Create rounded_btn.xml file in Drawable folder...
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="@color/#FFFFFF"/>
<stroke android:width="1dp"
android:color="@color/#000000"
/>
<padding android:left="1dp"
android:top="1dp"
android:right="1dp"
android:bottom="1dp"
/>
<corners android:bottomRightRadius="5dip" android:bottomLeftRadius="5dip"
android:topLeftRadius="5dip" android:topRightRadius="5dip"/>
</shape>
and use this.xml file as a button background
<Button
android:id="@+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/rounded_btn"
android:text="Test" />