Question

I need advice is this solution acceptable and not cause overflow, I update data which read with AsyncTask, after AsyncTask finished I need to update again and again. Is this solution acceptable and safe

private class DownloadFilesTask extends AsyncTask<URL,Integer,com.ring_view.www.json.System> {

    @Override
    protected com.ring_view.www.json.System doInBackground(URL... params) {
        int count = params.length;
         URL temp=params[0];
         System system=null;
        try {
            system = Communicator.getSystem(temp);
        } catch (LoggingConnectionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONParsingErrorException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

         return system;
    }

     protected void onProgressUpdate(Integer... progress) {
         //setProgressPercent(progress[0]);
     }

     protected void onPostExecute(com.ring_view.www.json.System result) {
         txtWorkAllowedValue.setText(result.work_allowed);
         try {
            new DownloadFilesTask().execute(new URL("http://test/status-system.json"));
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
     }

 }

I first time call new DownloadFilesTask().execute(new URL(“http://test/status-system.json”)); in OvCreate method and it works fine in emulator. Is this safe or there is some more elegant solution ?

Answer 1

Yes, instantiating an AsyncTask multiple times is acceptable, example…

new DownloadFilesTask().execute(...);
...
new DownloadFilesTask().execute(...);

…is allowed.

You must not do something like the following though…

DownloadFilesTask myTask = new DownloadFilesTask();
myTask.execute(...); // This is OK
myTask.execute(...); // This will cause an exception

This is because it isn’t legal to execute the same thread twice. In the first example using new repeatedly creates a new thread for doInBackground(...) but in the second example it is trying to re-use the previous one.