I try to switch the background of Buttons if they are pressed. I build a Selector like the answer suggested here: Standard Android Button with a different color
Fin
put this at the end
item android:drawable="@color/red"
i mean as the third option, it will work. android checks the xml conditions from the start, the first tag doesn't have any condition, so it will always pick red, so you have put conditions first and then the default one.
here is the code I use, and it works really well.
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/button_clicked"
android:state_pressed="true" android:state_enabled="true" />
<item android:drawable="@drawable/button" android:state_enabled="true" />
</selector>
here I use two images I made using photoshop as a background
the first is button_clicked and the second is button
copy it and change use your own resources.
hope I could help :)