给View设置独立border

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <!-- 连框颜色值 -->
    <item>
        <shape>
            <solid android:color="#ad2a2b" />
        </shape>
    </item>
    <!-- 主体背景颜色值 -->
    <item android:bottom="1dp"> <!--设置只有底部有边框-->
        <shape>
            <solid android:color="@android:color/white" />
        </shape>
    </item>
</layer-list>