关于listview_Android

关于listview求助
xml：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/layout"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <TextView
        android:id="@+id/list_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="24dp"
        android:layout_centerVertical="true" />

    <ImageView android:id="@+id/list_radioImg"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"/>
</RelativeLayout>
代码：
public class SchoolMainActivity extends ListActivity {
private int balanceIndex = 0;
SimpleAdapter adapter;
List<Map<String, Object>> list;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
adapter= new SimpleAdapter(this,getData(),R.layout.array_item,new String[]{"text","img"},new int[]{R.id.list_text,R.id.list_radioImg});
setListAdapter(adapter);
}
private List<Map<String, Object>> getData(){
list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_xsgl = new HashMap<String, Object>();
map_xsgl.put("text", "学生管理");
map_xsgl.put("img", R.drawable.on);
list.add(map_xsgl);

list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_jsgl = new HashMap<String, Object>();
map_jsgl.put("text", "教师管理");
map_jsgl.put("img", R.drawable.off);
list.add(map_jsgl);

list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_xxck = new HashMap<String, Object>();
map_xxck.put("text", "信息查看");
map_xxck.put("img", R.drawable.off);
list.add(map_xxck);

list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_bjgn = new HashMap<String, Object>();
map_bjgn.put("text", "报警功能");
map_bjgn.put("img", R.drawable.off);
list.add(map_bjgn);

return list;
}

protected void onListItemClick(ListView arg0, View arg1, int arg2, long arg3) {
Toast t = Toast.makeText(this, ""+list.get(arg2).get("text"), Toast.LENGTH_LONG);
t.show();

ChangeRadioImg(balanceIndex,false);
ChangeRadioImg(arg2,true);
balanceIndex=arg2;

list.get(arg2).get("text");
}

private void ChangeRadioImg(int selectedItem, boolean b) {
SimpleAdapter la = adapter;
HashMap<String, Object> map = (HashMap<String, Object>)la.getItem(selectedItem);
if(b)
{
map.put("img", R.drawable.on);
}
else
{
map.put("img", R.drawable.off);

}
la.notifyDataSetChanged();
}
}
结果：
如图，只显示了最后一行数据
新手求教
------解决思路----------------------


private List<Map<String, Object>> getData(){
list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_xsgl = new HashMap<String, Object>();
map_xsgl.put("text", "学生管理");
map_xsgl.put("img", R.drawable.on);
list.add(map_xsgl);

Map<String, Object> map_jsgl = new HashMap<String, Object>();
map_jsgl.put("text", "教师管理");
map_jsgl.put("img", R.drawable.off);
list.add(map_jsgl);

Map<String, Object> map_xxck = new HashMap<String, Object>();
map_xxck.put("text", "信息查看");
map_xxck.put("img", R.drawable.off);
list.add(map_xxck);

Map<String, Object> map_bjgn = new HashMap<String, Object>();
map_bjgn.put("text", "报警功能");
map_bjgn.put("img", R.drawable.off);
list.add(map_bjgn);

return list;
}

------解决思路----------------------
你这里
list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_xsgl = new HashMap<String, Object>();
map_xsgl.put("text", "学生管理");
map_xsgl.put("img", R.drawable.on);
list.add(map_xsgl);

list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_jsgl = new HashMap<String, Object>();
map_jsgl.put("text", "教师管理");
map_jsgl.put("img", R.drawable.off);
list.add(map_jsgl);

list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_xxck = new HashMap<String, Object>();
map_xxck.put("text", "信息查看");
map_xxck.put("img", R.drawable.off);
list.add(map_xxck);

list = new ArrayList<Map<String, Object>>();
Map<String, Object> map_bjgn = new HashMap<String, Object>();
map_bjgn.put("text", "报警功能");
map_bjgn.put("img", R.drawable.off);
list.add(map_bjgn);

每次都new肯定是只有最后一个了，你这不应该是new ，应该创建一个全局变量的list，然后使用list.add()方法把数据加进去，而不是每次都new，这样加载的肯定是最后一条数据，把之前的覆盖掉了