Here is the top answer to create border in Relative Layout in Android
Create a file called border.xml in your drawable folder:
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<corners android:radius="20dp"/>
<padding android:left="10dp" android:right="10dp" android:top="10dp" android:bottom="10dp"/>
<stroke android:width="1dp" android:color="#CCCCCC"/>
</shape>
RelativeLayout rectangle=new RelativeLayout(getContext());
rectangle.setBackgroundColor(Color.BLUE);
rectangle.setBackgroundResource(R.drawable.border);
Here is answer to add border in Android LinearLayout ?
<LinearLayout android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/customborder">