<?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項");//把第一項內容改為"第一項"   Handler handler=new Handler();   handler.postDelayed(add,3000);//延遲3秒執行 } Runnable add=new Runnable(){    @Override    public void run() {      // TODO Auto-generated method stub      arr.add("增加一項");//增加一項      Adapter.notifyDataSetChanged();    }    }; class editItem extends AsyncTask<String,Integer,String>{    @Override    protected String doInBackground(String... params) {        arr.set(Integer.parseInt(params[0]),params[1]);        //params得到的是一個數組，params[0]在這里是"0",params[1]是"第1項"        //Adapter.notifyDataSetChanged();        //執行添加后不能調用 Adapter.notifyDataSetChanged()更新UI，因為與UI不是同線程        //下面的onPostExecute方法會在doBackground執行后由UI線程調用      return null;    }    @Override    protected void onPostExecute(String result) {      // TODO Auto-generated method stub      super.onPostExecute(result);      Adapter.notifyDataSetChanged();      //執行完畢，更新UI    } } private OnItemClickListener lvLis=new OnItemClickListener(){    @Override    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,        long arg3) {      //點擊條目時觸發      //arg2即為點中項的位置      setTitle(String.valueOf(arr.get(arg2)));    } };}