<?xml version="1.0" encoding="UTF-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
	<!-- 指定按钮按下时的图片 -->
	<item android:state_pressed="true"
		android:drawable="@drawable/start_down"
	/>
	<!-- 指定按钮松开时的图片 -->	
	<item android:state_pressed="false"
		android:drawable="@drawable/start"
	/>
</selector>