Pick random tip from the tip file each time front page is viewed.
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_focused="true" android:state_enabled="true" android:drawable="@drawable/dropdown_focused" />
<item android:state_focused="true" android:state_enabled="false" android:drawable="@drawable/dropdown_focused_disabled" />
<item android:state_focused="false" android:state_enabled="true" android:drawable="@drawable/dropdown_normal" />
<item android:state_focused="false" android:state_enabled="false" android:drawable="@drawable/dropdown_disabled" />
</selector>