<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 定义按钮按下时的图片 -->
    <item android:drawable="@drawable/detail_center_react"
        android:state_selected="true"/>
    <!-- 定义按钮默认的图片 -->
    <item android:drawable="@drawable/detail_center_react_unselected"/>
</selector>