<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <!-- 填充颜色 -->
    <solid android:color="@color/white"></solid>
    <!-- 线的宽度，颜色灰色 -->
    <stroke
        android:width="3dp"
        android:color="@color/md_blue_500" />
</shape>  
