How to check if there was an error in the POST

Question

I need to check if there was any error in the reply of onPostExecute or gave time out on the server, because sometimes it gives some error in the process and this method does not even start, as I could do such check?

I call him that:

 ConnectivityManager connMgr = (ConnectivityManager)
                    getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

            if (networkInfo != null && networkInfo.isConnected()) {
                url = "https://...";

                parametros = "paramentro=" + string;

                new minhaclasse.SolicitaDados().execute(url);

            } else {
                Toast.makeText(getApplicationContext(), "Erro, tente novamente!", Toast.LENGTH_LONG).show();
            }

And then he executes:

private class SolicitaDados extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {

        return Conexao.postDados(urls[0], parametros);
    }

    @Override
    protected void onPostExecute(String resultado) {

        if(resultado != null && resultado != "") {

        }
    }
}

Connection class:

  public class Conexao {

  public static String postDados(String urlUsuario, String parametrosUsuario) {
    URL url;
    HttpURLConnection connection = null;

    try {

        url = new URL(urlUsuario);
        connection = (HttpURLConnection) url.openConnection();

        connection.setRequestMethod("POST");

        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");

        connection.setRequestProperty("Content-Lenght", "" + Integer.toString(parametrosUsuario.getBytes().length));

        connection.setRequestProperty("Content-Language", "pt-BR");

        //connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");

        connection.setUseCaches(false);
        connection.setDoInput(true);
        connection.setDoOutput(true);

        OutputStreamWriter outPutStream = new 
        OutputStreamWriter(connection.getOutputStream(), "utf-8");
        outPutStream.write(parametrosUsuario);
        outPutStream.flush();
        outPutStream.close();

        InputStream inputStream = connection.getInputStream();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));

        String linha;
        StringBuffer resposta = new StringBuffer();

        while((linha = bufferedReader.readLine()) != null) {
         resposta.append(linha);
            resposta.append('\r');
        }

        bufferedReader.close();

        return resposta.toString();

    } catch (Exception erro) {

        return  null;
    } finally {

        if(connection != null) {
            connection.disconnect();
        }
    }
}
}

Answer 1

whereas his AsyncTask is returning a value:

// Instancia o obj
SolicitaDados obj = new SolicitaDados();
// Executa a classe `AssyncTask`
obj.execute();
// Puxa o retorno (se for int)
int retorno = obj.get();

The get() will wait for the end of the doInBackground, and return your onPostExecute.

Asynctask - final Result

Complementing:

The code is correct, only remaining to treat a timeout HttpURLConnection not to run without prediction for whatever reason.

Example:

HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); 
httpURLConnection.setRequestMethod("POST"); 
httpURLConnection.setReadTimeout(3000); 
httpURLConnection.setConnectTimeout(3000); 
httpURLConnection.setDoInput(true); 
httpURLConnection.setDoOutput(true); 
httpURLConnection.connect();