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

<?xml version="1.0" encoding="utf-8"?>
<ripple
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="?attr/colorRippleEffect"
    >
    <item
        android:id="@android:id/mask"
        android:drawable="@android:color/white"
        />
</ripple>