Cancel asynctask forcefully doesn't work

Question

I have an app that is included a refresh button in actionbar. When I click on it for second time, my app goes to debug view and it says my asyncClass object isn't finished yet !!!

Please let me know how can I fix my problem.

MyActivity:

public class MyActivity extends ActionBarActivity {

   private getAllDataFromServer asyncClass;    

   @Override
   protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    asyncClass = new getAllDataFromServer();
   }

   @Override
   public boolean onOptionsItemSelected(MenuItem item) {
    // TODO Auto-generated method stub
    if(item.getItemId() == R.id.action_update)
       if(asyncClass.getStatus() == Status.FINISHED || asyncClass.getStatus() == Status.RUNNING)
       {
          asyncClass.cancel(true);
       }
       if(asyncClass.getStatus() == Status.PENDING)
       {
          asyncClass.execute();
       }
    }
    return super.onOptionsItemSelected(item);
}

getAllDataFromServer:

private class getAllDataFromServer extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        pDialog = new ProgressDialog(SendCommentsHistoryActivity.this);
        pDialog.setMessage("Be patient ...");
        pDialog.setCancelable(false);
        pDialog.show();
        super.onPreExecute();
    }

    @Override
    protected Void doInBackground(Void... params) {
        if(isCancelled()) return null;
        jObject = jParser.getJSONFromUrl(TAG_URL, param);
        Log.i("JSONNNNNNNNN", jObject.toString());
        try {
            // get json array

            for (int i = 0; i < jArray.length(); i++) 
            {
                // get jsonObjects and fill database
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        fillListView();
        pDialog.dismiss();
        super.onPostExecute(result);
    }

    @Override
    protected void onCancelled() {
        // TODO Auto-generated method stub
        super.onCancelled();
    }
}

UPDATE: JSONParser class:

public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

public JSONParser() {
}

/**
 * Send POST Data to Server & Retrieve JSON From URL
 */
public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {
// Making HTTP request
try {
    // defaultHttpClient
    DefaultHttpClient httpClient = new DefaultHttpClient();
    HttpPost httpPost = new HttpPost(url);
    httpPost.setEntity(new UrlEncodedFormEntity(params,"UTF-8"));
    HttpResponse httpResponse = httpClient.execute(httpPost);
    HttpEntity httpEntity = httpResponse.getEntity();
    is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
} catch (ClientProtocolException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}
try {
    BufferedReader reader = new BufferedReader(new InputStreamReader(
            is, "UTF8"), 8);
    StringBuilder sb = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) {
        sb.append(line + "\n");
    }
    is.close();
    json = sb.toString();
} catch (Exception e) {
    Log.e("Buffer Error", "Error converting result " + e.toString());
}
try {
    jObj = new JSONObject(json);
} catch (JSONException e) {
    Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON Object
return jObj;
}

}

Error screen shot: enter image description here

Any suggestion will be appreciated ...

the problem is cancel on AsyncTask does not cancel doInBackground process. you must add condition in doInBackground process to check if the process is canceled or not — Randyka Yudhistira, Feb 24 '15 at 06:49
and FYI, you cannot force end the HttpURLConnection. try to set timeout — Randyka Yudhistira, Feb 24 '15 at 06:59
@RandykaYudhistira, I added JSONParser class to my question. please let me know how can I set timeout for HttpURLConnection. — Farshad Kazemi, Feb 24 '15 at 07:25
@FarshadKazemi [This SO post explain it](http://stackoverflow.com/questions/693997/how-to-set-httpresponse-timeout-for-android-in-java) — Randyka Yudhistira, Feb 24 '15 at 08:14

Nagaraju V · Answer 1 · 2015-02-24T07:01:14.933

0

Once try as follows

if(!asyncClass.isCancelled()) {
      asyncClass.cancel(true);
}

and in forloop of doInBackground() write

@Override
protected Void doInBackground(Void... params) {
    .......................
        // get json array

        for (int i = 0; i < jArray.length(); i++) 
        {
            // get jsonObjects and fill database

          // Escape early if cancel() is called

           if (isCancelled()) break;
        }

    } catch (JSONException e) {
        e.printStackTrace();
    }
    return null;
}

Hope this will helps you.

edited Feb 24 '15 at 07:01

answered Feb 24 '15 at 06:52

Nagaraju V

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I did it, but it doesn't fix my problem. – Farshad Kazemi Feb 24 '15 at 07:00
@FarshadKazemi i edited my answer once check have you tried like this only? – Nagaraju V Feb 24 '15 at 07:02
I used your code and change onOptionItemSelected section to if(!asyncClass.isCancelled()) asyncClass.cancel(true); ayncClass.execute(); But I get the error again – Farshad Kazemi Feb 24 '15 at 07:07
@FarshadKazemi can you update your code which error you are getting? – Nagaraju V Feb 24 '15 at 07:10
When the asynctask is cancelled as Nag showed, then the `onCancelled()` callback is called instead of `onPostExecute()`. Make sure you are cancelling the dialog and running any other cleanup code in both callbacks – cjbrooks12 Feb 24 '15 at 07:38

Cancel asynctask forcefully doesn't work

1 Answers1