notifyDataSetChanged

notifyDataSetChanged 动态更新listview

有时候我们需要修改已经生成的列表，添加或者修改数据，notifyDataSetChanged() 可以在修改适配器绑定的数组后， 不用重新刷新Activity. 通知Activity更新ListView . 今天的 例子就是通过 Handler AsyncTask 两种方式来动态更新ListView .

布局 main.xml

<?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>

ListView列表布局playlist.xml:

<?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>

1 import java.util.ArrayList;

2

3 import android.app.Activity;

4 import android.os.AsyncTask;

5 import android.os.Bundle;

6 import android.os.Handler;

7 import android.view.View;

8 import android.widget.AdapterView;

9 import android.widget.ArrayAdapter;

10 import android.widget.ListView;

11 import android.widget.AdapterView.OnItemClickListener;

12

13 public class main extends Activity {

14 /** Called when the activity is first created. */

15 ListView lv;

16 ArrayAdapter<String> Adapter;

17 ArrayList<String> arr=new ArrayList<String>();

18 @Override

19 public void onCreate(Bundle savedInstanceState) {

20 super.onCreate(savedInstanceState);

21 setContentView(R.layout.main);

22 lv=(ListView)findViewById(R.id.lv);

23 arr.add("123");

24 arr.add("234");

25 arr.add("345");

26 Adapter = new ArrayAdapter<String>(this,R.layout.playlist, arr);

27 lv.setAdapter(Adapter);

28 lv.setOnItemClickListener(lvLis);

29 editItem edit= new editItem();

30 edit.execute("0","第1项");//把第一项内容改为"第一项"

31 Handler handler=new Handler();

32 handler.postDelayed(add,3000);//延迟3秒执行

33 }

34 Runnable add=new Runnable(){

35

36 @Override

37 public void run() {

38 // TODO Auto-generated method stub

39 arr.add("增加一项");//增加一项

40 Adapter.notifyDataSetChanged();

41 }

42 };