Continuous layout on JFrame resize?

Question

hi,
on my machine (win2k) when you resize a JFrame with the mouse, the contents are not resized until you have released the drag. Is this a property of my java/OS settings or a limitation of Swing?
JSplitPane has a setContinuousLayout method which sounds like it does something similar?
thanks,
asjf

Answer 1

Component and Window listeners are not going to work since the window resize is not happening on the AWT thread.. So, you do need your own thread to monitor the size of the window, and invalidate/validate your window if the size changes. The following should work for you, coded as a method in a utility class so it can be easily reused by any JFrame:
     private static Map continuousLayoutWindows;
     * Sets the specified frame to do a continuous layout, so that if the user resizes the frame,
     * the components within the frame are resized as well.
     * @param frame JFrame
     public static void setContinuousLayout(final JFrame frame) {
          new Timer(100, new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                    Dimension currentSize = frame.getSize();
                    if (continuousLayoutWindows == null) {
                         continuousLayoutWindows = new HashMap();
                    Dimension windowSize = (Dimension)continuousLayoutWindows.get(frame);
                    if (windowSize == null) {
                         windowSize = new Dimension();
                         continuousLayoutWindows.put(frame, windowSize);
                    if (!currentSize.equals(windowSize)) {
                         windowSize.width = currentSize.width;
                         windowSize.height = currentSize.height;
                         SwingUtilities.invokeLater(new Runnable() {
                              public void run() {
                                   frame.invalidate();
                                   frame.validate();
                                   frame.repaint();
          }).start();