Create a new xml file inside drawable folder and save it as rectangle.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<solid android:color="@android:color/transparent"/>
<corners android:radius="12px"/>
<stroke android:width="2dip" android:color="#000000"/>
</shape>
