android - 更改 ExpandableListView 中的可扩展指示器

Question

尝试创建 ExpandableListView。组的初始 View 显示良好。但是，当我单击列表项时，我的箭头不会改变。请参阅下面的图片。

如何改变箭头的方向？

布局 XML:

  <ExpandableListView
        android:id="@+id/expandable_list"
        android:layout_width="fill_parent"
        android:layout_height="match_parent"            
        android:divider="@null"
        android:background="#ffffff"
        android:groupIndicator="@drawable/settings_selector"
        android:transcriptMode="alwaysScroll" />

settings_selector.xml:

 <?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android" >

<selector xmlns:android="http://schemas.android.com/apk/res/android" >
    <item
        android:drawable="@drawable/arrow_down"
        android:state_empty="true"/>
    <item
        android:drawable="@drawable/arrow_right"
        android:state_expanded="true"/>
</selector>

</animation-list>

Answer 1

可扩展的 ListView

 <ExpandableListView
    android:id="@+id/expandable_list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:groupIndicator="@drawable/group_indicator"
    android:transcriptMode="alwaysScroll" />

setindicator 这里我正在使用这样的 setindicator 代码，这很好用

 DisplayMetrics metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    int width = metrics.widthPixels; 

 mExpandableList = (ExpandableListView)findViewById(R.id.expandable_list);
 mExpandableList.setIndicatorBounds(width - GetPixelFromDips(50), width - GetPixelFromDips(10));  

   public int GetPixelFromDips(float pixels) {
    // Get the screen's density scale 
    final float scale = getResources().getDisplayMetrics().density;
    // Convert the dps to pixels, based on density scale
    return (int) (pixels * scale + 0.5f);
}

res/drawable/group_indicator

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

     <selector xmlns:android="http://schemas.android.com/apk/res/android">            
           <item android:drawable="@drawable/arrow_right" android:state_empty="true">  </item>            
           <item android:drawable="@drawable/arrow_down" android:state_expanded="true"></item>                
           <item android:drawable="@drawable/arrow_right"></item>
     </selector>