SimpleAdapter获取网络数据并填充LISTVIEW

因为安卓4不支持在主线程访问网络，就使用了Handler，可以正常获取数据并填充TEXTVIEW，但在使用SimpleAdapter并填充LISTVIEW时却没有反应，请问是什么原因？
private TextView tv = null;
private Button btn = null;
private ListView lv = null;
private SimpleAdapter sa = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.tv1);
btn = (Button) findViewById(R.id.button1);
lv = (ListView) findViewById(R.id.ls);
tv.setText("测试listview");
lv.setAdapter(sa);// HandlerThread ht=(HandlerThread)
final Handler myhandler = new Handler() {
public void handleMessage(Message msg) {
if (msg.what == 1) {
System.out.println("--------------->" + msg.obj);
sa = (SimpleAdapter) msg.obj;
sa.notifyDataSetChanged();
tv.setText((String) msg.obj.toString());
}
}
};
btn.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
new Thread() {
public void run() {
try {
Thread.sleep(2000);
} catch (Exception e) {
// TODO: handle exception
}

Message msg = new Message();
msg.what = 1;
ArrayList> al = new ArrayList>();
HashMap hm = new HashMap();
hm.put("name", "wfgdz");
hm.put("phone", "138238");
al.add(hm);
sa = new SimpleAdapter(MainActivity.this, al,
R.layout.listview_item, new String[] { "name",
"phone" }, new int[] { R.id.nametv,
R.id.phonetv });
msg.obj = sa;
myhandler.sendMessage(msg);
}
}.start();
}
});
}

lv（你的listview）没有setAdapter,所以没作用。在sa.notifyDataSetChanged();执行之前，调用lv.setAdapter(sa);

一般你的视图适配器还有一个类似于list的存储数据list 通过把数据添加到list，然后调用适配器的一个方法通知视图更新 adapter.notifydatasetchanged();