup";
public MyViewGroupB(Context context) {
super(context);
}
public MyViewGroupB(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyViewGroupB(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
Log.i(TAG, "MyViewGroupB_dispatchTouchEvent: " + ev.getAction());
boolean result = super.dispatchTouchEvent(ev);
Log.i(TAG, "MyViewGroupB_dispatchTouchEvent_after: " + result);
return result;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
Log.i(TAG, "MyViewGroupB_onInterceptTouchEvent: " + ev.getAction());
boolean result = super.onInterceptTouchEvent(ev);
Log.i(TAG, "MyViewGroupB_onInterceptTouchEvent_after: " + result);
return result;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyViewGroupB_onTouchEvent: " + event.getAction());
boolean result = super.onTouchEvent(event);
Log.i(TAG, "MyViewGroupB_onTouchEvent_after: " + result);
return result;
}
}
MyView.java
package com.example.eventinterceptionmechanism;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.TextView;
/**
* MyView
* Created by shize on 2016/10/7.
*/
public class MyView extends TextView {
private final static String TAG = "TestViewAndViewGroup";
public MyView(Context context) {
super(context);
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.i(TAG, "MyView_onTouchEvent: " + event.getAction());
boolean result = super.onTouchEvent(event);
Log.i(TAG, "MyView_onTouchEvent_after: " + result);
return result;
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
Log.i(TAG, "MyView_dispatchTouchEvent: " + event.getAction());
boolean result = super.dispatchTouchEvent(event);
Log.i(TAG, "MyView_dispatchTouchEvent_after: " + result);
return result;
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<com.example.eventinterceptionmechanism.MyViewGroupA xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center_horizontal"
tools:context="com.example.eventinterceptionmechanism.MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="80dp"
android:textSize="24sp"
android:textAlignment="center"
android:text="@string/view_group_a"
android:textColor="@color/back"/>
<com.example.eventinterceptionmechanism.MyViewGroupB
android:layout_width="380dp"
android:layout_height="450dp"
android:orientation="vertical"
android:background="@color/back"
android:gravity="center_horizontal">
<TextView
android:layout_width="match_parent"
android:layout_height="120dp"
android:textSize="24sp"
android:textAlignment="center"
android:text="@string/view_group_b"
android:textColor="@color/write"/>
<com.example.eventinterceptionmechanism.MyView
android:layout_width="300dp"
android:layout_height="200dp"
android:textSize="24sp"
android:textAlignment="center"
android:text="@string/my_view"
android:background="@color/blue"
android:textColor="@color/write"/>
</com.example.eventinterceptionmechanism.MyViewGroupB>
</com.example.eventinterceptionmechanism.MyViewGroupA>
感谢阅读，学习重在坚持，贵在坚持，那么下次再见。
