android - Change expandable indicator in ExpandableListView

Question

Trying to create an ExpandableListView. The initial view with the groups shows up fine. However, when I click the list item, my arrow does not change. See the images below.

How can I change the arrow's direction?

The layout 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

expandable 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 here iam useing setindicator code like this this working nice

 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>