bg_sop_item.xml

<?xml version="1.0" encoding="UTF-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 边框颜色值 -->
    <item>
        <shape>
            <solid android:color="#999" />
        </shape>
    </item>

    <!--这个是按钮边框设置为四周 并且宽度为1-->
    <item
        android:top="@dimen/dp_sale_step"
        >
        <shape>
            <!--这个是背景颜色-->
            <solid android:color="@color/white" />
        </shape>
    </item>
</layer-list>