Android - 在 AsyncTask 执行时显示进度对话框

Question

I have the following class, which calls a web service that sends an email, which can take up to 5 seconds, depending on the connection. The idea is to show a message to the user while the mail is being sent, so that it is on hold and can not perform any action

This is my class:

private class TareaEnviarMail extends AsyncTask<String, Void, String>
    {
        ProgressDialog.Builder b;

        @Override
        protected String doInBackground(String... params)
        {
            try {

                URL url = new URL("https://example.sendmail.com");
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setRequestMethod("POST");

                InputStream in = new java.io.BufferedInputStream(conn.getInputStream());
                String response = org.apache.commons.io.IOUtils.toString(in, "UTF-8");

            }
            catch(Exception ex)
            {
                Log.e("Error",ex.toString());
            }

            return null;

        }

        @Override
        protected void onPostExecute(String result)
        {
            //HERE, I WANT TO DISMISS THE DIALOG!!! LIKE b.dismiss(); ¿?
            Intent intent = new Intent(getApplicationContext(), ActividadPrincipal.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
        }

        @Override
        protected void onPreExecute()
        {
            b = new  ProgressDialog.Builder(ActividadNuevoTurnoSeleccionar.this);
            b.setTitle("Enviando correo. Revise su casilla.");
            b.setMessage("Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.");
            b.create().show();
            //ProgressDialog.show(ActividadNuevoTurnoSeleccionar.this,"Enviando correo. Revise su casilla.", "Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.");
        }

        @Override
        protected void onProgressUpdate(Void... values) {}
    }

The problem is that now I don't know how to close the dialog in onpostexecute method, when the background task is over. Since I don't have the dialog, but the builder. Could you help me? Thank you

Answer 1

Change ProgressDialog.Builder b; to dialog, like ProgressDialog dialog; , since you need the reference of the dialog and not it's builder, on onPreExecute you can create the builder and assign the dialog it builds to the dialog declared before.

@Override
        protected void onPreExecute()
        {
            ProgressDialog.Builder b = new  ProgressDialog.Builder(ActividadNuevoTurnoSeleccionar.this);
            b.setTitle("Enviando correo. Revise su casilla.");
            b.setMessage("Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.");
            dialog = b.create();
            b.show();
            //ProgressDialog.show(ActividadNuevoTurnoSeleccionar.this,"Enviando correo. Revise su casilla.", "Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.");
        }

Then dismiss the dialog as usual in onPostExecute();

Answer 2

    private class TareaEnviarMail extends AsyncTask<String, Void, String> {
    ProgressDialog progressDialog;

    @Override
    protected String doInBackground(String... params) {
        try {

            URL url = new URL("https://example.sendmail.com");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");

            InputStream in = new java.io.BufferedInputStream(conn.getInputStream());
            String response = org.apache.commons.io.IOUtils.toString(in, "UTF-8");

        } catch (Exception ex) {
            Log.e("Error", ex.toString());
        }

        return null;

    }

    @Override
    protected void onPostExecute(String result) {
        //HERE, I WANT TO DISMISS THE DIALOG!!! LIKE b.dismiss(); ¿?

        if(progressDialog!=null && progressDialog.isShowing())
            progressDialog.dismiss();
        Intent intent = new Intent(getApplicationContext(), ActividadPrincipal.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(intent);
    }

    @Override
    protected void onPreExecute() {
        progressDialog = new ProgressDialog(ActividadNuevoTurnoSeleccionar.this);
        progressDialog.setMessage("Please wait...");
        progressDialog.setCancelable(false);
        progressDialog.show();


    }

    @Override
    protected void onProgressUpdate(Void... values) {
    }
}

Answer 3

Create an object of progress dialog and replace onPostExecute and onPreExecute with below code

ProgressDialog dialog;

    @Override
    protected void onPostExecute(String result)
    {
        dismiss.show();
        //HERE, I WANT TO DISMISS THE DIALOG!!! LIKE b.dismiss(); ¿?
        Intent intent = new Intent(getApplicationContext(), ActividadPrincipal.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(intent);
    }

    @Override
    protected void onPreExecute()
    {
       dialog= new  ProgressDialog.Builder(ActividadNuevoTurnoSeleccionar.this)
        .setTitle("Enviando correo. Revise su casilla.")
        .setMessage("Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.")
        .create();
        dialog.show();
        //ProgressDialog.show(ActividadNuevoTurnoSeleccionar.this,"Enviando correo. Revise su casilla.", "Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.");
    }

Answer 4

Another solution would be not using a builder.

ProgressDialog b;

and on preExecute

@Override
    protected void onPreExecute()
    {
        b = new  ProgressDialog(ActividadNuevoTurnoSeleccionar.this);
        b.setTitle("Enviando correo. Revise su casilla.");
        b.setMessage("Por favor, espere mientras registramos el turno y le enviamos la confirmación a su casilla.");
        b.create();
        b.show();
    }

Then again, just dismiss it as usual in postExecute.