sheishuoAPP/uikit/res/drawable/nim_message_view_bottom.xml

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

    <item>
        <shape android:shape="rectangle" >
            <solid android:color="#e3e5e7" />
        </shape>
    </item>
    <item
        android:bottom="2px"
        android:top="2px">
        <shape android:shape="rectangle" >
            <solid android:color="@color/white" />
        </shape>
    </item>

</layer-list>