You can use something like this :
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:state_pressed="true" android:drawable="@color/holo_blue_overlay" />
<item android:state_focused="true" android:drawable="@color/holo_blue_overlay" />
<item android:state_selected="true" android:drawable="@color/holo_blue_overlay" />
<item android:drawable="@android:color/transparent" />
</selector>