Preventing SWT shell from disposing

Question

I created a SWT dialog with this implementation:

public class FindDialog extends Dialog {
  private DialogResult result;
  private Display display;
  private Shell shell;
  private Button okayButton;
  /*...*/

  public FindDialog(Shell parent) {
    this(parent, SWT.APPLICATION_MODAL | SWT.DIALOG_TRIM);
  }

  public FindDialog(Shell parent, int style) {
    super(parent, style);
    display = getParent().getDisplay();
    initUI();
  }

  public DialogResult open() {
    result = DialogResult.Cancel;
    shell.open();
    while (shell.isVisible()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    return result;
  }

  private void initUI() {
    shell = new Shell(getParent(), getStyle());
    shell.addListener(SWT.Close, new ShellClosingHandler());

    okayButton = new Button(shell, SWT.PUSH);
    okayButton.addListener(SWT.Selection, new ButtonClickedHandler());

    /*...*/
  }

  private class ButtonClickedHandler implements Listener {
    public void handleEvent(Event e) {
      Button button = (Button)e.widget;

      if (button == okayButton) {
        result = DialogResult.OK;
        shell.close();
      }
    }
  }

  private class ShellClosingHandler implements Listener {
    public void handleEvent(Event e) {
      if (result == DialogResult.OK) {
        e.doit = validate();
      }
    }

    private boolean validate() {
      /*...*/
    }
  }
}

There are some more text fields, buttons and checkboxes but I think that it's not important for my question.

The dialog window popups correctly and I can make my changes on the GUI without any problems.

At last I click the ok button and then the following happens:

The SWT.Close event is firing, my validation method is called and depending on the result the dialog is closed or not. That's ok so far.

But shell.close() not only closes the dialog, it also disposes the shell. And exactly here is the problem because

1. I don't want to rebuild the dialog GUI everytime the open method is called. I create all my dialogs at program startup and then only want to open and close it if needed.

2. I need some values of the text fields or states of checkboxes after closing the dialog at different positions in the main program. So it seems a good idea to hold a reference of the dialog object and implement some getters to pull out the data. But if the shell is disposed I have no chance to get the information.

3. If the shell is disposed then I will loose the "state" of the dialog so I have to refill it next time I display the dialog.

So my question: Is there a possibility to prevent the shell from disposing? Or is there another concept that I overlooked so I don't have to restructure my complete dialog set?

Answer 1

if (button == okayButton) {
        result = DialogResult.OK;
        shell.setVisible(false);
      }

You can use setVisible(false) instead of close

So it will get hide and wont get dispose.

You can get the values of the text box after hide

No need to rebuild again

The past values in the textbox will be there after hide.