[代码]按钮selector

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
 <item android:state_pressed="true" android:drawable="@drawable/camera3" />
 <item android:state_pressed="false" android:state_focused="false"
  android:drawable="@drawable/camera1" />
 <item android:state_focused="true" android:drawable="@drawable/camera2" />
 <item android:state_focused="false" android:drawable="@drawable/camera1" />
</selector>

 定义按钮的多个状态,做出动态效果