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addStatesFromChildren 和跑马灯

程序员文章站 2022-03-14 14:59:44
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在Android中要显示跑马灯是比较容易的,只要设置2个属性就可以了:
android:singleLine="true"
android:ellipsize="marquee"

但 是要显示跑马灯该View必需是可以取得焦点的,只有在取得焦点的情况下跑马灯才会出现.
如果是组合View的情况下就有问题了, 如下一个组合View:

<!-- <br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> --><? xml version="1.0" encoding="utf-8" ?>
< LinearLayout
  
xmlns:android ="http://schemas.android.com/apk/res/android"
  android:orientation
="vertical"
  android:gravity
="center_vertical"
  android:background
="@drawable/f_background"
  android:layout_width
="fill_parent"
  android:focusable
="true"
  android:layout_height
="50px" >
  
< TextView 
      
android:id ="@+id/info_text"
      android:focusable
="true"
      android:layout_width
="fill_parent"
      android:layout_height
="wrap_content"
      android:text
="test marquee addStatesFromChildren 和跑马灯
            
    
    博客分类: Java AndroidXMLF#addStatesFromChildren 和跑马灯
            
    
    博客分类: Java AndroidXMLF#addStatesFromChildren 和跑马灯
            
    
    博客分类: Java AndroidXMLF#addStatesFromChildren 和跑马灯
            
    
    博客分类: Java AndroidXMLF#addStatesFromChildren 和跑马灯
            
    
    博客分类: Java AndroidXMLF#addStatesFromChildren 和跑马灯
            
    
    博客分类: Java AndroidXMLF# .. "
      android:textColor
="@color/black"
      android:singleLine
="true"
      android:ellipsize
="marquee"
      android:marqueeRepeatLimit
="3"
      android:textSize
="18sp"
  
/>
  
< TextView 
      
android:id ="@+id/date_text"
      android:layout_width
="fill_parent"
      android:layout_height
="wrap_content"
      android:layout_gravity
="bottom"
      android:textColor
="@color/gray"
      android:text
="2010/05/28"
      android:textSize
="12sp"
  
/>
</ LinearLayout >


上面示例中2个TextView组合为一个View,由于设置了LinearLayout为focusable而TextView就没法取得焦点了,这样 这个TextView的跑马灯效果就显示不出来,就算你也设置TextView的 android:focusable= "true" 也是 没用的. 这个时候就要使用addStatesFromChildren 这个属性了,在LinearLayout中设置这个属性,然后设置TextView的focusable= "true" 就可以了.关于 addStatesFromChildren的说明:

Sets whether this ViewGroup's drawable states also include its children's drawable states.

可以正常显示的代码:

<!-- <br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> --><? xml version="1.0" encoding="utf-8" ?>
< LinearLayout
  
xmlns:android ="http://schemas.android.com/apk/res/android"
  android:orientation
="vertical"
  android:gravity
="center_vertical"
  android:background
="@drawable/zixun_background"
  android:layout_width
="fill_parent"
  android:addStatesFromChildren
="true"
  android:layout_height
="50px" >
  
< TextView 
      
android:id ="@+id/info_text"
      android:focusable
="true"
      android:layout_width
="fill_parent"
      android:layout_height
="wrap_content"
      android:text
=" "
      android:textColor
="@color/black"
      android:singleLine
="true"
      android:ellipsize
="marquee"
      android:marqueeRepeatLimit
="3"
      android:textSize
="18sp"
  
/>
  
< TextView 
      
android:id ="@+id/date_text"
      android:layout_width
="fill_parent"
      android:layout_height
="wrap_content"
      android:layout_gravity
="bottom"
      android:textColor
="@color/gray"
      android:text
="2010/05/28"
      android:textSize
="12sp"
  
/>
</ LinearLayout >
相关标签: Android XML F#