Change a layout of a JPopupMenu to use their iconic menu items

• download example.jar
• download src.zip
• repository

Code

JPopupMenu popup = new JPopupMenu();
GridBagConstraints c = new GridBagConstraints();
popup.setLayout(new GridBagLayout());
c.gridheight = 1;

c.weightx = 1.0;
c.weighty = 0.0;
c.fill = GridBagConstraints.HORIZONTAL;
c.anchor = GridBagConstraints.CENTER;

c.gridwidth = 1;
c.gridy = 0;
c.gridx = 0; popup.add(makeButton("\u21E6"), c);
c.gridx = 1; popup.add(makeButton("\u21E8"), c);
c.gridx = 2; popup.add(makeButton("\u21BB"), c);
c.gridx = 3; popup.add(makeButton("\u2729"), c);

c.gridwidth = 4;
c.gridx = 0;
c.insets = new Insets(2, 0, 2, 0);
c.gridy = 1; popup.add(new JSeparator(), c);
c.insets = new Insets(0, 0, 0, 0);
c.gridy = 2; popup.add(new JMenuItem("aaaaaaaaaa"), c);
c.gridy = 3; popup.add(new JPopupMenu.Separator(), c);
c.gridy = 4; popup.add(new JMenuItem("bbbb"), c);
c.gridy = 5; popup.add(new JMenuItem("ccccccccccccccccccccc"), c);
c.gridy = 6; popup.add(new JMenuItem("dddddddddd"), c);

final Icon icon = new SymbolIcon(symbol);
JMenuItem b = new JMenuItem() {
  private final Dimension d = new Dimension(icon.getIconWidth(), icon.getIconHeight());
  @Override public Dimension getPreferredSize() {
    return d;
  }
  @Override public void paintComponent(Graphics g) {
    super.paintComponent(g);
    Dimension cd = getSize();
    Dimension pd = getPreferredSize();
    int offx = (int) (.5 + .5 * (cd.width  - pd.width));
    int offy = (int) (.5 + .5 * (cd.height - pd.height));
    icon.paintIcon(this, g, offx, offy);
  }
};
b.setOpaque(true);

References

• Change a layout of a JPopupMenu to use their iconic menu items(Japanese)

Forward a mouse wheel scroll event in nested JScrollPane to the parent JScrollPane

• download example.jar
• download src.zip
• repository

Code

class WheelScrollLayerUI extends LayerUI {
  @Override public void installUI(JComponent c) {
    super.installUI(c);
    if (c instanceof JLayer) {
      ((JLayer) c).setLayerEventMask(AWTEvent.MOUSE_WHEEL_EVENT_MASK);
    }
  }
  @Override public void uninstallUI(JComponent c) {
    if (c instanceof JLayer) {
      ((JLayer) c).setLayerEventMask(0);
    }
    super.uninstallUI(c);
  }
  @Override protected void processMouseWheelEvent(
      MouseWheelEvent e, JLayer l) {
    Component c = e.getComponent();
    int dir = e.getWheelRotation();
    JScrollPane main = l.getView();
    if (c instanceof JScrollPane && !c.equals(main)) {
      JScrollPane child = (JScrollPane) c;
      BoundedRangeModel m = child.getVerticalScrollBar().getModel();
      int extent  = m.getExtent();
      int minimum = m.getMinimum();
      int maximum = m.getMaximum();
      int value   = m.getValue();
      if (value + extent >= maximum && dir > 0 || value <= minimum && dir < 0) {
        main.dispatchEvent(SwingUtilities.convertMouseEvent(c, e, main));
      }
    }
  }
}

References

• Forward a mouse wheel scroll event in nested JScrollPane to the parent JScrollPane(Japanese)