DONE

package testing.gps_location;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.SystemClock;
import android.provider.Settings;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.Socket;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.nio.channels.DatagramChannel;
import java.util.Date;
import java.util.Enumeration;

public class MainActivity extends AppCompatActivity {

    private Button b;
    private TextView t;
    private LocationManager locationManager;
    private LocationListener listener;
    TextView textResponse = null;
    String phoneID ="";

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        t = (TextView) findViewById(R.id.textView);
        b = (Button) findViewById(R.id.button);
        phoneID = Settings.Secure.getString(getContentResolver(), Settings.Secure.ANDROID_ID);
        textResponse = t;
        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);


        listener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                //t.append("\n " + location.getLongitude() + " " + location.getLatitude());
                MyUDP myUDP = new MyUDP("192.168.56.1",10000,location.getLongitude(),location.getLatitude() );
                myUDP.execute();

            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {

            }

            @Override
            public void onProviderEnabled(String s) {

            }

            @Override
            public void onProviderDisabled(String s) {

                Intent i = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                startActivity(i);
            }
        };

        configure_button();

        MyTCP myClientTask = new MyTCP("192.168.56.1", 5000);
        myClientTask.execute();


    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 10:
                configure_button();
                break;
            default:
                break;
        }
    }

    void configure_button() {
        // first check for permissions
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.INTERNET}
                        , 10);
            }
            return;
        }
        // this code won't execute IF permissions are not allowed, because in the line above there is return statement.
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //noinspection MissingPermission
                locationManager.requestLocationUpdates("gps", 5000, 0, listener);
            }
        });
    }

    public class MyTCP extends AsyncTask<Void, String, Void> {

        String dstAddress;
        int dstPort;
        String response = "";

        MyTCP(String addr, int port) {
            dstAddress = addr;
            dstPort = port;
        }

        @Override
        protected Void doInBackground(Void... arg0) {

            Socket socket = null;
            DataOutputStream dataOutputStream = null;
            //DataInputStream dataInputStream = null;
            //while(true) {
                try {
                    socket = new Socket(dstAddress, dstPort);
                    dataOutputStream = new DataOutputStream(
                            socket.getOutputStream());
                    dataOutputStream.writeUTF(phoneID);
                    //dataInputStream = new DataInputStream(socket.getInputStream());
                    BufferedReader buff = new BufferedReader(new
                            InputStreamReader(socket.getInputStream()));
                    String inputLine= buff.readLine();
                    while(inputLine != null) {
                        //khi gọi hàm này thì onProgressUpdate sẽ thực thi
                        publishProgress(inputLine);
                        inputLine= buff.readLine();

                    }
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                    response = "UnknownHostException: " + e.toString();
                } catch (IOException e) {
                    e.printStackTrace();
                    response = "IOException: " + e.toString();
                } finally {
                    if (socket != null) {
                        try {
                            socket.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (dataOutputStream != null) {
                        try {
                            dataOutputStream.close();
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                    }

                }
               // SystemClock.sleep(5000);
            //}

            return  null;
        }
        @Override
        protected void onProgressUpdate(String... values) {
            // TODO Auto-generated method stub
            super.onProgressUpdate(values);
            textResponse.append("\n" + values[0]);
            if(response != "") {
                textResponse.setText(response);
                response ="";
            }
        }
        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            //textResponse.append("\n" + response);
        }

    }

    public class MyUDP extends AsyncTask<Void, Void, Void> {

        String dstAddress;
        int dstPort;
        String response = "";
        String message = "This is my message";

        MyUDP(String addr, int port,double x, double y) {
            dstAddress = addr;
            dstPort = port;
            java.util.Date date=new Date();
            message =  phoneID +"@" + String.format("%.4f", x) + "@" +String.format("%.4f", y) + "@" + date.getTime();
        }

        @Override
        protected Void doInBackground(Void... arg0) {

            try {
                //Preparing the socket
                InetAddress serverAddr = InetAddress.getByName(dstAddress);
                DatagramSocket socket = new DatagramSocket();
                //Preparing the packet
                byte[] buf = message.getBytes();
                DatagramPacket packet = new DatagramPacket(buf, buf.length, serverAddr, dstPort);


                socket.send(packet);
            } catch (Exception e) {
                response = e.toString();
            }

            return  null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            textResponse.append("\n" + response);
        }

    }

}