Programming Forums > Application Development > Java

namsu · Apr 2nd, 2008, 9:12 AM

I am having a problem. If I have a JFrame open in a class and it performing and processing, when I close it, it still performs the work, which is good because this is what I want it to do. How do I actually return to that instance of the running program, if I go back to the main menu and click the button to load it up again, it makes a brand new instance. I need to return to the already running one.

Code for the back button

MainMenu m = new MainMenu();
m.setVisible(true);
dispose();

Code for loading up JFRAME Again from Main Menu

SandHopper sHopper = new SandHopper();
dispose();
sHopper.setVisible(true);

If someone can help me out here it would be great. Thank you.

Jimbo · Apr 2nd, 2008, 10:17 AM

You'll want a slightly different design where you keep a SandHopper object and instead of creating a new one each time you set it visible again. You can wrap this into a static method similar to this:

(Toggle Plain Text)

class SandHopper {
  private static SandHopper onlySandHopper;
  public static SandHopper GetSandHopper() {
    if(onlySandHopper == null) {
      onlySandHopper = new SandHopper();
    }
    return onlySandHopper;
  }

  // .. the rest of your class...
}

With this, you might want to make your constructors private, so that only GetSandHopper() can create one. The benefit to this: you reuse the same one all the time. The drawback: you can only have 1 SandHopper (if you want more than one, you can leave the constructors public, but anybody who calls GetSandHopper() will always use the same one).

Apr 2nd, 2008, 9:12 AM	#1
namsu Newbie Join Date: Jan 2008 Posts: 15 Rep Power: 0	How to return to an instance? I am having a problem. If I have a JFrame open in a class and it performing and processing, when I close it, it still performs the work, which is good because this is what I want it to do. How do I actually return to that instance of the running program, if I go back to the main menu and click the button to load it up again, it makes a brand new instance. I need to return to the already running one. Code for the back button MainMenu m = new MainMenu(); m.setVisible(true); dispose(); Code for loading up JFRAME Again from Main Menu SandHopper sHopper = new SandHopper(); dispose(); sHopper.setVisible(true); If someone can help me out here it would be great. Thank you.

Apr 2nd, 2008, 10:17 AM	#2
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 763 Rep Power: 3	Re: How to return to an instance? You'll want a slightly different design where you keep a SandHopper object and instead of creating a new one each time you set it visible again. You can wrap this into a static method similar to this: (Toggle Plain Text) class SandHopper { private static SandHopper onlySandHopper; public static SandHopper GetSandHopper() { if(onlySandHopper == null) { onlySandHopper = new SandHopper(); } return onlySandHopper; } // .. the rest of your class... } class SandHopper { private static SandHopper onlySandHopper; public static SandHopper GetSandHopper() { if(onlySandHopper == null) { onlySandHopper = new SandHopper(); } return onlySandHopper; } // .. the rest of your class... } With this, you might want to make your constructors private, so that only GetSandHopper() can create one. The benefit to this: you reuse the same one all the time. The drawback: you can only have 1 SandHopper (if you want more than one, you can leave the constructors public, but anybody who calls GetSandHopper() will always use the same one). __________________ <insert disclaimer here> <insert shameless plug for Visual Studio here>

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Programming Forums > Application Development > Java

How to return to an instance?