从文本文件中读取记录时更新进度条的正确方法 - Android

Question

我正在尝试在我的应用程序中读取大型文本文件，为此我需要使用 AsyncTask。我调整了我拥有的代码（完美运行）来读取小文件以在 AsyncTask 中工作。我遇到的问题是更新 ProgressBar。

我正在尝试使其与问题的答案一起工作：android update progress bar while reading records from a text file，内容如下：

“如何使用文件大小并计算每次读取的字节数？”

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

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

我尝试在我的应用程序中使用它，但我无法让它工作。 这是我的代码：

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

您应该将publishProgress(//your value here) 调用到doInbackground() 这将在内部调用onProgressUpdate

我已经为此发布了速记示例...看看以了解方法的工作原理

HERE

希望这可以帮助...