首先android的selector是在drawable/xxx.xml中配置的，相关图片放在同目录下。
先看一下listview中的状态： 把下面的XML文件保存成你自己命名的.xml文件（比如list_item_bg.xml），在系统使用时根据ListView中的列表项的状态来使用相应的背景图片。 <? xml version ="1.0" encoding ="utf-8" ?>
< selector xmlns:android ="http://schemas.android.com/apk/res/android" >

     < item android:drawable ="@drawable/pic1" />


     < item android:state_window_focused ="false"
                 android:drawable ="@drawable/pic1" />


     < item android:state_focused ="true"
                 android:state_pressed ="true"
                android:drawable= "@drawable/pic2" />


     < item android:state_focused ="false"
                 android:state_pressed ="true"
                 android:drawable ="@drawable/pic3" />


     < item android:state_selected ="true"
                 android:drawable ="@drawable/pic4" />


     < item android:state_focused ="true"
                 android:drawable ="@drawable/pic5" />
selector >
使用xml文件： 1.方法一：在listview中配置 android:listSelector="@drawable/xxx" 或者在listview的item中添加属性android：background="@drawable/xxx"
2.方法二：是   Drawable drawable = getResources().getDrawable(R.drawable.xxx);      ListView.setSelector(drawable); 但是这样会出现列表有时候为黑的情况，需要加上：a ndroid:cacheColorHint="@android:color/transparent"使其透明。
相关属性： android:state_selected是选中 android:state_focused是获得焦点 android:state_pressed是点击 android:state_enabled是设置是否响应事件,指所有事件   根据这些状态同样可以设置button的selector效果。也可以设置selector改变button中的文字状态。
以下是配置button中的文字效果： drawable/button_font.xml <? xml version ="1.0" encoding ="utf-8" ?>
< selector xmlns:android ="http://schemas.android.com/apk/res/android" >
         < item android:state_selected ="true" android:color ="#FFF" />
         < item android:state_focused ="true" android:color ="#FFF" />
         < item android:state_pressed ="true" android:color ="#FFF" />
         < item android:color ="#000" />
selector >
Button还可以实现更复杂的效果，例如渐变 drawable/button_color.xml <? xml version ="1.0" encoding ="utf-8" ?>
< selector xmlns:android ="http://schemas.android.com/apk/res/android" >                 /
         < item android:state_pressed ="true" >//定义当button 处于pressed 状态时的形态。
                 < shape >
                         < gradient android:startColor ="#8600ff" />
                         < stroke     android:width ="2dp" android:color ="#000000" />
                         < corners android:radius ="5dp" />
                         < padding android:left ="10dp" android:top ="10dp"
                                         android:bottom ="10dp" android:right ="10dp" />
                 shape >
         item >
         < item android:state_focused ="true" >//定义当button获得 focus时的形态
                 < shape >
                         < gradient android:startColor ="#eac100" />
                         < stroke     android:width ="2dp" android:color ="#333333"     color ="#ffffff" />
                         < corners android:radius ="8dp" />
                         < padding android:left ="10dp" android:top ="10dp"
                                         android:bottom ="10dp" android:right ="10dp" />
                 shape >
         item >
selector >
    最后，需要在包含 button的xml文件里添加两项。假如是 main.xml 文件， 我们需要在