android中select和pressed混用

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android">    <item android:drawable="@drawable/menubar_toggle_p" android:state_pressed="true"/>    <item android:drawable="@drawable/menubar_toggle_p" android:state_selected="true"/>    <item android:drawable="@drawable/menubar_toggle_d"/></selector> <item android:drawable="@drawable/menubar_toggle_d"/>写在前面会无效，草，不知道为啥