HEGII.ss.mes.pda/res/drawable/selector_checkbox1.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_enabled="true" android:state_checked="false" android:drawable="@drawable/checkbox1_unselect" />
    <item android:state_enabled="true" android:state_checked="true" android:drawable="@drawable/checkbox1_selected" />
    <item android:drawable="@drawable/checkbox1_unselect" />
</selector>