android 图片背景使用这种方式很爽

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android=" http://schemas.android.com/apk/res/android">  <item   android:state_pressed="false"   android:drawable="@drawable/button_green_three1"  />    <item   android:state_pressed="true"   android:drawable="@drawable/button_green_three_press"  />    <item   android:drawable="@drawable/button_green_three1"  /> </selector>