Android material design buttons – Pre lollipop-open source projects angular/material
 Gabriel
This requires Android 5.0
Raised Button
Inherit your button style from Widget.Material.Button, and the standard elevation and raising action will automatically be applied.
    @drawable/raised_button_background
Then you need to create a raised_button_background.xml file with your button’s background color inside a ripple tag:
    
Flat Button
Edit: Instead of my previous advice for flat buttons, you should instead use follow the advice given by Stephen Kaiser below: