Afficher la barre de progression pendant le téléchargement JSON - Android

Question

Je télécharge un très grand JSON et cela prend beaucoup de temps.
Je souhaite afficher le pourcentage de données que j'ai téléchargées.

J'ai cherché et trouvé comment afficher la progression si je télécharge un fichier mais pas JSON.

Voici comment je suis le téléchargement JSON

private String getStringFromURL(String url) { 
     String string = null; 

     try { 

      HttpClient client = new DefaultHttpClient(); 

      url = url.replace(" ", "%20"); 
      url = url.replace("|", "%7C"); 
      HttpGet get = new HttpGet(url); 
      HttpResponse response = client.execute(get); 
      if (response.getStatusLine().getStatusCode() == 200) { 
       String result = EntityUtils.toString(response.getEntity(), 
         HTTP.UTF_8); 
       if (result.toLowerCase().contains("invalid")) 
        return null; 
       result = result.replace("\r", ""); 
       result = result.replace("\n", "").replace("\t", "\\t") 
         .replace("\b", "\\b").replace("\f", "\\f") 
         .replace("&", "\\&").replace("\'", "\\'") 
         .replace(";", "\\;").replace("?", "\\?") 
         .replace("*", "\\*"); 
       string = result; 
      } 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     return string; 
    } 

Answer 1

Vous feriez mieux d'utiliser AsyncTask pour télécharger des données. Il y a un exemple de code ci-dessous. Je ne l'ai pas testé mais ça devrait marcher.

private class FetchJsonTask extends AsyncTask<Void, Void, String> { 
    private ProgressDialog progressDialog; 
    private Context context; 

    public FetchJsonTask(Context context) { 
     this.context = context; 
    } 

    @Override 
    protected void onPreExecute() { 
     // set up progress dialog 
     progressDialog = new ProgressDialog(context); 
     progressDialog.setIndeterminate(true); 
     progressDialog.setMessage("Please wait..."); 

     // show it 
     progressDialog.show(); 
    } 

    @Override 
    protected String doInBackground(Void... params) { 
     // These two need to be declared outside the try/catch 
     // so that they can be closed in the finally block. 
     HttpURLConnection urlConnection = null; 
     BufferedReader reader = null; 

     // Will contain the raw JSON response as a string. 
     String jsonStr = null; 

     try { 
      // Construct the URL somehow 
      URL url = createURL(); 

      // Create the request to MuslimSalat.com, and open the connection 
      urlConnection = (HttpURLConnection) url.openConnection(); 
      urlConnection.setRequestMethod("GET"); 
      urlConnection.connect(); 

      // Read the input stream into a String 
      InputStream inputStream = urlConnection.getInputStream(); 
      StringBuffer buffer = new StringBuffer(); 
      if (inputStream == null) { 
       // Nothing to do. 
       return null; 
      } 
      reader = new BufferedReader(new InputStreamReader(inputStream)); 

      String line; 
      while ((line = reader.readLine()) != null) { 
       // Since it's JSON, adding a newline isn't necessary (it won't affect parsing) 
       // But it does make debugging a *lot* easier if you print out the completed 
       // buffer for debugging. 
       buffer.append(line + "\n"); 
      } 

      if (buffer.length() == 0) { 
       // Stream was empty. No point in parsing. 
       return null; 
      } 
      jsonStr = buffer.toString(); 
     } catch (IOException e) { 
      Log.e(LOG_TAG, "Error ", e); 
      // If the code didn't successfully get the data, there's no point in attemping 
      // to parse it. 
      return null; 
     } finally{ 
      if (urlConnection != null) { 
       urlConnection.disconnect(); 
      } 
      if (reader != null) { 
       try { 
        reader.close(); 
       } catch (final IOException e) { 
        Log.e(LOG_TAG, "Error closing stream", e); 
       } 
      } 
     } 

     return jsonStr; 
    } 

    @Override 
    protected void onPostExecute(String jsonString) { 
     // jsonString is your result use it somehow. 
     Log.d(LOG_TAG, "Json result: " + jsonString); 

     // dismiss the progress because downloading process is finished. 
     progressDialog.dismiss(); 
    } 
} 

Vous pouvez l'appeler de votre activité, etc. fragment

FetchJsonTask fetchJsonTask = new FetchJsonTask(context); 
fetchJsonTask.execute();