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View的事件传递机制

2017-03-17 18:41 302 查看

1.事件的传递过程

首先由Activity分发，分发给根View，也就是DecorView（DecorView为整个Window界面的最顶层View）。然后由根View分发到子的ViewGroup，再由各个ViewGroup分发给子View

（1）当我们点击viewC时，就会触发事件，然后事件传递给viewgroupA，viewgroupA它首先会执行dispatchTouchEvent来调用onInterceptTouchEvent判断本group是否可以处理，return ture则交由onTouchEvent处理事件，return false则使用dispatchTouchEvent往下传递事件。

（2）往下传递过来的事件由viewgroupB的onInterceptTouchEvent拦截，问自己能否处理该事件，能则处理，不能则往下继续传递。同理viewC的这一步流程。

（3）当传递到最终的viewC的时候，如果不能够处理该触发事件，是会重新回传给父控件的

2.View的dispatchTouchEvent和onTouchEvent

探讨Android事件传递机制前，明确android的两大基础控件类型:View和ViewGroup。View即普通的控件，没有子布局的，如Button、TextView. ViewGroup继承自View，表示可以有子控件，如Linearlayout、Listview这些。而事件即MotionEvent，最重要的有3个:

(1)MotionEvent.ACTION_DOWN 按下View，是所有事件的开始
(2)MotionEvent.ACTION_MOVE 滑动事件

(3)MotionEvent.ACTION_UP 与down对应，表示抬起

另外，明确事件传递机制的最终目的都是为了触发执行View的点击监听和触摸监听:
******.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.i(tag, "testLinelayout---onClick...");
}
});

*******.setOnTouchListener(new View.OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub

return false;
}
});

我们简称为onClick监听和onTouch监听，一般程序会注册这两个监听。从上面可以看到，onTouch监听里默认return false。不要小看了这个return false，后面可以看到它有大用。
对于View来说，事件传递机制有两个函数：dispatchTouchEvent负责分发事件，在dispatch***里又会调用onTouchEvent表示执行事件，或者说消费事件，结合源码分析其流程。事件传递的入口是View的dispatchTouchEvent()函数:

/**
* Pass the touch screen motion event down to the target view, or this
* view if it is the target.
*
* @param event The motion event to be dispatched.
* @return True if the event was handled by the view, false otherwise.
*/
public boolean dispatchTouchEvent(MotionEvent event) {
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onTouchEvent(event, 0);
}

if (onFilterTouchEventForSecurity(event)) {
//noinspection SimplifiableIfStatement
ListenerInfo li = mListenerInfo;
if (li != null && li.mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED
&& li.mOnTouchListener.onTouch(this, event)) {
return true;
}

if (onTouchEvent(event)) {
return true;
}
}

if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onUnhandledEvent(event, 0);
}
return false;
}

if (li != null && li.mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED

&& li.mOnTouchListener.onTouch(this, event)) {

return true;

}

他会执行View的OnTouchListener.onTouch这个函数，也就是上面说的onTouch监听。里面有三个判断，如果三个都为1，就会执行return true，不往下走了。而默认的onTouch监听返回false，只要一个是false，就不会返回true。接着往下看，程序执行onTouchEvent：

if (onTouchEvent(event)) {
return true;
}

onTouchEvent的源码比较多:

if (!mHasPerformedLongPress) {
// This is a tap, so remove the longpress check
removeLongPressCallback();

// Only perform take click actions if we were in the pressed state
if (!focusTaken) {
// Use a Runnable and post this rather than calling
// performClick directly. This lets other visual state
// of the view update before click actions start.
if (mPerformClick == null) {
mPerformClick = new PerformClick();
}
if (!post(mPerformClick)) {
<span style="color:#ff0000;"> performClick();</span>
}
}
}

可以看到有个performClick(),它的源码里有这么一句 li.mOnClickListener.onClick(this);

public boolean performClick() {
sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);

ListenerInfo li = mListenerInfo;
if (li != null && li.mOnClickListener != null) {
playSoundEffect(SoundEffectConstants.CLICK);
<span style="color:#ff0000;"><strong>li.mOnClickListener.onClick(this);</strong></span>
return true;
}

return false;
}

终于对上了，它执行了我们注册的onClick监听。当然执行前会经过一系列判断，是否注册了监听等。

总结:

1、事件入口是dispatchTouchEvent(),它会先执行注册的onTouch监听,如果一切顺利的话，接着执行onTouchEvent，在onTouchEvent里会执行onClick监听。
2、无论是dispatchTouchEvent还是onTouchEvent，如果返回true表示这个事件已经被消费、处理了，不再往下传了。在dispathTouchEvent的源码里可以看到，如果onTouchEvent返回了true，那么它也返回true。如果dispatch***在执行onTouch监听的时候，onTouch返回了true，那么它也返回true，这个事件提前被onTouch消费掉了。就不再执行onTouchEvent了，更别说onClick监听了。
3、我们通常在onTouch监听了设置图片一旦被触摸就改变它的背景、透明度之类的，这个onTouch表示事件的时机。而在onClick监听了去具体干某些事。

下面通过代码来说明,自定义一个TestButton继承自Button，重写它的dispath***和onTouchEvent方法，为了简单只关注down和up事件。

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

public class TestButton extends Button {
private final static String tag = "yan";
public TestButton(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "TestButton-onTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "TestButton-onTouchEvent-ACTION_UP...");
break;
default:break;
}
return super.onTouchEvent(event);
}

@Override
public boolean dispatchTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "TestButton-dispatchTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "TestButton-dispatchTouchEvent-ACTION_UP...");
break;
default:break;
}

return super.dispatchTouchEvent(event);
}

}

在Activity里注册两个监听:

testBtn.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.i(tag, "testBtn---onClick...");
}
});
testBtn.setOnTouchListener(new View.OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "testBtn-onTouch-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "testBtn-onTouch-ACTION_UP...");
break;
default:break;

}
return false;
}
});

同时复写Activity的dispatch方法和onTouchEvent方法：

public boolean dispatchTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
switch(ev.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "MainActivity-dispatchTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "MainActivity-dispatchTouchEvent-ACTION_UP...");
break;
default:break;
}
return super.dispatchTouchEvent(ev);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "MainActivity-onTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "MainActivity-onTouchEvent-ACTION_UP...");
break;
default:break;
}
return super.onTouchEvent(event);
}

最终一次点击，打印信息如下:

Line 33: 01-08 14:59:45.847 I/yan ( 4613): MainActivity-dispatchTouchEvent-ACTION_DOWN...
Line 35: 01-08 14:59:45.849 I/yan ( 4613): TestButton-dispatchTouchEvent-ACTION_DOWN...
Line 37: 01-08 14:59:45.849 I/yan ( 4613): testBtn-onTouch-ACTION_DOWN...
Line 39: 01-08 14:59:45.849 I/yan ( 4613): TestButton-onTouchEvent-ACTION_DOWN...
Line 41: 01-08 14:59:45.939 I/yan ( 4613): MainActivity-dispatchTouchEvent-ACTION_UP...
Line 43: 01-08 14:59:45.941 I/yan ( 4613): TestButton-dispatchTouchEvent-ACTION_UP...
Line 45: 01-08 14:59:45.944 I/yan ( 4613): testBtn-onTouch-ACTION_UP...
Line 47: 01-08 14:59:45.946 I/yan ( 4613): TestButton-onTouchEvent-ACTION_UP...
Line 49: 01-08 14:59:45.974 I/yan ( 4613): testBtn---onClick...

事件先由Activity的dispatchTouchEvent进行分发，然后TestButton的dispatchTouchEvent进行分发，接着执行onTouch监听，然后执行onTouchEvent。第二次UP动作的时候，在onTouchEvent里又执行了onClick监听。
如果我们想这个TestButton只能执行onTouch监听不能执行onClick监听，方法有很多。在onTouch监听里默认返回false改为true，如下:

testBtn.setOnTouchListener(new View.OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "testBtn-onTouch-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "testBtn-onTouch-ACTION_UP...");
break;
default:break;

}
return true;
}
});

事件流程为:
Line 75: 01-08 15:05:51.627 I/yan ( 5262): MainActivity-dispatchTouchEvent-ACTION_DOWN...
Line 77: 01-08 15:05:51.628 I/yan ( 5262): TestButton-dispatchTouchEvent-ACTION_DOWN...
Line 79: 01-08 15:05:51.629 I/yan ( 5262): testBtn-onTouch-ACTION_DOWN...
Line 81: 01-08 15:05:51.689 I/yan ( 5262): MainActivity-dispatchTouchEvent-ACTION_UP...
Line 83: 01-08 15:05:51.691 I/yan ( 5262): TestButton-dispatchTouchEvent-ACTION_UP...
Line 85: 01-08 15:05:51.695 I/yan ( 5262): testBtn-onTouch-ACTION_UP...

可以看到压根就没执行onTouchEvent。因为onTouch返回了true，已提前将这个事件消费了，就不往下传了，dispatch流程提前终止。

3.ViewGroup的dispatchTouchEvent、onInterceptTouchEvent、onTouchEvent
再来看ViewGroup，在复写ViewGroup时可以发现它的onTouchEvent在在View里的，表示这两个方法是一样的。但dispatchTouchEvent是在ViewGroup里的，表示和View的dispatchTouchEvent不一样，多了一个onInterceptTouchEvent函数，表示拦截的意思。链接打个很形象的比喻，这玩意就像个秘书、谋士。为啥View没有呢，因为它级别不够，一个Button里面是不可能有子View的。但LinearLayout(继承ViewGroup)就有孩子(子布局)，这个onInterceptTouchEvent就会判断事件要不要通知它的孩子呢。它的源码如下：

public boolean dispatchTouchEvent(MotionEvent ev) {
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onTouchEvent(ev, 1);
}

boolean handled = false;
if (onFilterTouchEventForSecurity(ev)) {
final int action = ev.getAction();
final int actionMasked = action & MotionEvent.ACTION_MASK;

// Handle an initial down.
if (actionMasked == MotionEvent.ACTION_DOWN) {
// Throw away all previous state when starting a new touch gesture.
// The framework may have dropped the up or cancel event for the previous gesture
// due to an app switch, ANR, or some other state change.
cancelAndClearTouchTargets(ev);
resetTouchState();
}

// Check for interception.
final boolean intercepted;
if (actionMasked == MotionEvent.ACTION_DOWN
|| mFirstTouchTarget != null) {
fi
1075f
nal boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;
if (!disallowIntercept) {
<strong><span style="color:#ff0000;">intercepted = onInterceptTouchEvent(ev);</span></strong>
ev.setAction(action); // restore action in case it was changed
} else {
intercepted = false;
}
} else {
// There are no touch targets and this action is not an initial down
// so this view group continues to intercept touches.
intercepted = true;
}

// Check for cancelation.
final boolean canceled = resetCancelNextUpFlag(this)
|| actionMasked == MotionEvent.ACTION_CANCEL;

// Update list of touch targets for pointer down, if needed.
final boolean split = (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) != 0;
TouchTarget newTouchTarget = null;
boolean alreadyDispatchedToNewTouchTarget = false;
<strong><span style="color:#ff0000;">if (!canceled && !intercepted)</span></strong> {
if (actionMasked == MotionEvent.ACTION_DOWN
|| (split && actionMasked == MotionEvent.ACTION_POINTER_DOWN)
|| actionMasked == MotionEvent.ACTION_HOVER_MOVE) {
final int actionIndex = ev.getActionIndex(); // always 0 for down
final int idBitsToAssign = split ? 1 << ev.getPointerId(actionIndex)
: TouchTarget.ALL_POINTER_IDS;

// Clean up earlier touch targets for this pointer id in case they
// have become out of sync.
removePointersFromTouchTargets(idBitsToAssign);

final int childrenCount = mChildrenCount;
if (childrenCount != 0) {
// Find a child that can receive the event.
// Scan children from front to back.
final View[] children = mChildren;
final float x = ev.getX(actionIndex);
final float y = ev.getY(actionIndex);

final boolean customOrder = isChildrenDrawingOrderEnabled();
for (int i = childrenCount - 1; i >= 0; i--) {
final int childIndex = customOrder ?
getChildDrawingOrder(childrenCount, i) : i;
final View child = children[childIndex];
if (!canViewReceivePointerEvents(child)
|| !isTransformedTouchPointInView(x, y, child, null)) {
continue;
}

newTouchTarget = getTouchTarget(child);
if (newTouchTarget != null) {
// Child is already receiving touch within its bounds.
// Give it the new pointer in addition to the ones it is handling.
newTouchTarget.pointerIdBits |= idBitsToAssign;
break;
}

resetCancelNextUpFlag(child);
if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) {
// Child wants to receive touch within its bounds.
mLastTouchDownTime = ev.getDownTime();
mLastTouchDownIndex = childIndex;
mLastTouchDownX = ev.getX();
mLastTouchDownY = ev.getY();
newTouchTarget = addTouchTarget(child, idBitsToAssign);
alreadyDispatchedToNewTouchTarget = true;
break;
}
}
}

if (newTouchTarget == null && mFirstTouchTarget != null) {
// Did not find a child to receive the event.
// Assign the pointer to the least recently added target.
newTouchTarget = mFirstTouchTarget;
while (newTouchTarget.next != null) {
newTouchTarget = newTouchTarget.next;
}
newTouchTarget.pointerIdBits |= idBitsToAssign;
}
}
}

// Dispatch to touch targets.
if (mFirstTouchTarget == null) {
// No touch targets so treat this as an ordinary view.
handled = dispatchTransformedTouchEvent(ev, canceled, null,
TouchTarget.ALL_POINTER_IDS);
} else {
// Dispatch to touch targets, excluding the new touch target if we already
// dispatched to it.  Cancel touch targets if necessary.
TouchTarget predecessor = null;
TouchTarget target = mFirstTouchTarget;
while (target != null) {
final TouchTarget next = target.next;
if (alreadyDispatchedToNewTouchTarget && target == newTouchTarget) {
handled = true;
} else {
final boolean cancelChild = resetCancelNextUpFlag(target.child)
|| intercepted;
if (dispatchTransformedTouchEvent(ev, cancelChild,
target.child, target.pointerIdBits)) {
handled = true;
}
if (cancelChild) {
if (predecessor == null) {
mFirstTouchTarget = next;
} else {
predecessor.next = next;
}
target.recycle();
target = next;
continue;
}
}
predecessor = target;
target = next;
}
}

// Update list of touch targets for pointer up or cancel, if needed.
if (canceled
|| actionMasked == MotionEvent.ACTION_UP
|| actionMasked == MotionEvent.ACTION_HOVER_MOVE) {
resetTouchState();
} else if (split && actionMasked == MotionEvent.ACTION_POINTER_UP) {
final int actionIndex = ev.getActionIndex();
final int idBitsToRemove = 1 << ev.getPointerId(actionIndex);
removePointersFromTouchTargets(idBitsToRemove);
}
}

if (!handled && mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onUnhandledEvent(ev, 1);
}
return handled;
}

可以看到标红的有两句(intercepted = onInterceptTouchEvent(ev); if (!canceled && !intercepted) )，它会先调用 intercepted = onInterceptTouchEvent(ev);然后通过if判断。

public boolean onInterceptTouchEvent(MotionEvent ev) {
return false;
}

它就一句话，默认false。也就是说这个谋士默认的意见是，永远不拦截！！！！只要有孩子，就交给孩子们处理吧。下面给出实例说明，新建TestLinearLayout继承自Linearlayout。

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

public class TestLinearLayout extends LinearLayout{
private final static String tag = "yan";
public TestLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
switch(ev.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "TestLinearLayout-dispatchTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "TestLinearLayout-dispatchTouchEvent-ACTION_UP...");
break;
default:break;
}
return super.dispatchTouchEvent(ev);
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
switch(ev.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "TestLinearLayout-onInterceptTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "TestLinearLayout-onInterceptTouchEvent-ACTION_UP...");
break;
default:break;
}
return super.onInterceptTouchEvent(ev);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "TestLinearLayout-onTouchEvent-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "TestLinearLayout-onTouchEvent-ACTION_UP...");
break;
default:break;
}
return super.onTouchEvent(event);
}

}

布局文件改成:

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />

<org.yanzi.ui.TestLinearLayout
android:id="@+id/linearlayout_test"
android:layout_width="200dip"
android:layout_height="200dip" >

<org.yanzi.ui.TestButton
android:id="@+id/btn_test"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="测试按钮" />
</org.yanzi.ui.TestLinearLayout>

</RelativeLayout>

在Activity里给这个自定义LinearLayout也注册上onClick监听、onTouch监听。

testLinelayout = (TestLinearLayout)findViewById(R.id.linearlayout_test);
testLinelayout.setOnTouchListener(new View.OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i(tag, "testLinelayout-onTouch-ACTION_DOWN...");
break;
case MotionEvent.ACTION_UP:
Log.i(tag, "testLinelayout-onTouch-ACTION_UP...");
break;
default:break;

}
return false;
}
});

testLinelayout.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.i(tag, "testLinelayout---onClick...");
}
});

不复写事件传递里的任何方法，流程如下:

Line 57: 01-08 15:29:42.167 I/yan ( 5826): MainActivity-dispatchTouchEvent-ACTION_DOWN...
Line 59: 01-08 15:29:42.169 I/yan ( 5826): TestLinearLayout-dispatchTouchEvent-ACTION_DOWN...
Line 61: 01-08 15:29:42.169 I/yan ( 5826): TestLinearLayout-onInterceptTouchEvent-ACTION_DOWN...
Line 63: 01-08 15:29:42.169 I/yan ( 5826): TestButton-dispatchTouchEvent-ACTION_DOWN...
Line 65: 01-08 15:29:42.170 I/yan ( 5826): testBtn-onTouch-ACTION_DOWN...
Line 67: 01-08 15:29:42.170 I/yan ( 5826): TestButton-onTouchEvent-ACTION_DOWN...
---------------------------------------------------------------------------------------------------------------------------
Line 69: 01-08 15:29:42.279 I/yan ( 5826): MainActivity-dispatchTouchEvent-ACTION_UP...
Line 71: 01-08 15:29:42.280 I/yan ( 5826): TestLinearLayout-dispatchTouchEvent-ACTION_UP...
Line 73: 01-08 15:29:42.283 I/yan ( 5826): TestLinearLayout-onInterceptTouchEvent-ACTION_UP...
Line 75: 01-08 15:29:42.287 I/yan ( 5826): TestButton-dispatchTouchEvent-ACTION_UP...
Line 81: 01-08 15:29:42.298 I/yan ( 5826): testBtn-onTouch-ACTION_UP...
Line 83: 01-08 15:29:42.301 I/yan ( 5826): TestButton-onTouchEvent-ACTION_UP...
Line 85: 01-08 15:29:42.313 I/yan ( 5826): testBtn---onClick...

由Activity的dispatchTouchEvent----Linearlayout的dispatchTouchEvent------------问问它的谋士要不要让孩子知道onInterceptTouchEvent---------孩子的dispatchTouchEvent-----孩子的onTouch监听------孩子的onTouchEvent----孩子的onClick监听。为了更清晰这个流程，下面作如下改动：
1、如果事件传给了孩子们，但孩子没有onTouch和onClick监听怎么办？即将button的onclick和onTouch都注释掉:
流程如下:
Line 131: 01-08 15:36:16.574 I/yan ( 6124): TestLinearLayout-dispatchTouchEvent-ACTION_DOWN...
Line 133: 01-08 15:36:16.574 I/yan ( 6124): TestLinearLayout-onInterceptTouchEvent-ACTION_DOWN...
Line 135: 01-08 15:36:16.574 I/yan ( 6124): TestButton-dispatchTouchEvent-ACTION_DOWN...
Line 137: 01-08 15:36:16.575 I/yan ( 6124): TestButton-onTouchEvent-ACTION_DOWN...
Line 143: 01-08 15:36:16.746 I/yan ( 6124): MainActivity-dispatchTouchEvent-ACTION_UP...
Line 145: 01-08 15:36:16.747 I/yan ( 6124): TestLinearLayout-dispatchTouchEvent-ACTION_UP...
Line 147: 01-08 15:36:16.747 I/yan ( 6124): TestLinearLayout-onInterceptTouchEvent-ACTION_UP...
Line 149: 01-08 15:36:16.748 I/yan ( 6124): TestButton-dispatchTouchEvent-ACTION_UP...
Line 151: 01-08 15:36:16.748 I/yan ( 6124): TestButton-onTouchEvent-ACTION_UP...

因为事件给了孩子们，它没监听也关系不到父亲了，父亲的onClick和onTouch都没执行。
2,如果将TestLinearlayout的onInterceptTouchEvent 改成return true，即不让孩子们知道。
Line 57: 01-08 15:40:06.832 I/yan ( 6640): MainActivity-dispatchTouchEvent-ACTION_DOWN...
Line 59: 01-08 15:40:06.835 I/yan ( 6640): TestLinearLayout-dispatchTouchEvent-ACTION_DOWN...
Line 61: 01-08 15:40:06.836 I/yan ( 6640): TestLinearLayout-onInterceptTouchEvent-ACTION_DOWN...
Line 63: 01-08 15:40:06.836 I/yan ( 6640): testLinelayout-onTouch-ACTION_DOWN...
Line 65: 01-08 15:40:06.836 I/yan ( 6640): TestLinearLayout-onTouchEvent-ACTION_DOWN...
Line 67: 01-08 15:40:07.016 I/yan ( 6640): MainActivity-dispatchTouchEvent-ACTION_UP...
Line 69: 01-08 15:40:07.017 I/yan ( 6640): TestLinearLayout-dispatchTouchEvent-ACTION_UP...
Line 73: 01-08 15:40:07.025 I/yan ( 6640): testLinelayout-onTouch-ACTION_UP...
Line 75: 01-08 15:40:07.026 I/yan ( 6640): TestLinearLayout-onTouchEvent-ACTION_UP...
Line 77: 01-08 15:40:07.052 I/yan ( 6640): testLinelayout---onClick...
果然事件就此打住，孩子们压根不知道，父亲执行了onClick和onTouch监听。可见父亲还是伟大的啊，只要谋士不拦截事件，那么事件就给孩子。
最后的结论:
1、如果是自定义复合控件，如图片+文字，我再Activity里给你注册了onClick监听，期望点击它执行。那么最简单的方法就是将图片+文字的父布局，也即让其容器ViewGroup的秘书将事件拦下，这样父亲就可以执行onClick了。这时候的父亲就像一个独立的孩子一样了(View)，无官一身轻，再也不用管它的孩子了,可以正常onClick onTouch.
2、如果希望一个View只onTouch而不onClick，在onTouch里return true就ok了。
3、dispatch是为了onTouch监听，onTouchEvent是为了onClick监听。
4、自定义布局时，一般情况下：
@Override
public boolean onTouchEvent(MotionEvent event) {return super.onTouchEvent(event);}

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

我们可以复写，但是最后的super.***是万万不能少滴。如果少了，表示连dispatch*** onTouchEvent压根就不调用了，事件就此打住。

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标签： View事件传递

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