selector选择器

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/mei_bg_checked"
        android:state_checked="true"></item>
    <item android:drawable="@drawable/mei_bg"></item>
</selector>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid android:color="#Ff0000" ></solid>
    <size android:width="30dp"
        android:height="30dp"></size>
</shape>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid android:color="#F38722"></solid>
    <size android:width="30dp"
        android:height="30dp"></size>
</shape>