How to use AsyncTask to show a ProgressDialog while doing background work in Android? [duplicate]

Question

Possible Duplicate:
Updating progress dialog in Activity from AsyncTask

I am developing my first Android App and I need a ProgressDialog to be showed while a background task, in this case just a http call on the server, happens. I did a bit of studying on this and also have already checked other threads related to this subject.

http://developer.android.com/reference/android/os/AsyncTask.html

Android show ProgressDialog until activity UI finished loading

Android SplashScreen

http://android-developers.blogspot.com/2009/05/painless-threading.html

Among others.

Than I got to write a bit of code:

1) In My Activity I declare a variable to be of type ProgressDialog

public class LoginActivity extends Activity {      public static final String TAG = "LoginActivity";      protected ProgressDialog progressDialog;  ... 

2) I have also written an inner class to extend AsyncTask as required, here in the doInBackGround is where I call a static method which actually do the POST http request to the server, in the server side I have blocked the server response 20s to validate the progress dialog.

class EfetuaLogin extends AsyncTask<Object, Void, String> {          private final static String TAG = "LoginActivity.EfetuaLogin";          @Override         protected void onPreExecute()         {             Log.d(TAG, "Executando onPreExecute de EfetuaLogin");         }           @SuppressWarnings("unchecked")         @Override         protected String doInBackground(Object... parametros) {             Log.d(TAG, "Executando doInBackground de EfetuaLogin");             Object[] params = parametros;             HttpClient httpClient = (HttpClient) params[0];             List<NameValuePair> listaParametros = (List<NameValuePair>) params[1];             String result = null;             try{             result = HttpProxy.httpPost(AnototudoMetadata.URL_AUTENTICACAO, httpClient, listaParametros);             }catch (IOException e) {                 Log.e(TAG, "IOException, Sem conectividade com o servidor do Anototudo! " + e.getMessage());                 e.printStackTrace();                 return result;             }             return result;         }          @Override         protected void onPostExecute(String result)         {             progressDialog.dismiss();         }      }  

3) When the button is pressed I than build the ProgressDialog anc call the AsyncTask I have created:

    OnClickListener loginListener = new OnClickListener() {       public void onClick(View v) {   //next line should start progress dialog in main thread ?????    progressDialog = ProgressDialog.show(LoginActivity.this, "Login in", "Wait a moment please", true, false);     //next couple of lines should do an ascyn call to server    EfetuaLogin efetuaLogin = new EfetuaLogin();    efetuaLogin.execute(params);    try {     //recover the server response and sets time out to be 25seconds     sResposta = efetuaLogin.get(25, TimeUnit.SECONDS); 

Well, this is it, I believe this was suppose to show a progress dialog while the AsyncTask would query the server in background, but what I get is NO progress bar until server response arrives and than for a fraction of time(less than 1 second) the progress shows and the next Activity is called.

As I mentioned I have re-checked this code and simply can't find where I got it wrong. Any suggestions?

Thank you in advance.

Hi, as suggested by Charlie Sheen(???) in the first answer for this thread I have tryied changing a bit of my code and now it is like(Unfortunatelly it is not working as expected so far):

OnClickListener loginListener = new OnClickListener() {         public void onClick(View v) {                 //async call????????         new EfetuaLogin().execute(params); ... 

And than do all the work to deal with response in the AsyncTask:

class EfetuaLogin extends AsyncTask<Object, Void, String> {          private final static String TAG = "LoginActivity.EfetuaLogin";          @Override         protected void onPreExecute()         {             super.onPreExecute();             Log.d(TAG, "Executando onPreExecute de EfetuaLogin");             //inicia diálogo de progresso, mostranto processamento com servidor.             progressDialog = ProgressDialog.show(LoginActivity.this, "Autenticando", "Contactando o servidor, por favor, aguarde alguns instantes.", true, false);         }           @SuppressWarnings("unchecked")         @Override         protected String doInBackground(Object... parametros) {             Log.d(TAG, "Executando doInBackground de EfetuaLogin");             Object[] params = parametros;             HttpClient httpClient = (HttpClient) params[0];             List<NameValuePair> listaParametros = (List<NameValuePair>) params[1];             String result = null;             try{             result = HttpProxy.httpPost(AnototudoMetadata.URL_AUTENTICACAO, httpClient, listaParametros);             }catch (IOException e) {                 Log.e(TAG, "IOException, Sem conectividade com o servidor do Anototudo! " + e.getMessage());                 e.printStackTrace();                 return result;             }             return result;         }          @Override         protected void onPostExecute(String result)         {             super.onPostExecute(result);              if (result == null || result.equals("")) {                 progressDialog.dismiss();                 Alerta                         .popupAlertaComBotaoOK(                                 "Dados incorretos",                                 "Os dados informados não foram encontrados no Sistema! Informe novamente ou cadastre-se antes pela internet.",                                 LoginActivity.this);                 return;             }              Log.d(TAG, "Login passou persistindo info de login local no device");             ContentValues contentValues = new ContentValues();             contentValues.put(AnototudoMetadata.LOGIN_EMAIL, sLogin);             contentValues.put(AnototudoMetadata.LOGIN_SENHA, sSenha);             contentValues.put(AnototudoMetadata.LOGIN_SENHA_GERADA, result);             LoginDB loginDB = new LoginDB();             loginDB.addLogin(LoginActivity.this, contentValues);             Log.d(TAG, "Persistiu info de login no device, redirecionando para menu principal do Anototudo");             Log.d(TAG, "O retorno da chamada foi ==>> " + result);             // tudo ok chama menu principal             Log.d(TAG, "Device foi corretametne autenticado, chamando tela do menu principal do Anototudo.");              String actionName = "br.com.anototudo.intent.action.MainMenuView";             Intent intent = new Intent(actionName);             LoginActivity.this.startActivity(intent);             progressDialog.dismiss();         }      }  

Complete OnClickListener:

OnClickListener loginListener = new OnClickListener() {     public void onClick(View v) {         Log.d(TAG, "Usuario logado, chamando menu principal");         TextView tLogin = (TextView) findViewById(R.id.loginText);         TextView tSenha = (TextView) findViewById(R.id.senhaText);         String sLogin = tLogin.getText().toString();         String sSenha = tSenha.getText().toString();          if (sLogin.equals("") | sSenha.equals("")) {             Alerta.popupAlertaComBotaoOK("Campos Obrigatórios",                     "Os campos Login e Senha são obrigatórios para autenticação do Anototudo.", LoginActivity.this);             return;         } else {             Pattern regEx = Pattern.compile(".+@.+\\.[a-z]+");             Matcher matcher = regEx.matcher(sLogin);             if (!matcher.matches()) {                 Alerta.popupAlertaComBotaoOK("Formato e-mail inválido", "O formato do campo e-mail está inválido",                         LoginActivity.this);                 return;             }         }           List<NameValuePair> listaParametros = new ArrayList<NameValuePair>();         listaParametros.add(new BasicNameValuePair("login", sLogin));         listaParametros.add(new BasicNameValuePair("senha", sSenha));          Log.d(TAG, "valores recuperados dos campos de login e senha: " + sLogin + " | " + sSenha);          // Reutiliza cliente HttpClient disponibilizado pela Aplicação.         AnototudoApp atapp = (AnototudoApp) LoginActivity.this.getApplication();         HttpClient httpClient = atapp.getHttpClient();          //prepara lista de parametros para fazer chamada asíncrona no servidor para autenticar.         Object[] params = new Object[2];         params[0] = httpClient;         params[1] = listaParametros;          //faz chamada assincrona         new EfetuaLogin().execute(params);     } }; 

Answer 1

Place your ProgressDialog in onPreExecute, sample code below:

private ProgressDialog pdia;  @Override protected void onPreExecute(){     super.onPreExecute();         pdia = new ProgressDialog(yourContext);         pdia.setMessage("Loading...");         pdia.show();     }  @Override protected void onPostExecute(String result){    super.onPostExecute(result);         pdia.dismiss(); } 

and in your onClickListener, just put this line inside:

new EfetuaLogin().execute(null, null , null);