Correct way to update progress bar while reading records from a text file - Android

Question

I'm trying to read large text files in my Application, for which I need to use AsyncTask. I adapt the code I had (which works perfectly) to read small files to work in AsyncTask. The problem that I have is to update the ProgressBar.

I'm trying to make it work with the answer to the question: android update progress bar while reading records from a text file, which reads as follows:

"What about using the file size and counting the number of bytes you read each time?"

int sizeInBytes = file.length();
int currentBytes = 0;

//READ A LINE
currentBytes += line.length();
updateProgress((currentBytes/sizeInBytes)*100);

I try to use that in my application but I can not make it work. This is my code:

private class MiTarea extends AsyncTask<String, Float, String > {

    protected void onPreExecute() {
        dialog.setProgress(0);
        dialog.setMax(100);
        dialog.show(); //Mostramos el diálogo antes de comenzar
    }

    protected String doInBackground(String... urls) {


                    if (carpeta_para_leer == "Textos"){
                        sdcard = new File( Environment.getExternalStorageDirectory().toString()+"/" + carpeta_para_leer + "/");
                    }else{
                        sdcard = new File( Environment.getExternalStorageDirectory().toString()+"/Textos/" + carpeta_para_leer + "/");
                    }


                    //Get the text file
                    File file = new File(sdcard, nombre_texto + ".txt");
                    sizeInBytes = file.length();
                    currentBytes = 0;

                    //Read text from file
                    StringBuilder text = new StringBuilder();

                    try {
                        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file), "Cp1252"));
                        String line;

                        while ((line = br.readLine()) != null) {
                            text.append(line);
                            text.append('\n');
                            currentBytes += (long)line.length(); //HERE I TRY TO UPDATE THE PROGRESSBAR 
                        }
                    }
                    catch (IOException e) {

                    }
                    String nuevoTexto = text.toString().replaceAll("\t", " ");
                    String nuevoTextoA = nuevoTexto.replaceAll("\n", " ");
                    Holmes1 = nuevoTextoA;
                    delimitadores = " ";
                    tokenHolmes1 = new StringTokenizer(Holmes1, " ");
                    arrayHolmes1 = Holmes1.split(delimitadores);

        return Holmes1;
    }

    protected void onProgressUpdate (Float... valores) {
        dialog.setProgress((int)(currentBytes/sizeInBytes)*100);
    }

    protected void onPostExecute(Integer bytes) {
        dialog.dismiss();
    }
}

Answer 1

You should call publishProgress(//your value here) into doInbackground() this will internally call onProgressUpdate

I have posted the ShortHand Example for this...take a Look to Understand how the Methods works

HERE

Hope this could Help ...