I am trying to understand how to implement the \"Ripple Effect - Touch Feedback\" for buttons and other views. I looked at the questions related to Ripple touch effect on SO
Just put ?attr/selectableItemBackground in the background of button for API 21+ , like below:
?attr/selectableItemBackground
<Button android:layout_width="match_parent" android:layout_height="70dp" android:background="?attr/selectableItemBackground" android:text="Button" />