Android ImageView setImageLevel和level-list

<level-list xmlns:android="http://schemas.android.com/apk/res/android"> 
    <item android:maxLevel="0" android:drawable="@drawable/p0" /> 
    <item android:maxLevel="1" android:drawable="@drawable/p1" /> 
    <item android:maxLevel="2" android:drawable="@drawable/p2" /> 
    <item android:maxLevel="3" android:drawable="@drawable/p3" /> 
    <item android:maxLevel="4" android:drawable="@drawable/p3" /> 
</level-list>

ImageView image=(ImageView)findViewById(R.id.image); 
            image.setImageResource(R.drawable.q); 
            image.setImageLevel(3);