How to make a round button?

Create an xml file named roundedbutton.xml in drawable folder

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
android:shape="rectangle">
    <solid android:color="#eeffffff" />
    <corners android:bottomRightRadius="8dp"
        android:bottomLeftRadius="8dp"  
        android:topRightRadius="8dp"
        android:topLeftRadius="8dp"/>
</shape>

Finally set that as background to your Button as android:background = "@drawable/roundedbutton"

If you want to make it completely rounded, alter the radius and settle for something that is ok for you.