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)));     }   };}