Problems with dispose();

Question

In my program when a button is clicked the JFrame I'm using should close. However the dispose() method doesn't seems to work. Could anyone help me?

public class SetUp extends JFrame implements ActionListener, Checker {
    JFrame frame= new JFrame("Set Up");

    public mmSetUp() {      
        setSize(500, 300);

        setLayout(new BorderLayout());

        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setResizable(false);
        setLocationRelativeTo(null);        

        setVisible(true);
        pack();

    }

    public void actionPerformed(ActionEvent e) {

        if (e.getSource() == Submit) {
            windowclose();          
        }
    }

    public void windowclose() {

        frame.dispose();
    }
}

For better help sooner, post an [MCVE](http://stackoverflow.com/help/mcve) (Minimal Complete and Verifiable Example). — Andrew Thompson, Jul 09 '14 at 23:45

score 2 · Answer 1 · edited May 23 '17 at 12:11

Well after checking your code it's probably because of your class extends JFrame and you're adding all your elements to this extended frame.

But you also create a JFrame, this isn't a good practice, 1st of all see The use of multiple JFrames, Good / Bad Practice about using multiple frames.

Now going back into your code, let's see about it, as I said before, you're extending a JFrame on your class like this (I'll refer to this frame as frame1)

public class SetUp extends JFrame implements ActionListener, Checker {

But you also create a JFrame here (I'll refer to this frame frame2):

JFrame frame= new JFrame("Set Up");

You are trying to dispose the frame2, it's actually happening that, but if you want to dispose frame1 (which is the one which has all your elements, i.e. the one you're working with), then on this method, you should change:

public void windowclose() {
    frame.dispose();
}

for this one:

public void windowclose() {

    this.dispose();
}

Also I don't recommend you to extend from JFrame class it's better to create objects from it like you did.

But if you do so, then you should change your code as follows:

public mmSetUp() {  

    frame.setSize(500, 300);

    frame.setLayout(new BorderLayout());

    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    frame.setResizable(false);
    frame.setLocationRelativeTo(null);        

    frame.setVisible(true);
    frame.pack();
}

public void actionPerformed(ActionEvent e) {

    if (e.getSource() == Submit) {
        windowclose();          
    }
}

public void windowclose() {

    frame.dispose();
}

I'm not 100% sure this works or compiles, since I'm not at my PC atm, so I can't create a full example, but at 1st view that's what is happening on your class. In 3 more hours or so, I can post a compilable example.

But please check it

score 2 · Answer 2 · answered Jul 10 '14 at 00:40

You have 2 JFrames. One, that is being extended. Two, the one called frame.

First of all, you have only made one mistake.

Change windowclose() to:

public void windowclose() {
    dispose(); // Removed frame part
}

What you have done is, completely set up the extended JFrame from the start and left frame alone so its idle.

When windowclose() is called, it disposes the idle frame which essentially is useless as you have not even modified anything except for the title.

After you have changed windowclose() the code should work, now you can get rid of

JFrame frame= new JFrame("Set Up");

But if you want to keep everything neater, do as Frakcool said and remove extends JFrame

markspace · Answer 3 · 2014-07-09T22:22:20.177

1

I think you want to call frame.setVisible( false ) instead.

Edit: your program has several logic errors. Try this version instead:

  public class WindowCloseTest
  {
     public static void main( String[] args )
     {
        new SetUp().mmSetUp();
     }
  }
  class SetUp implements ActionListener {
      JFrame frame= new JFrame("Set Up");

      public void mmSetUp() {      
          frame.setSize(500, 300);

          JButton b = new JButton( "Submit");
          b.addActionListener(this);
          frame.add( b, BorderLayout.SOUTH );

          frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
          frame.setLocationRelativeTo(null);        
          frame.pack();
          frame.setVisible(true);
      }

      public void actionPerformed(ActionEvent e) {
         System.out.println( e );
          if (e.getActionCommand() == "Submit") {
              windowclose();          
          }
      }

      public void windowclose() {

          frame.dispose();
      }

  }

edited Jul 09 '14 at 22:22

answered Jul 09 '14 at 22:02

markspace

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that doesn't work either :( – user2104510 Jul 09 '14 at 22:05
Are you calling it before you dispose the JFrame or after? – APerson Jul 09 '14 at 22:06
i tried both and neither worked – user2104510 Jul 09 '14 at 22:09
Well, you have several other errors in your code. Mostly just logic errors. I'll get a working program similar to yours posted in a sec. – markspace Jul 09 '14 at 22:19
the errors may be there as i missed out a lot of code when i copied it in to here, but thanks – user2104510 Jul 09 '14 at 22:21
Compare strings with `.equals()` not `==`. – BitNinja Jul 09 '14 at 22:28
Fair, but the Java spec says all program constant strings that are the same are the same object, so for this example I'm safe. (In other words, it works, I tried it.) – markspace Jul 09 '14 at 22:33
comparing this to my original code i cannot see any differences and it still hasn't solved it – user2104510 Jul 09 '14 at 22:36
Well, cut and paste the code and diff it, I made several lines worth of changes. – markspace Jul 09 '14 at 22:36
i have done and it doesnt seem to make any difference, the program calls the windowclosed method but it doesnt work from there – user2104510 Jul 09 '14 at 22:40
Obviously then your program has problems that you haven't shown us, because my example works 100%. – markspace Jul 09 '14 at 22:42

score 0 · Answer 4 · answered Jul 10 '14 at 00:13

I agree with @user2338547, there are some code you didn't show us that might cause the problem, I code my version of the use for dispose method, hope it can give you some idea of how to use the method

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;

    public class GuiTest extends JFrame{

        static GuiTest frame=new GuiTest("test");
        private JPanel panel=new JPanel();
        private JButton button=new JButton("close");
        private Button buttonListener=new Button();

        public GuiTest(String title){
            super(title);
            add(panel);
            panel.add(button);
            button.addActionListener(buttonListener);
        }
        public static void main(String[] args){
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
            frame.setSize(100,100);
            frame.setVisible(true);
        }
        class Button implements ActionListener{
            public void actionPerformed(ActionEvent e){
            frame.dispose();
            }
        }
    }

Problems with dispose();

4 Answers4