Progressbar with Async Task while trying to connect to server

Issue

I want to show Progress Dialog when background task is executed by doInbackground Method of AsyncTask Class, But the problem is when my server is off (Wamp server turns off) it doesnot shows Progress Dialog when trying to get connected with the server. Please Help in this regard.

Main Class:

import android.app.AlertDialog;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Spinner;
import android.widget.Toast;
import java.util.Calendar;
import java.util.Date;
import java.text.SimpleDateFormat;
import java.util.concurrent.ExecutionException;

public class MainActivity extends AppCompatActivity{

    Button btnSubmitOrder;
    EditText edDealerID;
    EditText edProductID;
    EditText edQuantity;
    String stDealerID;
    String stProductID;
    String stQuantity;
    String stUnit;
    String stDate;
    String stTime;
    String stStatus;
    ProgressBar edProgress;

    Date currentDate = Calendar.getInstance().getTime();

    DatabaseSQLite objDatabaseSqlite;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        Date objDate = Calendar.getInstance().getTime();
        SimpleDateFormat df = new SimpleDateFormat("dd/MMM/yyyy");
        stDate = df.format(objDate);

        SimpleDateFormat sdf = new SimpleDateFormat("hh:mm a");
        stTime = sdf.format(objDate);

        final Spinner dropdown = findViewById(R.id.edit_unit);
        String[] items = new String[]{"Box", "Packets"};
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item, items);
        dropdown.setAdapter(adapter);

        objDatabaseSqlite = new DatabaseSQLite(this);

        btnSubmitOrder = findViewById(R.id.btn_submitorder);
        edDealerID = findViewById(R.id.edit_dealerid);
        edProductID = findViewById(R.id.edit_productid);
        edQuantity = findViewById(R.id.edit_quantity);
        edProgress = findViewById(R.id.ed_progress);
        btnSubmitOrder.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stDealerID = edDealerID.getText().toString();
                stProductID = edProductID.getText().toString();
                stQuantity = edQuantity.getText().toString();
                stUnit = dropdown.getSelectedItem().toString();
                stStatus = "Pending";
                BackgroundTask objBackground = new BackgroundTask(MainActivity.this);
                try {
                    String response = objBackground.execute(stDealerID, stProductID, stQuantity, stUnit, stDate, stTime, stStatus).get();
                } catch (ExecutionException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
    }

}

BackgroundTask Class:

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

/**
 * Created by Saffi on 3/17/2016.
 */
public class BackgroundTask extends AsyncTask<String,Void,String> {

    private String response = "";
    private ProgressDialog dialog;
    Context ctx;

    BackgroundTask(Context ctx)
    {
        this.ctx = ctx;
    }

    @Override
    protected void onPreExecute() {
        dialog = new ProgressDialog(ctx);
        dialog.setMessage("Progress start");
        dialog.show();
    }

    protected String doInBackground(String... params) {
        String sendInvoice = "http://10.0.2.2/YounasTraders/SendInvoice.php";
        String dealerId = params[0];
        String productId = params[1];
        String quantity = params[2];
        String unit = params[3];
        String date = params[4];
        String time = params[5];
        String status = params[6];
        try {
            URL objurl = new URL(sendInvoice);
            HttpURLConnection objhttpurlconnection = (HttpURLConnection) objurl.openConnection();
            objhttpurlconnection.setRequestMethod("POST");
            objhttpurlconnection.setDoOutput(true);
            objhttpurlconnection.setDoInput(true);
            OutputStream objos = objhttpurlconnection.getOutputStream();
            BufferedWriter objbuffwrite = new BufferedWriter(new OutputStreamWriter(objos, "UTF-8"));

            String data = URLEncoder.encode("dealer_id", "UTF-8") +"="+URLEncoder.encode(dealerId, "UTF-8")+"&"+
                    URLEncoder.encode("product_id", "UTF-8")+"="+URLEncoder.encode(productId, "UTF-8")+"&"+
                    URLEncoder.encode("quantity", "UTF-8")+"="+URLEncoder.encode(quantity, "UTF-8")+"&"+
                    URLEncoder.encode("unit", "UTF-8")+"="+URLEncoder.encode(unit, "UTF-8")+"&"+
                    URLEncoder.encode("date", "UTF-8")+"="+URLEncoder.encode(date, "UTF-8")+"&"+
                    URLEncoder.encode("time", "UTF-8")+"="+URLEncoder.encode(time, "UTF-8")+"&"+
                    URLEncoder.encode("status", "UTF-8")+"="+URLEncoder.encode(status, "UTF-8");
            objbuffwrite.write(data);
            objbuffwrite.flush();
            objbuffwrite.close();
            objos.close();

            InputStream objis = objhttpurlconnection.getInputStream();
            objis.close();
            objhttpurlconnection.disconnect();

            response = "Order Sent Successfully";

            return response;

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        response = "Order Not Sent Successfully";
        return response;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
        dialog.show();
    }

    @Override
    protected void onPostExecute(String value) {
        dialog.dismiss();
    }
}

Solution

The problem is you are executing a task on main thread using .get method

The first change your AsyncTask task include this callback interface to call it after finishing your HTTP request

public class BackgroundTask extends AsyncTask {

    private CallBack callBack;

    public CallBack getCallBack() {
        return callBack;
    }

    public void setCallBack(CallBack callBack) {
        this.callBack = callBack;
    }

    private String response = "";
    private ProgressDialog dialog;
    Context ctx;

    BackgroundTask(Context ctx)
    {
        this.ctx = ctx;
    }

    @Override
    protected void onPreExecute() {
        dialog = new ProgressDialog(ctx);
        dialog.setMessage("Progress start");
        dialog.show();
    }

    protected String doInBackground(String... params) {
        String sendInvoice = "http://10.0.2.2/YounasTraders/SendInvoice.php";
        String dealerId = params[0];
        String productId = params[1];
        String quantity = params[2];
        String unit = params[3];
        String date = params[4];
        String time = params[5];
        String status = params[6];
        try {
            URL objurl = new URL(sendInvoice);
            HttpURLConnection objhttpurlconnection = (HttpURLConnection) objurl.openConnection();
            objhttpurlconnection.setRequestMethod("POST");
            objhttpurlconnection.setDoOutput(true);
            objhttpurlconnection.setDoInput(true);
            OutputStream objos = objhttpurlconnection.getOutputStream();
            BufferedWriter objbuffwrite = new BufferedWriter(new OutputStreamWriter(objos, "UTF-8"));

            String data = URLEncoder.encode("dealer_id", "UTF-8") +"="+URLEncoder.encode(dealerId, "UTF-8")+"&"+
                    URLEncoder.encode("product_id", "UTF-8")+"="+URLEncoder.encode(productId, "UTF-8")+"&"+
                    URLEncoder.encode("quantity", "UTF-8")+"="+URLEncoder.encode(quantity, "UTF-8")+"&"+
                    URLEncoder.encode("unit", "UTF-8")+"="+URLEncoder.encode(unit, "UTF-8")+"&"+
                    URLEncoder.encode("date", "UTF-8")+"="+URLEncoder.encode(date, "UTF-8")+"&"+
                    URLEncoder.encode("time", "UTF-8")+"="+URLEncoder.encode(time, "UTF-8")+"&"+
                    URLEncoder.encode("status", "UTF-8")+"="+URLEncoder.encode(status, "UTF-8");
            objbuffwrite.write(data);
            objbuffwrite.flush();
            objbuffwrite.close();
            objos.close();

            InputStream objis = objhttpurlconnection.getInputStream();
            objis.close();
            objhttpurlconnection.disconnect();

            response = "Order Sent Successfully";

            return response;

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        response = "Order Not Sent Successfully";
        return response;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
        dialog.show();
    }

    @Override
    protected void onPostExecute(String value) {
        dialog.dismiss();
        if(callBack != null)
            callBack.onResult(value);

    }

    public interface CallBack{
        void onResult(String value);
    }
}

Second change execution of your async task, get result on callback

  BackgroundTask objBackground = new BackgroundTask(MainActivity.this);
        objBackground.setCallBack(new BackgroundTask.CallBack() {
            @Override
            public void onResult(String value) {
                //get here your response
            }
        });
        objBackground.execute(stDealerID, stProductID, stQuantity, stUnit, stDate, stTime, stStatus);

Answered By - Anderson Soares