android - studio - ¿Cómo recupero los datos de AsyncTasks doInBackground()?

onpreexecute method in android

Question

Mantendré este tan simple como pueda.

Tengo un método en mi capa de control que usa una clase CallServiceTask que extiende AsyncTask . Al llamar al nuevo CallServiceTask().execute(parameters)
¿Cómo recupero los datos devueltos de doInBackground ? Todos los tutoriales que he encontrado utilizan la clase que extiende AsyncTask directamente de su Activity .
Mi problema es un poco más complejo que eso.
Todo lo que quiero es tomar el Object[] devuelto por doInBackground y establecerlo en los miembros de datos privados de mi clase RestClient .

CallServiceTask tiene este aspecto:

    private class CallServiceTask extends AsyncTask<Object, Void, Object[]>
{

    protected Object[] doInBackground(Object... params) 
    {
        HttpUriRequest req = (HttpUriRequest) params[0];
        String url = (String) params[1];

        return executeRequest(req, url);
    }
}

Y mi clase RestClient se ve así:

public class RestClient
{

private ArrayList <NameValuePair> params;
private ArrayList <NameValuePair> headers;

private JSONObject jsonData;

private Object[] rtnData;

private String url;

private boolean connError;

public int getResponseCode() {
    return responseCode;
}

/**
 * 
 * @return  the result of whether the login was successful by looking at the response parameter of the JSON object. 
 */
public Boolean DidLoginSucceed()
{
    // Will Crash on socket error
        return ((JSONObject) rtnData[0]).optBoolean("response");
}

public String GetToken()
{
    return jsonData.optString("token");
}

public RestClient(String url)
{
    this.url = url;
    params = new ArrayList<NameValuePair>();
    headers = new ArrayList<NameValuePair>();
    rtnData = new Object[]{ new JSONObject() , Boolean.TRUE  };
}

public void AddParam(String name, String value)
{
    params.add(new BasicNameValuePair(name, value));
}

public void AddHeader(String name, String value)
{
    headers.add(new BasicNameValuePair(name, value));
}

/**
 * This method will execute, call the service and instantiate the JSON Object through executeRequest().
 * 
 * @param method    an enum defining which method you wish to execute.
 * @throws Exception
 */
public void ExecuteCall(RequestMethod method) throws Exception
{
    Object[] parameters = new Object[]{ new HttpGet() , new String("") };
    switch(method) {
        case GET:
        {
            //add parameters
            String combinedParams = "";
            if(!params.isEmpty()){
                combinedParams += "?";
                for(NameValuePair p : params)
                {
                    String paramString = p.getName() + "=" + URLEncoder.encode(p.getValue());
                    if(combinedParams.length() > 1)
                    {
                        combinedParams  +=  "&" + paramString;
                    }
                    else
                    {
                        combinedParams += paramString;
                    }
                }
            }

            HttpGet request = new HttpGet(url + combinedParams);

            //add headers
            for(NameValuePair h : headers)
            {
                request.addHeader(h.getName(), h.getValue());
            }
            parameters[0] = request;
            parameters[1] = url;

            new CallServiceTask().execute(parameters);

            jsonData = ((JSONObject) rtnData[0]).optJSONObject("data");
            connError = (Boolean) rtnData[1];
            break;

        }
        case POST:
        {
            HttpPost request = new HttpPost(url);

            //add headers
            for(NameValuePair h : headers)
            {
                request.addHeader(h.getName(), h.getValue());
            }

            if(!params.isEmpty()){
                request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
            }
            new CallServiceTask().execute(request, url);
            break;
        }
    }
}

private Object[] executeRequest(HttpUriRequest request, String url)
{
    HttpClient client = new DefaultHttpClient();
    client = getNewHttpClient();

    HttpResponse httpResponse;

    try {
        httpResponse = client.execute(request);
        HttpEntity entity = httpResponse.getEntity();

        if (entity != null) {

            InputStream instream = entity.getContent();
            String response = convertStreamToString(instream);
            try {
                rtnData[0] = new JSONObject(response);
                rtnData[1] = false;

            } catch (JSONException e1) {
                rtnData[1] = true;
                e1.printStackTrace();
            }

            // Closing the input stream will trigger connection release
            instream.close();
        }

    } catch (ClientProtocolException e)  {
        client.getConnectionManager().shutdown();
        e.printStackTrace();
    } catch (IOException e) {
        client.getConnectionManager().shutdown();
        e.printStackTrace();
    }
    return rtnData;
}


private static String convertStreamToString(InputStream is) {

    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();

    String line = null;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line + "/n");
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return sb.toString();
}

/**
 * Custom HTTP Client accepting all SSL Certified Web Services.
 * 
 * @return n HttpClient object.
 */
public HttpClient getNewHttpClient() {
    try {
        KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
        trustStore.load(null, null);

        SSLSocketFactory sf = new MySSLSocketFactory(trustStore);
        sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);

        SchemeRegistry registry = new SchemeRegistry();
        registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
        registry.register(new Scheme("https", sf, 443));

        ClientConnectionManager ccm = new ThreadSafeClientConnManager(params, registry);

        return new DefaultHttpClient(ccm, params);
    } catch (Exception e) {
        return new DefaultHttpClient();
    }
}

Answer 1

Como @ saad-farooq mencionó, puedes usar la interface para eso. Así que puedes usar interface o definir el tuyo:

public interface ClientIF {

    public void onResponseReceived(Object result);

}

entonces necesitas implementarlo en tu CallServiceTask

public abstract class CallServiceTask extends AsyncTask<Object, Void, Object[]> 
    implements ClientIF
{
    Activity activity;

    CallServiceTask(Activity activity) {
        this.activity = activity;
    }

    public abstract void onResponseReceived(Object result); 

    protected Object[] doInBackground(Object... params) 
    {
        HttpUriRequest req = (HttpUriRequest) params[0];
        String url = (String) params[1];
        return executeRequest(req, url);
    }

    protected onPostExecute(Object result) {
        onResponseReceived(result);
    }
}

tenga en cuenta que el costructor se cambia para que pueda llamar desde cada clase de actividad . Luego haz la instancia de esta clase en tu RestClient

public class RestClient
{
CallServiceTask service = new CallServiceTask() {
    @Override
    public void onResponseReceived(Object result) {
    // TODO Auto-generated method stub

    }
};

}

Answer 2

La única manera de hacer esto es usando un CallBack. Puedes hacer algo como esto:

new CallServiceTask(this).execute(request, url);

Luego, en su CallServiceTask, agregue una variable de clase local y llame a un método de esa clase en su onPostExecute:

private class CallServiceTask extends AsyncTask<Object, Void, Object[]>
{
    RestClient caller;

    CallServiceTask(RestClient caller) {
        this.caller = caller;
    }


    protected Object[] doInBackground(Object... params) 
    {
        HttpUriRequest req = (HttpUriRequest) params[0];
        String url = (String) params[1];
        return executeRequest(req, url);
    }

    protected onPostExecute(Object result) {
        caller.onBackgroundTaskCompleted(result);
    }
}

Luego simplemente use el Objeto como quiera en el método onBackgroundTaskCompleted() en su clase RestClient.

Una solución más elegante y extensible sería utilizar interfaces. Para una implementación de ejemplo vea this biblioteca. Acabo de empezar, pero tiene un ejemplo de lo que quieres.

Answer 3

Puede usar get() para recuperar su value/object de AsyncTask .

new CallServiceTask().execute(parameters).get();

Esto le devolverá el resultado computed que está devolviendo. Pero esto bloqueará su interfaz de usuario hasta que se complete el proceso de fondo.

Otra opción es crear una Interfaz o BroadcastReceiver que le devuelva el valor tan pronto como se doInBackground() su doInBackground() . Había creado una demo para el mismo usando Interface y BroadcastReceiver, puedes verificar si desde mi github

Además, al utilizar el segundo enfoque, su interfaz de usuario no se bloqueará.

Answer 4

private void walletStatements() {
        JSONObject post_search = new JSONObject();
        try {

            post_search.put("username", getUserName);


        } catch (JSONException e) {
            e.printStackTrace();
        }
        if (post_search.length() > 0) {
            try {
               new Getwalletstatements().execute(String.valueOf(post_search));

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

        }
    }


    class Getwalletstatements extends AsyncTask<String, String, String> {
        String JsonResponse = null;
        ProgressDialog dialog;

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

            dialog = new ProgressDialog(ReportsActivity.this);
            dialog.setMessage("Please Wait...");
            dialog.setCancelable(false);
            dialog.show();
        }

        @Override
        protected String doInBackground(String... params) {
            String JsonDATA = params[0];
            HttpURLConnection urlConnection = null;
            BufferedReader reader = null;
            URL url = null;

            try {
                url = new URL(Constant.url+"GetReports_v9.php");
                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setDoOutput(true);                // is output buffer writter
                urlConnection.setRequestMethod("POST");
                urlConnection.setRequestProperty("Content-Type", "application/json");
                urlConnection.setRequestProperty("Accept", "application/json");//set headers and method
                Writer writer = new BufferedWriter(new OutputStreamWriter(urlConnection.getOutputStream(), "UTF-8"));
                writer.write(JsonDATA);// json data
                writer.close();

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

                while ((inputLine = reader.readLine()) != null)
                    buffer.append(inputLine + "/n");

                if (buffer.length() == 0) {                    // Stream was empty. No point in parsing.
                    return null;
                }

                JsonResponse = buffer.toString();


                return JsonResponse;

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (ProtocolException e) {
                e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (urlConnection != null) {
                    urlConnection.disconnect();
                }
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (final IOException e) {

                    }
                }
            }


            return null;
        }

        @Override
        protected void onPostExecute(String s) {

            if (JsonResponse != null) {
                try {
                    NetworkIN.iv= Constant.iv;
                    NetworkIN.change=Constant.key;
                    NetworkIN mCrypt=new NetworkIN();
                    String decrypted = new String( mCrypt.decrypt(JsonResponse.trim()) );

                    if(decrypted!=null){
                        JSONObject ordersHistory = new JSONObject(decrypted);
                        msg = ordersHistory.getString("msg");

                        JSONArray jsonArray = ordersHistory.getJSONArray("PPDetails");

                        ordersCount = jsonArray.length();
                        //for (int j = 0; j < jsonArray.length(); j++)
                        for (int j = jsonArray.length() - 1; j >= 0; j--)
                        {
                            JSONObject jsonObject = jsonArray.getJSONObject(j);


                            String message,total_in,inType ;

                            total_in =jsonObject.getString("total_in");
                            inType =jsonObject.getString("in_type");
                            message="Congratulations your wallet is credited by Rs."+total_in+" because of "+inType;
                            ReportsPojo reportsPojo = new ReportsPojo(jsonObject.getString("reg_id"),
                                    jsonObject.getString("username"),
                                    jsonObject.getString("transfer_from"),
                                    jsonObject.getString("transfer_to"),
                                    jsonObject.getString("total_in"),
                                    jsonObject.getString("tds"),
                                    jsonObject.getString("in_amount") ,
                                    jsonObject.getString("out_amount"),
                                    jsonObject.getString("in_type"),
                                    jsonObject.getString("created_on"),
                                    message);

                            reportsItems.add(reportsPojo);
                        }
                    }else{

                    }


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

                if (msg.equals("Success")) {

                    reportsAdapter = new ReportsAdapter(ReportsActivity.this, reportsItems);
                    reportsListview.setAdapter(reportsAdapter);

                } else {
                    Toast.makeText(ReportsActivity.this, "Sorry "+msg, Toast.LENGTH_LONG).show();

                }
                dialog.dismiss();
            } else {
                dialog.dismiss();
            }
        }

Answer 5

public class MyAsyncTask extends AsyncTask<String, Void, String> {  

    @Override    
    protected void onPreExecute() {
        //showProgressDialog
        dialog = new ProgressDialog(this);
        dialog.setMessage("Loading........");
        dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        dialog.show();
    }

    @Override    
    protected String doInBackground(String... strings) {
      HttpURLConnection httpURLConnection;
      BufferedReader reader;
      int responseCode ;

        try {
            URL url = new URL(YOUR_URL);
            URLConnection urlConnection = url.openConnection();
            httpURLConnection = (HttpURLConnection) urlConnection;
            httpURLConnection.setRequestMethod("GET");
            httpURLConnection.setDoOutput(true);

            responseCode = httpURLConnection.getResponseCode();
            InputStream inputStream = httpURLConnection.getInputStream();
            if (inputStream != null) {
                if (responseCode == 200) {
                    reader = new BufferedReader(new InputStreamReader(inputStream));
                    StringBuilder buffer = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        buffer.append(line);
                    }
                    return buffer.toString();
                }
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override    
    protected void onPostExecute(String result) {
        progressDialog.dismiss();
        // Fetch Your Data Add Your Code Here
    }
}

Answer 6

public class getOperators extends AsyncTask<Void, Void, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        items = new ArrayList();
        dialog = new ProgressDialog(PrepaidOperatorsListActivity.this);
        dialog.setMessage("Please Wait...");
        dialog.setCancelable(false);
        dialog.show();
    }



    @Override
    protected String doInBackground(Void... params) {
        BufferedReader reader;
        StringBuffer buffer;
        String res = null;

        try {
            URL url = new URL("");
            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            con.setReadTimeout(40000);
            con.setConnectTimeout(40000);
            con.setRequestMethod("GET");
            con.setRequestProperty("Content-Type", "application/json");
            int status = con.getResponseCode();
            InputStream inputStream;
            if (status == HttpURLConnection.HTTP_OK) {
                inputStream = con.getInputStream();
            } else {
                inputStream = con.getErrorStream();
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));
            buffer = new StringBuffer();
            String line = "";
            while ((line = reader.readLine()) != null) {
                buffer.append(line);
            }
            res = buffer.toString();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return res;
    }
    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        System.out.println("JSON RESP:" + s);
        String response = s;
        try {

            JSONObject ecomerrce = new JSONObject(response);
            JSONArray jsonArray = ecomerrce.getJSONArray("prepaid_operators");

            for (int j = 0; j < jsonArray.length(); j++) {
                JSONObject jsonObject = jsonArray.getJSONObject(j);

                PrepaidOperatorsPojo prepaidOperatorsPojo = new PrepaidOperatorsPojo(jsonObject.getString("operator_name"), jsonObject.getString("operator_code"), jsonObject.getString("operator_display_comission"), jsonObject.getString("operator_calculate_comission"));
                items.add(prepaidOperatorsPojo);

            }
            if (items.size() > 0) {
                dialog.dismiss();
                prepaidOperatorListAdapter = new PrepaidOperatorListAdapter(PrepaidOperatorsListActivity.this, items);
                rvPrepaidOperatorList.setAdapter(prepaidOperatorListAdapter);

            } else {
                dialog.dismiss();
                Toast.makeText(PrepaidOperatorsListActivity.this, "No Data to display", Toast.LENGTH_SHORT).show();
            }

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