Android编程实现动态更新ListView的方法

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<ListView android:id="@+id/lv"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<TextView
 android:id="@+id/text1"
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="30px"
 android:textSize="18sp"
>
</TextView>

import java.util.ArrayList;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;
publicclass main extends Activity {
/** Called when the activity is first created. */
   ListView lv;
   ArrayAdapter<String> Adapter;
   ArrayList<String> arr=new ArrayList<String>();
   @Override
 publicvoid onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
     setContentView(R.layout.main);
     lv=(ListView)findViewById(R.id.lv);
     arr.add("123");
     arr.add("234");
     arr.add("345");
     Adapter =new ArrayAdapter<String>(this,R.layout.playlist, arr);
     lv.setAdapter(Adapter);
     lv.setOnItemClickListener(lvLis);
     editItem edit=new editItem();
     edit.execute("0","第1项");//把第一项内容改为"第一项"
     Handler handler=new Handler();
     handler.postDelayed(add,3000);//延迟3秒执行
   }
   Runnable add=new Runnable(){
     @Override
 publicvoid run() {
 // TODO Auto-generated method stub
       arr.add("增加一项");//增加一项
       Adapter.notifyDataSetChanged();
     }
   };
 class editItem extends AsyncTask<String,Integer,String>{
     @Override
 protected String doInBackground(String... params) {
         arr.set(Integer.parseInt(params[0]),params[1]);
 //params得到的是一个数组，params[0]在这里是"0",params[1]是"第1项"
 //Adapter.notifyDataSetChanged();
 //执行添加后不能调用 Adapter.notifyDataSetChanged()更新UI，因为与UI不是同线程
 //下面的onPostExecute方法会在doBackground执行后由UI线程调用
 returnnull;
     }
     @Override
 protectedvoid onPostExecute(String result) {
 // TODO Auto-generated method stub
 super.onPostExecute(result);
       Adapter.notifyDataSetChanged();
 //执行完毕，更新UI
     }
   }
 private OnItemClickListener lvLis=new OnItemClickListener(){
     @Override
 publicvoid onItemClick(AdapterView<?> arg0, View arg1, int arg2,
 long arg3) {
 //点击条目时触发
 //arg2即为点中项的位置
       setTitle(String.valueOf(arr.get(arg2)));
     }
   };
}