Android button different state background

button_drawable_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:state_pressed="false"
        android:drawable="@drawable/title_button_back">
    </item>
    <item
        android:state_pressed="true"
        android:drawable="@drawable/title_button_back_h">
    </item>
    <item
        android:state_window_focused="false"
        android:drawable="@drawable/title_button_back">
    </item>
</selector>

gistfile1.txt

<?xml version="1.0" encoding="utf-8"?>  
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_height="wrap_content" 
    android:layout_width="fill_parent">  
    <ImageButton 
        android:id="@+id/title_IB" ; 
        android:layout_height="wrap_content" 
        android:layout_width="wrap_content" 
        android:background="#00000000" 
        android:layout_marginRight="4dp" 
        android:layout_centerVertical="true" 
        android:src="@drawable/selector"> ; 
    </ImageButton>  
</RelativeLayout>

shameless copy from http://www.oschina.net/question/54100_34076