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---------------------http://www.cnblogs.com/jisheng/archive/2011/12/16/2290348.html

2014-04-21 16:24 351 查看
http://www.cnblogs.com/jisheng/archive/2011/12/16/2290348.html

http://www.blogjava.net/TiGERTiAN/archive/2011/02/22/344869.html

由于ViewGroup会包含若干childView,因此需要能够统一监控各种touch事件的机会,因此纯粹的不能包含子view的控件是没有这个方法的,如LinearLayout就有,TextView就没有。

下面用一个简单的实验说明上述复杂的规则。视图自底向上共3层,其中LayoutView1和LayoutView2就是LinearLayout, MyTextView就是TextView:

对应的xml布局文件如下:

<?xml version="1.0" encoding="utf-8"?>

<com.touchstudy.LayoutView1 xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent" >

<com.touchstudy.LayoutView2

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center">

<com.touchstudy.MyTextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/tv"

android:text="AB"

android:textSize="40sp"

android:textStyle="bold"

android:background="#FFFFFF"

android:textColor="#0000FF"/>

</com.touchstudy.LayoutView2>

</com.touchstudy.LayoutView1>

下面看具体情况:

1. onInterceptTouchEvent()处理down事件均返回false,onTouchEvent()处理事件均返回true

------------------------------------------------------------------------------------------------------------------------------

04-11 03:58:42.620: DEBUG/LayoutView1(614): onInterceptTouchEvent action:ACTION_DOWN

04-11 03:58:42.620: DEBUG/LayoutView2(614): onInterceptTouchEvent action:ACTION_DOWN

04-11 03:58:42.620: DEBUG/MyTextView(614): onTouchEvent action:ACTION_DOWN

04-11 03:58:42.800: DEBUG/LayoutView1(614): onInterceptTouchEvent action:ACTION_MOVE

04-11 03:58:42.800: DEBUG/LayoutView2(614): onInterceptTouchEvent action:ACTION_MOVE

04-11 03:58:42.800: DEBUG/MyTextView(614): onTouchEvent action:ACTION_MOVE

…… //省略过多的ACTION_MOVE

04-11 03:58:43.130: DEBUG/LayoutView1(614): onInterceptTouchEvent action:ACTION_UP

04-11 03:58:43.130: DEBUG/LayoutView2(614): onInterceptTouchEvent action:ACTION_UP

04-11 03:58:43.150: DEBUG/MyTextView(614): onTouchEvent action:ACTION_UP

------------------------------------------------------------------------------------------------------------------------------

这是最常见的情况,onInterceptTouchEvent并没有做任何改变事件传递时序的操作,效果上和没有覆写该方法是一样的。可以看到,各种事件的传递本身是自底向上的,次序是:LayoutView1->LayoutView2->MyTextView。注意,在onInterceptTouchEvent均返回false时,LayoutView1和LayoutView2的onTouchEvent并不会收到事件,而是最终传递给了MyTextView。

2.LayoutView1的onInterceptTouchEvent()处理down事件返回true,

MyTextView的onTouchEvent()处理事件返回true

------------------------------------------------------------------------------------------------------------------------------

04-11 03:09:27.589: DEBUG/LayoutView1(446): onInterceptTouchEvent action:ACTION_DOWN

04-11 03:09:27.589: DEBUG/LayoutView1(446): onTouchEvent action:ACTION_DOWN

04-11 03:09:27.629: DEBUG/LayoutView1(446): onTouchEvent action:ACTION_MOVE

04-11 03:09:27.689: DEBUG/LayoutView1(446): onTouchEvent action:ACTION_MOVE

…… //省略过多的ACTION_MOVE

04-11 03:09:27.959: DEBUG/LayoutView1(446): onTouchEvent action:ACTION_UP

------------------------------------------------------------------------------------------------------------------------------

从Log可以看到,由于LayoutView1在拦截第一次down事件时return true,所以后续的事件(包括第一次的down)将由LayoutView1本身处理,事件不再传递下去。

3.LayoutView1,LayoutView2的onInterceptTouchEvent()处理down事件返回false,

MyTextView的onTouchEvent()处理事件返回false

LayoutView2的onTouchEvent()处理事件返回true

----------------------------------------------------------------------------------------------------------------------------

04-11 09:50:21.147: DEBUG/LayoutView1(301): onInterceptTouchEvent action:ACTION_DOWN

04-11 09:50:21.147: DEBUG/LayoutView2(301): onInterceptTouchEvent action:ACTION_DOWN

04-11 09:50:21.147: DEBUG/MyTextView(301): onTouchEvent action:ACTION_DOWN

04-11 09:50:21.147: DEBUG/LayoutView2(301): onTouchEvent action:ACTION_DOWN

04-11 09:50:21.176: DEBUG/LayoutView1(301): onInterceptTouchEvent action:ACTION_MOVE

04-11 09:50:21.176: DEBUG/LayoutView2(301): onTouchEvent action:ACTION_MOVE

04-11 09:50:21.206: DEBUG/LayoutView1(301): onInterceptTouchEvent action:ACTION_MOVE

04-11 09:50:21.217: DEBUG/LayoutView2(301): onTouchEvent action:ACTION_MOVE

…… //省略过多的ACTION_MOVE

04-11 09:50:21.486: DEBUG/LayoutView1(301): onInterceptTouchEvent action:ACTION_UP

04-11 09:50:21.486: DEBUG/LayoutView2(301): onTouchEvent action:ACTION_UP

----------------------------------------------------------------------------------------------------------------------------

可以看到,由于MyTextView在onTouchEvent()中return false,down事件被传递给其父view,即LayoutView2的onTouchEvent()方法处理,由于在LayoutView2的onTouchEvent()中return true,所以down事件传递并没有上传到LayoutView1。注意,后续的move和up事件均被传递给LayoutView2的onTouchEvent()处理,而没有传递给MyTextView。

另一种情况,在一个ListView中

onInterceptTouchEvent 返回false

接着它的onTouchEvent就不停的返回ActionMove。
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