android selector 无效的问题

这几天做项目，用到背景选择器，无论怎么弄，都没有效果，找了很多资料都没有找到，样式是这样的

<?xml version="1.0" encoding="UTF-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
　　 <item android:drawable="@drawable/title_new_normal"/>
    <item android:drawable="@drawable/title_new_selected" android:state_focused="true"/>
    <item android:drawable="@drawable/title_new_selected" android:state_selected="true"/>
    <item android:drawable="@drawable/title_new_selected" android:state_pressed="true"/>
    <item android:drawable="@drawable/title_new_selected" android:state_enabled="false"/>
    

</selector>

后来偶然间，把默认的放在最下面，就好用啦

<?xml version="1.0" encoding="UTF-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/title_new_selected" android:state_focused="true"/>
    <item android:drawable="@drawable/title_new_selected" android:state_selected="true"/>
    <item android:drawable="@drawable/title_new_selected" android:state_pressed="true"/>
    <item android:drawable="@drawable/title_new_selected" android:state_enabled="false"/>
    <item android:drawable="@drawable/title_new_normal"/>

</selector>

 希望和我一样翻过类似错误的同仁，有个帮助