Thread: Check if system tray already exists

Is there any way I can check if a system tray already exists as at the moment If I keep clicking the Jar file to create a system tray then multiple occurrences appear, which means multiple programs are run.

Another way I've used:
Check if certain file exists, if already created then can't use system tray, if file has not created then create and run system tray, when exiting system tray delete file.

--- Update ---

I have got it to partially work with server socket in that multiple instances of system tray class can't be invoked at the same time though for some reason it does not appear as an icon on the system tray even though it my be running in eclipse.

public class SystemTrayPostItNotes{
 
	public static void main(String[]args)throws Exception{
 
		try{
        final ServerSocket socket = new ServerSocket(5000);
		final Socket clientSocket = socket.accept();
 
 
	   PopupMenu popUp = new PopupMenu();
	   MenuItem exit = new MenuItem("Exit");
	   exit.addActionListener(new ActionListener(){
		   public void actionPerformed(ActionEvent event){
			   try {
				 clientSocket.close();
				 socket.close();
			   }catch (IOException e) {
				 System.out.println("Can't close");
			   }
			   System.exit(0);
		   }
 
	   });
	   popUp.add(exit);
       Image image = Toolkit.getDefaultToolkit().getImage("C:\\Users\\keepStriving\\Desktop\\GeoGebra_icon_edit.png");
       TrayIcon trayIcon = new TrayIcon(image, "Post It Notes Program", popUp);
       SystemTray.getSystemTray().add(trayIcon);
       trayIcon.addActionListener(new ActionListener(){
    	  public void actionPerformed(ActionEvent event){
    		  MainGuiNotes notes = new MainGuiNotes();
    	  }
       });
		}catch(Exception except){
			System.out.println("Already in use");
		}
	}
  }

final ServerSocket socket = new ServerSocket(5000);
final Socket clientSocket = socket.accept();

can you not put this at the end so it will set the tray up first as I think the program blocks when you issue socket.accept().

Put this at the end so it sets the tray up and then blocks.

Originally Posted by Norm

What happened when you created a test program that used the ServerSocket when you started the program for the second time?

The first system tray keeps running and I get an output that there is already one running so can't open the second, though get no icon appears.

--- Update ---

Originally Posted by mds1256

final ServerSocket socket = new ServerSocket(5000);
final Socket clientSocket = socket.accept();

can you not put this at the end so it will set the tray up first as I think the program blocks when you issue socket.accept().

Put this at the end so it sets the tray up and then blocks.

I tried it and it shows the icons and recognises when another system tray is already in use through message though also allows multiple icons to appear which is strange.

No, I'll stick with file method.

Oh I get you, my file method only works if the user gracefully exits. Is there some sort of method which I can force before the exit so I can delete the file once again upon a forceful exit by the user.

I've tried it though I get an illegal state exception though the program continues running, this is how I implemented it.

import java.awt.AWTException;
import java.awt.Image;
import java.awt.MenuItem;
import java.awt.PopupMenu;
import java.awt.SystemTray;
import java.awt.Toolkit;
import java.awt.TrayIcon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
import java.net.*;
 
public class SystemTrayPostItNotes{
 
	public static void main(String[]args)throws Exception{
 
	Runtime.getRuntime().addShutdownHook(new Thread(new Runnable(){	
		public void run(){
     final File file = new File("C:\\Users\\HASEEB\\Desktop\\On.txt");
       if(!file.exists()){
           try {
			file.createNewFile();
		} catch (IOException e) {
		}
 
	   PopupMenu popUp = new PopupMenu();
	   MenuItem exit = new MenuItem("Exit");
	   popUp.add(exit);
       Image image = Toolkit.getDefaultToolkit().getImage("C:\\Users\\HASEEB\\Desktop\\GeoGebra_icon_edit.png");
       TrayIcon trayIcon = new TrayIcon(image, "Post It Notes Program", popUp);
       try {
		SystemTray.getSystemTray().add(trayIcon);
	} catch (AWTException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
 
       trayIcon.addActionListener(new ActionListener(){
    	  public void actionPerformed(ActionEvent event){
    		  MainGuiNotes notes = new MainGuiNotes();
    	  }
       });
       exit.addActionListener(new ActionListener(){
		   public void actionPerformed(ActionEvent event){
			  file.delete();
			  /* try {
				 clientSocket.close();
				 socket.close();
			   }catch (IOException e) {
				 System.out.println("Can't close");
			   }*/
			   System.exit(0);
		   }
 
	   });
       //System.out.println("zzzzzzzzzz");
		}else{
 
		}
    // }else{
    	// System.out.println("Already open");
     //}
		}
	 }));
	}
  }

I have moved what you mentioned from run method though file does not delete upon forceful exit of program though recognises to shut program if another program is already running. Also icon still not appearing.Thank you for your help so far.

public static void main(String[]args)throws Exception{
		final File file = new File("C:\\Users\\HASEEB\\Desktop\\On.txt");
		final PopupMenu popUp = new PopupMenu();
		   final MenuItem exit = new MenuItem("Exit");
		   popUp.add(exit);
		   Image image = Toolkit.getDefaultToolkit().getImage("C:\\Users\\HASEEB\\Desktop\\GeoGebra_icon_edit.png");
	       final TrayIcon trayIcon = new TrayIcon(image, "Post It Notes Program", popUp);
 
	Runtime.getRuntime().addShutdownHook(new Thread(new Runnable(){	
		public void run(){
       if(!file.exists()){
           try {
			file.createNewFile();
		} catch (IOException e) {
		}
 
	  /* */
       try {
		SystemTray.getSystemTray().add(trayIcon);
	} catch (AWTException e) {
	}
 
       trayIcon.addActionListener(new ActionListener(){
    	  public void actionPerformed(ActionEvent event){
    		  MainGuiNotes notes = new MainGuiNotes();
    	  }
       });
       exit.addActionListener(new ActionListener(){
		   public void actionPerformed(ActionEvent event){
			  file.delete();
			   System.exit(0);
		   }
 
	   });
		}else{
 
		}
		}
	 }));
	}
  }

I still can't get the display, though also get mixed results with the file still not being deleted. I have changed the code from my last attempt. The program does not stop and keeps running.

public class SystemTrayPostItNotes{
 
	final static File file = new File("C:\\Users\\HASEEB\\Desktop\\On.txt");
	final static PopupMenu popUp = new PopupMenu();
	final static MenuItem exit = new MenuItem("Exit");
	static TrayIcon trayIcon = null;
 
	public static void main(String[]args)throws Exception{
		popUp.add(exit);
		Image image = Toolkit.getDefaultToolkit().getImage("C:\\Users\\HASEEB\\Desktop\\GeoGebra_icon_edit.png");
	    trayIcon = new TrayIcon(image, "Post It Notes Program", popUp);
		SystemTrayPostItNotes tray = new SystemTrayPostItNotes();
		tray.addShutdownHook(file);
		if(file.exists()){
		   file.delete();
	       System.out.println("File deleted");
		}else{
			System.out.println("file does not exist");
		}
	}
 
	public static void addShutdownHook(final File file){
		Runtime.getRuntime().addShutdownHook(new Thread(){
          public void run(){
 
       if(!file.exists()){
           try {
			file.createNewFile();
		} catch (IOException e) {
 
		}
 
		  try {
			SystemTray.getSystemTray().add(trayIcon);
		} catch (AWTException e) {
 
		}
 
 
          trayIcon.addActionListener(new ActionListener(){
    	   public void actionPerformed(ActionEvent event){
    		  MainGuiNotes notes = new MainGuiNotes();
    	  }
          });
          exit.addActionListener(new ActionListener(){
		   public void actionPerformed(ActionEvent event){
			   System.exit(0);
		   }
		   });
		}else{
			System.out.println("File already exists therefore program already running");
		}
       }
    });
	}
	}

Turn out shutdown hook does not work for forceful exits, though I managed to get it to work for graceful exits ad understand it now.
I have managed to do the task with sockets here is the code, thanks guys.

public class SystemTrayPostItNotes extends Thread{
 
	static File file = new File("C:\\Users\\HASEEB\\Desktop\\On.txt");
 
 
	public static void main(String[]args)throws Exception{
	   try{
		   connectSocket();
		   sysTrayCreator();
	   }catch(Exception except){
		   System.out.println("Sorry busy");
		   System.exit(0);
	   }
	}
 
	public static void sysTrayCreator(){
		try{
	    PopupMenu popUp = new PopupMenu();
	    MenuItem exit = new MenuItem("Exit");
		popUp.add(exit);
	    Image image = Toolkit.getDefaultToolkit().getImage("C:\\Users\\HASEEB\\Desktop\\GeoGebra_icon_edit.png");
	    TrayIcon trayIcon = new TrayIcon(image, "Post It Notes Program", popUp);
		SystemTrayPostItNotes tray = new SystemTrayPostItNotes();
 
		SystemTray.getSystemTray().add(trayIcon);
 
		     trayIcon.addActionListener(new ActionListener(){
	    	   public void actionPerformed(ActionEvent event){
	    		  MainGuiNotes notes = new MainGuiNotes();
	    	  }
	          });
	          exit.addActionListener(new ActionListener(){
			   public void actionPerformed(ActionEvent event){
				   System.exit(0);
			   }
			   });
		}catch(Exception except){
			System.out.println("Sorry currently busy");
		}
	}
 
	public static void connectSocket()throws Exception{
		ServerSocket serverSock = new ServerSocket(9090);
		Socket socket = serverSock.accept();
	}
 
}

--- Update ---

I got a small error due to synchronization though amended this with Thread.sleep(1000), though for some reason this causes two system tray icons upon first time running but only for a second after which only one is left. My final code.

public class SystemTrayPostItNotes implements Runnable{
 
	static File file = new File("C:\\Users\\HASEEB\\Desktop\\On.txt");
 
 
	public static void main(String[]args)throws Exception{
	   (new Thread(new SystemTrayPostItNotes())).start();
	}
 
	public void run(){
		try{
			sysTrayCreator();
			connectSocket();
		}catch(Exception except){
			System.out.println("Sorry busy");
			System.exit(0);
		}
 
	}
 
	public static void sysTrayCreator()throws Exception{
		Thread.sleep(1000);
		try{
	    PopupMenu popUp = new PopupMenu();
	    MenuItem exit = new MenuItem("Exit");
		popUp.add(exit);
	    Image image = Toolkit.getDefaultToolkit().getImage("C:\\Users\\HASEEB\\Desktop\\GeoGebra_icon_edit.png");
	    TrayIcon trayIcon = new TrayIcon(image, "Post It Notes Program", popUp);
		SystemTrayPostItNotes tray = new SystemTrayPostItNotes();
		SystemTray.getSystemTray().add(trayIcon);
 
		     trayIcon.addActionListener(new ActionListener(){
	    	   public void actionPerformed(ActionEvent event){
	    		  MainGuiNotes notes = new MainGuiNotes();
	    	  }
	          });
	          exit.addActionListener(new ActionListener(){
			   public void actionPerformed(ActionEvent event){
				   System.exit(0);
			   }
			   });
		}catch(Exception except){
			System.out.println("Sorry currently busy");
		}
	}
 
	public static void connectSocket()throws Exception{
		ServerSocket serverSock = new ServerSocket(9090);
		Socket socket = serverSock.accept();
	}
 
}

Which is why I used multithreading. It seems to work or am I going wrong somewhere again?

In second code:
The new thread and run method is meant to allow multithreading which it does as I can do sysTrayCreator() and connectSocket() though I slow down sysTrayCreator() so exception can be thrown if not accepting. It does allow multithreading as I can see icon being created alongside socket connecting.

I'm still not sure what you are trying to say?