点击Button字体变色，图片变化，背景变化

<?xml version="1.0" encoding="utf-8"?>  
<resources>  
    <drawable name="red">#f00</drawable>  
    <drawable name="green">#0f0</drawable>  
    <drawable name="gray">#ccc</drawable>  
</resources> 

1 <?xml version="1.0" encoding="utf-8"?>  
2 <selector xmlns:android="http://schemas.android.com/apk/res/android">  
3     <item android:state_window_focused="false" android:state_enabled="true"  
4         android:drawable="@drawable/btn_test_normal" />  
5     <item android:state_enabled="false" android:drawable="@drawable/btn_test_normal" />  
6     <item android:state_pressed="true" android:drawable="@drawable/btn_test_press" />  
7     <item android:state_focused="true"
8 android:drawable="@drawable/btn_test_normal" />  
9 </selector> 

1     <?xml version="1.0" encoding="utf-8"?>  
2     <selector xmlns:android="http://schemas.android.com/apk/res/android">  
3         <item android:state_focused="false" android:state_enabled="true" android:state_pressed="false"  
4             android:color="@drawable/red" />  
5         <item android:state_enabled="false" android:color="@drawable/gray" />  
6         <item android:state_pressed="true" android:color="@drawable/green" />  
7         <item android:state_focused="true"  android:color="@drawable/red" />  
8     </selector>  

1 <Button  
2         android:layout_width="wrap_content"  
3         android:layout_height="wrap_content"  
4         android:text="按下文字会变效果"  
5         android:textColor="@drawable/btn_color"  
6         android:background="@drawable/btn_bg"  
7         />