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

    <!-- 颜色填充方式绘画按钮 -->
    <!--<solid android:color="?attr/colorPrimaryDark" />-->

    <stroke
        android:width="2dp"
        android:color="?attr/colorPrimary" />

    <corners android:radius="15dp" />

    <!-- 颜色线性渐变方式绘画按钮 -->
    <gradient
        android:angle="270"
        android:startColor="?attr/colorAccent"
        android:centerColor="?attr/colorPrimary"
        android:endColor="?attr/colorPrimaryDark"/> 

    <padding
        android:left="5dp"
        android:top="5dp" 
        android:right="5dp"
        android:bottom="5dp" />

</shape>
