but_background.xml

<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:color="#f88e8e8e"
    tools:targetApi="lollipop">
    <item android:id="@+id/mask">
        <shape android:shape="rectangle">
            <solid android:color="#ecebeb"/>
            <corners android:radius="20dp"/>
        </shape>
    </item>
</ripple>