android shape stroke只绘制一边或者某几边

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

     <item
         android:right="-2dp"
         android:top="-2dp">
         <shape>
             <solid android:color="@color/white" />
             <stroke
                 android:width="1px"
                 android:color="@color/split_line" />
         </shape>
     </item>
 </layer-list>

-2dp表示不绘制这一边