How to run AsyncTask every X second in Android Studio?

Question

I'm executing AsyncTask that fetch data from my web host. In order for me to retrieve data, I need to re-open my app. How can I fetch data every second? I know that AsyncTask could only be executed once, but I needed it not only for my app but also to learn about this problem. Hope to learn from you guys.

By the way this is my code:

class AsyncDataClass2 extends AsyncTask<String, Void, String>
{

    @Override
    protected String doInBackground(String... params) {
        HttpParams httpParameters = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(httpParameters, 5000);
        HttpConnectionParams.setSoTimeout(httpParameters, 5000);

        HttpClient httpClient = new DefaultHttpClient(httpParameters);
        HttpPost httpPost = new HttpPost(params[0]);

        String jsonResult = "";
        try
        {
            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
            nameValuePairs.add(new BasicNameValuePair("username", params[1]));
            nameValuePairs.add(new BasicNameValuePair("password", params[2]));
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            HttpResponse response = httpClient.execute(httpPost);
            jsonResult = inputStreamToString(response.getEntity().getContent()).toString();

        }
        catch (ClientProtocolException e)
        {
            e.printStackTrace();
        }

        catch (IOException e)
        {
            e.printStackTrace();
        }
        return jsonResult;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected void onPostExecute(String result) {

        if (result.equals("") || result == null)
        {
            Toast msg = Toast.makeText(MapsActivity.this, "connection failed", Toast.LENGTH_LONG);
            msg.setGravity(Gravity.CENTER, 0, 0);
            msg.show();
        }

        else
        {
            Toast msg = Toast.makeText(MapsActivity.this, "connected", Toast.LENGTH_LONG);
            msg.setGravity(Gravity.CENTER,0,0);
            msg.show();
        }

        try {
            JSONArray json = new JSONArray(result);

            for (int i = 0; i < json.length(); i++) {
                JSONObject e = json.getJSONObject(i);
                String point = e.getString("Point");

                String[] point2 = point.split(",");

                String devStatus = e.getString("Status");   //now, let's process the Status...
                String strOwner = e.getString("Owner");     //now, let's process the owner...

                //==============================================================================


                if (devStatus.equals("fire")) {
                    IsThereFire=true;
                }

            } //---End of FOR LOOP---//


        }//---end of TRY---//

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

    private StringBuilder inputStreamToString(InputStream is)
    {
        String rLine = "";
        StringBuilder answer = new StringBuilder();
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        try
        {
            while ((rLine = br.readLine()) != null)
            {
                answer.append(rLine);
            }
        }

        catch (IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return answer;
    }
}

EDIT:

Sir, this is the timer I used..

///---CODE for the TIMER that ticks every second and synch to database to update status---///
    Thread t = new Thread() {

        @Override
        public void run() {
            try {
                while (!isInterrupted()) {
                    Thread.sleep(1000);
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            // HERE IS THE ACTUAL CODE WHERE I CALL THE ASYNCDATACLASS2
                            AsyncDataClass2 performBackgroundTask = new AsyncDataClass2();
                            // PerformBackgroundTask this class is the class that extends AsynchTask
                            performBackgroundTask.execute();
                        }
                    });
                }
            } catch (InterruptedException e) {
            }
        }
    };

    t.start();
    //---------------------------------------------------------------//

Answer 1

if you need to execute a task at fixed interval of time you can use a Timer with a TimerTask. It runs on different thread than the UI thread, meaning that you can run your http call directly in it. You can find the documentation here

Answer 2

I do not think that's a really good idea to proceed like this but you can do it, of course with an simple TimerTask (tutorial there)

Basically, it would look like this:

public class MyTimerTask extends TimerTask {
    @Override
    public void run() {
        // Just start your AsyncTask and proceed, I didn't adapt the code to your task
        new AsyncDataClass2().execute()
    }
}

Your Logic calls it:

TimerTask timerTask = new MyTimerTask();
 // They're ms: 1000ms = 1s
 timer.scheduleAtFixedRate(timerTask, 0, 1000);
 timer.start();

You cancel it when you destroy your Fragment/Activity

timer.cancel();

Answer 3

I think you should try to use TimerTask or a job scheduler.

Lots of information about job schedulers can be found here and here.

Answer 4

Check this:

Timer timer;

private void startTimer() {
    timer = new Timer();
    timer.scheduleAtFixedRate(new TimerTask() {
        public void run() {
           new AsyncDataClass2  adc = new AsyncDataClass2("u","p");
           adc.execute();
        }
    }, 0, 1000);
}

Then in onCreate() you write:

startTimer();

Although, you should consider others comments, they're meaningful, requesting updates from web server every second in AsyncTask, it's not so good thing to do.