ListView数据的分批加载 - Blacksky

 1 public class MainActivity extends Activity {
 2     private ListView listView;
 3     private List<String> data = new ArrayList<String>();
 4     ArrayAdapter<String> adapter;
 5     View footer;
 6     
 7     @Override
 8     public void onCreate(Bundle savedInstanceState) {
 9 
10         super.onCreate(savedInstanceState);
11         setContentView(R.layout.main);
12         
13         footer = getLayoutInflater().inflate(R.layout.footer, null);
14         
15         listView = (ListView) this.findViewById(R.id.listView);
16         listView.setOnScrollListener(new ScrollListener());
17         
18         data.addAll(DataService.getData(0, 20));        
19         adapter = new ArrayAdapter<String>(this, R.layout.listview_item, R.id.textView, data);
20         listView.addFooterView(footer);//添加页脚(放在ListView最后)
21         listView.setAdapter(adapter);
22         listView.removeFooterView(footer);
23     }
24     
25     private int number = 20;//每次获取多少条数据
26     private int maxpage = 5;//总共有多少页
27     private boolean loadfinish = true;
28 
29     private final class ScrollListener implements OnScrollListener{
30 
31         public void onScrollStateChanged(AbsListView view, int scrollState) {
32             Log.i("MainActivity", "onScrollStateChanged(scrollState="+ scrollState+ ")");
33         }
34         
35         public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
36             Log.i("MainActivity", "onScroll(firstVisibleItem="+ firstVisibleItem+ ",visibleItemCount="+
37                     visibleItemCount+ ",totalItemCount="+ totalItemCount+ ")");
38             
39             final int loadtotal = totalItemCount;
40             int lastItemid = listView.getLastVisiblePosition();//获取当前屏幕最后Item的ID
41             
42             if((lastItemid+1) == totalItemCount){//达到数据的最后一条记录
43                 if(totalItemCount > 0){
44                     //当前页
45                     int currentpage = totalItemCount%number == 0 ? totalItemCount/number : totalItemCount/number +1;
46                     int nextpage = currentpage + 1;//下一页
47                     if(nextpage <= maxpage && loadfinish){
48                         loadfinish = false;
49                         listView.addFooterView(footer);
50                         
51                         new Thread(new Runnable() {                        
52                             public void run() {
53                                 try {
54                                     Thread.sleep(3000);
55                                 } catch (InterruptedException e) {
56                                     e.printStackTrace();
57                                 }
58                                 List<String> result = DataService.getData(loadtotal, number);
59                                 handler.sendMessage(handler.obtainMessage(100, result));
60                             }
61                         }).start();
62                     }        
63                 }
64                         
65             }
66         }
67     }
68     
69     Handler handler = new Handler(){
70         public void handleMessage(Message msg) {
71             data.addAll((List<String>) msg.obj);
72             adapter.notifyDataSetChanged();//告诉ListView数据已经发生改变，要求ListView更新界面显示
73             if(listView.getFooterViewsCount() > 0) listView.removeFooterView(footer);
74             loadfinish = true;
75         }        
76     };
77     
78 }

 1 public class DataService {
 2 
 3     public static List<String> getData(int offset, int maxResult){//分页 limit 0,20
 4         List<String> data = new ArrayList<String>();
 5         for(int i=0 ; i < 20 ; i++){
 6             data.add("ListView数据的分批加载"+ i);
 7         }
 8         return data;
 9     }
10 }

posted on 2012-09-03 11:20 Blacksky 阅读(1555) 评论(0) 编辑收藏举报

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