SubwayTooter-Android-App/app/src/main/res/drawable-v21/btn_bg_ddd.xml

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