<?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>

package com.pocketdigi;
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;
public class main extends Activity {
 /** Called when the activity is first created. */
  ListView lv;
  ArrayAdapter<String> Adapter;
  ArrayList<String> arr=new ArrayList<String>();
 @Override
 public void 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
    public void 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
      return null;
    }
    @Override
    protected void 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
    public void 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)));
    }
 };
}