Java中的计时器与线程？

Question

I am using the code below to open a frame-1 every x time but when i go to an other frame and back the timer reset itself causing a second frame-1 to show up which is problematic since I only need 1 at a time tried to use isvisbile() but did not work also.

Here is the code:

 int timerTimeInMilliSeconds2 = 30000;
    javax.swing.Timer timer2 = new javax.swing.Timer(timerTimeInMilliSeconds2, new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            Pop p=new Pop();
            p.setVisible(true);
            new Thread(){
                  @Override
                  public void run() {
                       try {
                              Thread.sleep(5000); // time after which pop up will be disappeared.
                              p.dispose();
                       } catch (InterruptedException e) {
                              e.printStackTrace();
                       }
                  };
            }.start();

        }
    });
    timer2.start();

Answer 1

Instead of having the Pop p object as a local variable inside your method having it as a member of your class. When actionPerformed triggers check whether it is null (a better name that p would be a good idea too) and only create the window if it is.

Rather than creating a thread to dispose the window after 5 seconds you should use another Timer anyway.

Answer 2

Your question is little bit uncleared. As what I can understood, you need to create Pop p as a member variable of your defined class instead of local variable of method actionPerformed so that you can check before triggering it weather the object is null or not.