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这是我的主要课程 

public class EndlessAdapterDemo extends Activity  {

    private ListView mListView;
    private ProgressDialog dialog;
    private OutletsXmlHandler mOutletXmlHandler;
    private FetchAndParseData getDownloadedData;
    private OutletListAdapter mOutletListAdapter;
    public InputStream inputStream;
    private ArrayList<Outlets> outletList;


  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.list_tab);


    mListView = (ListView) findViewById(R.id.listView1);
    mOutletXmlHandler = new OutletsXmlHandler();
    dialog = new ProgressDialog(this);
    dialog.setMessage("Loading");
    dialog.setCancelable(false);

    new MyTask().execute();  
  }
}



    **And in MyTask class i am doing following**

        public class MyTask extends AsyncTask<Void, Void, Void> {

            @Override
            protected void onPreExecute() {

                super.onPreExecute();
                dialog.show();
            }

        @Override
        protected Void doInBackground(Void... params) {

            try {                           
                getDownloadedData = (FetchAndParseData) new FetchAndParseData().execute("http://184.106.222.195/zootapi/index.php/api/outlets/searchoutlets/token/something/cityid/83/parameters/&cu=American&s=Air$Conditioned");

                inputStream = getDownloadedData.get();
                XmlUtilities.parseAndLoadData(inputStream , mOutletXmlHandler);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (ExecutionException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }


            return null;
        }

        @Override
        protected void onPostExecute(Void result) {         
            super.onPostExecute(result);

            outletList = Project.getOutletList();//Project.getOutletList();             
            mListView.setAdapter(new DemoAdapter(outletList));

            if(dialog.isShowing()){
                dialog.dismiss();
            }

        }
    }


**Now in this Demo Adpapter i am extending it with EndlessAdpater**


 class DemoAdapter extends EndlessAdapter {
    private RotateAnimation rotate=null;

    DemoAdapter(ArrayList<Outlets> outletList) {
      super(new OutletListAdapter(EndlessAdapterDemo.this, outletList));

      rotate=new RotateAnimation(0f, 360f, Animation.RELATIVE_TO_SELF,
                                  0.5f, Animation.RELATIVE_TO_SELF,
                                  0.5f);
      rotate.setDuration(600);
      rotate.setRepeatMode(Animation.RESTART);
      rotate.setRepeatCount(Animation.INFINITE);
    }

    @Override
    protected View getPendingView(ViewGroup parent) {
      View row=getLayoutInflater().inflate(R.layout.row, null);

      View child=row.findViewById(android.R.id.text1);

      child.setVisibility(View.GONE);

      child=row.findViewById(R.id.throbber);
      child.setVisibility(View.VISIBLE);
      child.startAnimation(rotate);

      return(row);
    }

    @Override
    protected boolean cacheInBackground() {
        try {                           
            getDownloadedData = (FetchAndParseData) new FetchAndParseData().execute("http://184.106.222.195/zootapi/index.php/api/outlets/fetchoutlets/token/something/cityid/76/verticalid/1");

            inputStream = getDownloadedData.get();
            XmlUtilities.parseAndLoadData(inputStream , mOutletXmlHandler);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

      return true;
    }

    @Override
    protected void appendCachedData() {

        outletList = Project.getOutletList();//Project.getOutletList();             
        mListView.setAdapter(new DemoAdapter(outletList));
   }
  }

**现在在此源代码中，当列表到达末尾时，数据已成功从 Web 服务加载到列表视图中，但以前的数据已丢失..

谁能帮帮我……我在这方面遇到了很大的麻烦**

4

1 回答 1

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您每次都在创建一个新的 DemoAdapter。

更改您的 appendCachedData 以获取包装的适配器，然后向其中添加额外的元素：

@Override
protected void appendCachedData() {
    OutletListAdapter adptr = (OutletListAdapter) getWrappedAdapter();
    if (outletList!=null) {
        for (<T> addThis : outletList) {
            adptr.add(addThis);
        }
    }
}
于 2012-06-08T13:04:15.423 回答