等待ListView数据

1 回答

• 0

  尝试以下代码

  public class YourActivity extends ListActivity{
  private          ProgressDialog     progressBar;
  private          Animation          rotation;
  private          DownloadXmlTask    downloadXmlTask;
  private          Boolean            Loading=false;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      // TODO Auto-generated method stub
      super.onCreate(savedInstanceState);
      setContentView(R.layout.your_activity_main);        
      doDownload();              
  }
  
  private void doDownload()
  {
          if ( isConnectedToInternet() ){
              downloadXmlTask=new DownloadXmlTask();  
              downloadXmlTask.execute();
  
          }
          else
                       Toast.makeText(YourActivity.this,"faild connection", 1).show();
  }
  
  @Override
  protected void onPause() {
      // TODO Auto-generated method stub
      super.onPause();
      if (Loading==true)
          stopLoadingAndDownloading();
  }
  //=====================
  //New Class Starts Here
  //=====================
  
  class IconicAdapter extends ArrayAdapter<String> {
  //your class
  
  }
  
  public void onListItemClick(ListView parent, View v, int position, 
          long id){
          //do something
      }
  
  /*-----------------------------------------------------------------------------------
   *  Showing / Stopping progress dialog which is showing loading animation
   *  ---------------------------------------------------------------------------------*/
  private void showLoading(){
      progressBar = ProgressDialog.show(YourActivity.this, "", "");
      progressBar.setContentView(R.layout.YourLayout);
      progressBar.setCancelable(false);   
      //and another thing that need for progressBar
      Loading=true;
  }
  
  private void stopLoadingAndDownloading() {
      Loading=false;
  
      if(progressBar.isShowing())
          progressBar.dismiss();
      if (downloadXmlTask != null && downloadXmlTask.getStatus() != AsyncTask.Status.FINISHED)
          downloadXmlTask.cancel(true);
  }
  
  
  public boolean isConnectedToInternet(){
      ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
      NetworkInfo netInfo = cm.getActiveNetworkInfo();
      if (netInfo != null && netInfo.isConnectedOrConnecting()) {
          return true;
      }
      return false;
  }
  
  /*********************************************************
   * this class is a useful class that prevent from crashing
   *  when download of data take very long time
   *********************************************************/
  
  private class DownloadXmlTask extends AsyncTask<Void, Void, String> {
  
      @Override
      protected void onPreExecute() {
          showLoading();
      }
  
      @Override
      protected String doInBackground(Void... esult) {
          //doing your download from internet
          return msg;
      }
  
      @Override
      protected void onPostExecute(String result) {
          //do something  
          setListAdapter(new IconicAdapter());        
          stopLoadingAndDownloading();
      }
  }
  }
  

  回复于 2024-04-24T21:54:14+08:00