drawable폴더에서 xml을 만들어줍니다.

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#FFFFFF"/>
    <stroke android:width="3dip" android:color="#B1BCBE" />
    <corners android:radius="10dip"/>
    <padding android:left="0dip" android:top="0dip" android:right="0dip" android:bottom="0dip" />
</shape>

rounded.xml

둥글게하고싶은 레이아웃에 속성을 적용시킵니다.

android:background="@drawable/rounded"