SubwayTooter-Android-App/app/src/main/res/drawable/btn_bg_transparent.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_pressed="true">
        <shape android:shape="rectangle">
            <solid android:color="#FF808080" />
        </shape>
    </item>

    <item android:state_selected="true">
        <shape android:shape="rectangle">
            <solid android:color="#00000080" />
        </shape>
    </item>

    <item android:state_focused="true">
        <shape android:shape="rectangle">
            <solid android:color="#00000080" />
        </shape>
    </item>
    <item>
        <shape android:shape="rectangle">
            <solid android:color="#00000000" />
        </shape>
    </item>
</selector>