Code
class BalloonToolTip extends JToolTip {
private HierarchyListener listener;
@Override public void updateUI() {
removeHierarchyListener(listener);
super.updateUI();
listener = e -> {
Component c = e.getComponent();
boolean b = (e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0;
if (b && c.isShowing()) {
Window w = SwingUtilities.getWindowAncestor(c);
if (w != null && w.getType() == Window.Type.POPUP) {
// Popup$HeavyWeightWindow
w.setBackground(new Color(0x0, true));
}
}
};
addHierarchyListener(listener);
setOpaque(false);
setBorder(BorderFactory.createEmptyBorder(8, 5, 0, 5));
}
@Override public Dimension getPreferredSize() {
Dimension d = super.getPreferredSize();
d.height = 28;
return d;
}
@Override public void paintComponent(Graphics g) {
Shape s = makeBalloonShape();
Graphics2D g2 = (Graphics2D) g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setColor(getBackground());
g2.fill(s);
g2.setColor(getForeground());
g2.draw(s);
g2.dispose();
super.paintComponent(g);
}
private Shape makeBalloonShape() {
Insets i = getInsets();
int w = getWidth() - 1;
int h = getHeight() - 1;
int v = i.top / 2;
Polygon triangle = new Polygon();
triangle.addPoint(i.left + v + v, 0);
triangle.addPoint(i.left + v, v);
triangle.addPoint(i.left + v + v + v, v);
Area area = new Area(new RoundRectangle2D.Float(
0, v, w, h - i.bottom - v, i.top, i.top));
area.add(new Area(triangle));
return area;
}
}
//...
JList<String> list = new JList<String>(model) {
@Override public JToolTip createToolTip() {
JToolTip tip = new BalloonToolTip();
tip.setComponent(this);
return tip;
}
};
References
