package com.example.udp_client;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.RelativeLayout;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

/* In manifests file, add 
    <uses-permission android:name="android.permission.INTERNET" /> 
   Run sending UDP data by AsyncTask or Thread */

public class MainActivity extends Activity
{
    private DatagramSocket ds=null;
    private InetAddress addr;
    private int port;
    byte[] bytes;

    @Override protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      RelativeLayout.LayoutParams lp=new RelativeLayout.LayoutParams(
          RelativeLayout.LayoutParams.MATCH_PARENT,RelativeLayout.LayoutParams.MATCH_PARENT);
      RelativeLayout layout = new RelativeLayout(this);
      setContentView(layout, lp);

      // prepare data to be sent
      try {
        JSONObject obj = new JSONObject();
        obj.put("vid", 1);
        obj.put("udid", "112233");
        obj.put("lat", 1.345f);
        obj.put("lng", 103.567);
        String s = obj.toString();
        bytes = s.getBytes("UTF-8");
      }
      catch (JSONException e){System.out.println(e.toString());}
      catch(IOException e) {System.out.println(e.toString());}

      //* create UDP Socket
      try {
        addr = InetAddress.getByName("192.168.1.41");
        port = 16099;
        ds = new DatagramSocket();
      }
      catch(IOException e) {System.out.println(e.toString());}

      //* Sending UDP data by AsyncTask in a thread
      AsyncTask.execute(new Runnable(){
        @Override public void run(){
          try {
            DatagramPacket packet=new DatagramPacket(bytes,bytes.length,addr,port);
            ds.send(packet);
            Log.d("ExampleOut","sent 1");
          }
          catch(IOException e) {System.out.println(e.toString());}
        }
      });

      //* Or Sending UDP data by Thread
      Thread thread = new Thread(new Runnable(){
        @Override public void run() {
          try {
            DatagramPacket packet=new DatagramPacket(bytes,bytes.length,addr,port);
            ds.send(packet);
            Log.d("ExampleOut","sent 2");
          }
          catch (IOException e) {System.out.println(e.toString());}
        }
      });
      thread.start();
    }
}