GMAndroid/app/src/main/res/drawable/arrowbuttonselector.xml

<!-- Selector for the arrow buttons -->

<selector
    xmlns:android="http://schemas.android.com/apk/res/android">
	<item
	    android:state_focused="true"
	    android:drawable="@drawable/arrowbutton"/>
	<item
	    android:state_pressed="true"
	    android:drawable="@drawable/arrowbuttonpressed" />
	<item
	    android:drawable="@drawable/arrowbutton" />
</selector>