如果题主只是想实现布局底部分割线的效果，那么在底部放入

<View
    android:layout_width="match_parent"
    android:layout_height="0.5dip"
    android:background="#9d9d9d" />

即可

如果题主一定要实现只绘制出一个边框的矩形，那么可以继承View自定义

好说，自定义view、attr.xml，在onDraw画出来，方向、颜色、宽窄，都可以自己控制。百度一下，不难。

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android&quot; >

<item>
    <shape android:shape="rectangle" >
        <solid android:color="#bbbbbb" />

        <corners
            android:bottomLeftRadius="0px"
            android:bottomRightRadius="0px"
            android:topLeftRadius="0px"
            android:topRightRadius="0px" />
    </shape>
</item>
<item android:top="1dp">
    <shape android:shape="rectangle" >
        <solid android:color="#eeeeee" />

        <corners
            android:bottomLeftRadius="0px"
            android:bottomRightRadius="0px"
            android:topLeftRadius="0px"
            android:topRightRadius="0px" />
    </shape>
</item>

</layer-list>

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <stroke android:color="#b3b3b3" android:width="1dp"/>
            <padding android:bottom="1dp"/>
        </shape>
    </item>
    <item>
        <shape android:shape="rectangle">
            <solid android:color="#ffffff"/>
        </shape>
    </item>
</layer-list>

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item
    android:top="-2dp"
    android:left="-2dp"
    android:right="-2dp">
    <shape>
        <stroke
            android:width="1dp"
            android:color="@color/gray" />
    </shape>
</item>

</layer-list>
background就可以了