Question

I have a JDialog object that, quite simply, MUST be 200 pixels wide, regardless of its contents.

I need to be able to have the height adjusted dynamically, to always ensure that all the content is shown. How do I go about it?

• I’ve tried overriding JDialog.getPreferredSize() method, but I can’t figure out what to add for the height value.
• I’ve tried checking if the main JPanel isValid() and isShowing(), however, both return true as long as a part of the Panel is actually visible.

Answer 1

Preferred sizes are only for layout managers, they cannot restrict window sizes.

The window peer has a method for enforcing minimum size, so that works very well, but there is nothing for maximum size other than listening for resizes and resetting to desired size:

    setMinimumSize(new Dimension(200, Integer.MAX_VALUE));
    addComponentListener(new ComponentAdapter() {
        @Override
        public void componentResized(ComponentEvent e) {
            Dimension size = getSize();
            size.width = 200;
            setSize(size);
        }
    });