How to update Progressbar in android while downloading and inserting JSON data in SQLite?

Question

The background or thread operation of downloading and inserting JSON data into database works fine but as I also want to update my ProgressBar when the data insertion operation keeps updating. My problem is, it starts with Zero percent and dismisses when the whole operation is completed without any update in percentage value.

Sync Fragment:

String value; //defined globally

private class JsonParse extends AsyncTask<String, String, String> {

    Context mcontext;
    private ProgressDialog progressDialog;

    public JsonParse(Context context) {
        this.mcontext = context;
    }

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

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

        progressDialog = new ProgressDialog(mcontext);

        progressDialog.setTitle("Downloading"); // Setting Title
        progressDialog.setMessage("Please wait"); // Setting Message
        progressDialog.setIndeterminate(false);
        progressDialog.setMax(100);
        progressDialog.setCancelable(false);
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        progressDialog.setButton(DialogInterface.BUTTON_NEGATIVE, mcontext.getString(R.string.cancel_btn), new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });

        progressDialog.show();
    }

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

        String choice = params[0];
        final String url = BASE_URL + "" + VERSION + "" + METHOD + "";

        StringRequest request = new StringRequest(Request.Method.POST, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {

                        Log.i("response", url + "response:" + response);

                        try {
                            JSONObject object = new JSONObject(response);
                            JSONArray jsonArray = object.getJSONArray(METHOD + "");

                            long counter = 0;
                            int size = jsonArray.length();

                            for (int i = 0; i <= size; i++) {

                                final JSONObject jsonObject = jsonArray.getJSONObject(i);

                                counter++;
                                int percent = (int) ((counter * 100) / size);
                                value = percent + "";

                                onProgressUpdate(value);

                                Log.i("view_", "size: " + size + " " + "counter: " + counter + " " + "percent: " + percent + "%");

                                switch (choice) {

                                    case "deaths":

                                        String id_d = jsonObject.getString("id");
                                        String family_id = jsonObject.getString("family_id");
                                        String death_one_year = jsonObject.getString("death_one_year");
                                        String no_of_deaths = jsonObject.getString("no_of_death");
                                        String cause = jsonObject.getString("cause");
                                        String cause_other = jsonObject.getString("cause_other");
                                        String ward_id_d = jsonObject.getString("ward_id");
                                        String has_error_d = jsonObject.getString("has_error");
                                        String updated_by_d = jsonObject.getString("updated_by");
                                        String updated_at_d = jsonObject.getString("updated_at");
                                        String created_at = jsonObject.getString("created_at");
                                        String uuid_d = jsonObject.getString("uuid");

                                        dbHelper.SyncDeath(Integer.parseInt(id_d), family_id, death_one_year, no_of_deaths, cause, cause_other,
                                                ward_id_d, has_error_d, updated_by_d, updated_at_d, created_at, uuid_d);

                                        death_txt.setTextColor(getResources().getColor(R.color.colorPrimary));
                                        death_txt.setText(R.string.synced);

                                        break;
                                }
                            }
                            return;

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                        progressDialog.dismiss();
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
                Toast.makeText(getContext(), "Server Error, Please Try Again!!", Toast.LENGTH_SHORT).show();
            }
        });

        requestQueue.add(request);

        publishProgress(value);

        Log.i("view_percent_value", value); // Getting null value

        /*for (int i = 0; i <= 100; i++){
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            publishProgress(String.valueOf(i));
        }*/

        return null;
    }

    @Override
    protected void onProgressUpdate(String... values) {

        progressDialog.setProgress(Integer.parseInt(values[0]));
        value = values[0]; // Tried to update this "value" i.e. set globally but can't update

        Log.i("view_values", values[0] + "");
        super.onProgressUpdate(values);
    }

    @Override
    protected void onPostExecute(String result) {

    }
}

The above-commented code:

 /*for (int i = 0; i <= 100; i++){
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            publishProgress(String.valueOf(i));
        }*/

helps me update ProgressBar but it is not updating in Realtime. In my case, the parameter passed in publishprogress(); i.e. "value" which is defined globally is not getting updated value from the loop. As I guess, it may be the case using for-loop inside try-catch but I can't find the way how to pass that value to publishprogress(); method.

The Log view:

Log.i("view_", "size: " + size + " " + "counter: " + counter + " " + "percent: " + percent + "%");

is updating the percentage value in real-time. Like this:

Please help me to figure out this problem. I'm stuck with this problem from couple of weeks. Thank you in advance!!

Answer 1

First, according to android documents never call onPreExecute(), onPostExecute(Result), doInBackground(Params...), onProgressUpdate(Progress...) manually. (you are calling onProgressUpdate in doInBackground manually)

Second, move publishProgress(value); to for loop inside try block.

Answer 2

Trying setting value of your progress in onProgressUpdate() function.

Follow this link for reference: android how to work with asynctasks progressdialog