ListView 的Item更改背景图片

三个文件：

listview:

<!-- 列表开始 -->

<ListView

android:id="@+id/lv"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:drawSelectorOnTop="false"

android:layout_below="@id/currentitem"

android:layout_above="@id/GridView_toolbar"

android:layout_marginTop="5dp"

android:layout_marginBottom="-3dp"

android:dividerHeight="10dp"

android:divider="@null"

android:fastScrollEnabled="true"

android:cacheColorHint="#00000000"

android:focusable="true"

/>

<!-- 列表结束 -->

list_item:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:background="@drawable/list_selector" >

....</RelativeLayout>

list_selector:

<?xml version="1.0" encoding="utf-8"?>

<selector xmlns:android="http://schemas.android.com/apk/res/android">

<item android:drawable="@drawable/course_list_background_pressed"

android:state_pressed="true"></item>

<item android:drawable="@drawable/course_list_background"

android:state_pressed="false"></item>

</selector>