Priority in progress

Question

It is possible to prioritize a progressdialog before a Thread? In my app, after clicking a button, I need to freeze a progressdialog for 2 seconds. After that, generate a query to my webservice, and as soon as return the data, they are presented in a alertdialog,that after opened, makes the progressdialog receive the dismiss() to close it. However, even instantiating a new Thread and setting the sleep() or wait(), the process just freezes the Thread for whole and does not present the progressdialog. On the screen, first the Alert is generated and the Progress is in the background until the Alert is closed.

Is there a possible way to generate Progress first with 2 seconds of Freeze and then the Alert dialog? Follows excerpt from the code.

    final EditText Nome = (EditText) findViewById(R.id.cmdDigDe);
    Button btnConDeE = (Button) findViewById(R.id.btnConDe);
    btnConDeE.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {

            ProgressDialog progressDialog = new ProgressDialog(DemE.this);
            progressDialog.setTitle("Listando medicamentos");
            progressDialog.setMessage("Buscando...");
            progressDialog.show();

                String nomeProduto = Nome.getText().toString();
                String laboratorio = null;
                String aliquota = "17";

                if (android.os.Build.VERSION.SDK_INT > 9) {
                    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
                    StrictMode.setThreadPolicy(policy);
                }

                if (nomeProduto == "") {
                    Toast.makeText(DemE.this, "Por favor digite o nome do medicamento", Toast.LENGTH_LONG).show();
                } else

                    try {
                        URL url = new URL("http");
                        URLConnection con = url.openConnection();
                        con.setDoOutput(true);
                        OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());

                        writer.write("nome=" + nomeProduto + "&aliquota=" + aliquota + (laboratorio != null ? "&laboratorio=" + laboratorio : ""));
                        writer.flush();

                        BufferedReader reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
                        String result = "";
                        String line;


                        while ((line = reader.readLine()) != null) {

                            result += line;

                            TextView tv = (TextView) findViewById(R.id.tv);
                            tv.setText(Html.fromHtml(result));

                            final String text = tv.getText().toString();


                            AlertDialog alertDialog = new AlertDialog.Builder(context).create();
                            alertDialog.setTitle("Medicamentos:");
                            alertDialog.setMessage(text);
                            alertDialog.setButton("Voltar", new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    dialog.cancel();
                                }
                            });

                            progressDialog.dismiss();
                            alertDialog.show();


                        }

                        writer.close();
                        reader.close();

                    }

Answer 1

Diego, I see some strange things in your code, for example, you’re calling the method AlertDialog alertDialog = new AlertDialog.Builder(context).create(); inside the loop (while). Second, you are running a process that may take time inside the main thread.

You could use a AsyncTask, then in the method onPreExecute, you start your ProgressDialog, in the method doInBackground you make your Http call and method onPostExecute, you finalize your ProgressDialog and displays his AlertDialog.

Read more about Asynctask

Answer 2

It is right to do this using an Asynctask

-Your Victoria would look like this:

public class DemE extends Activity implements View.OnClickListener
{
    //Suponho que seja aqui aonde você roda o metodo
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        findViewById(R.id.btnConDe).setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        String nomeProduto =  findViewById(R.id.cmdDigDe).getText().toString();
        String laboratorio = null;
        String aliquota = "17";


        if (nomeProduto == "") 
            Toast.makeText(DemE.this, "Por favor digite o nome do medicamento", Toast.LENGTH_LONG).show();
        else
            new BuscaMedicamentosAsync(this).execute(
                new StringBuilder("nome=")
                        .append(nomeProduto)
                        .append("&aliquota=")
                        .append(aliquota)
                        .append("&laboratorio=")
                        .append(laboratorio == null? "" : laboratorio));
    }
}

-And the processing is on account of async:

public final class BuscaMedicamentosAsync extends AsyncTask<CharSequence, Integer, CharSequence>
{
    private final AlertDialog alertDialog;
    private final ProgressDialog progressDialog;

    public BuscaMedicamentosAsync(Context contexto)
    {
        this.alertDialog = new AlertDialog.Builder(contexto).create();
        alertDialog.setTitle("Medicamentos:");
        alertDialog.setButton(0, "Voltar", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                dialog.cancel();
            }
        });

        progressDialog = new ProgressDialog(contexto);
        progressDialog.setTitle("Listando medicamentos");
        progressDialog.setMessage("Buscando...");
        progressDialog.show();
        progressDialog.setCancelable(false); //Impedir que o usuario feche o dialogo
    }

    @Override
    protected CharSequence doInBackground(CharSequence... parametros)
    {
        StringBuilder result = new StringBuilder();
        try {
            URL url = new URL("http");
            URLConnection con = url.openConnection();
            con.setDoOutput(true);
            OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());

            writer.write(parametros[0].toString());
            writer.flush();

            BufferedReader reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String line;


            while ((line = reader.readLine()) != null) {

                result.append(line);
            }

            writer.close();
            reader.close();

        } catch (Exception e) {
            //Trata a exceção
        }

        return Html.fromHtml(result.toString()).toString();
    }

    @Override
    protected void onPostExecute(CharSequence text) {
        super.onPostExecute(text);

        progressDialog.dismiss();

        alertDialog.setMessage(text);
        alertDialog.show();
    }
}

Recommended reading

• Asynctask