java.awt.event.MouseWheelListener#mouseWheelMoved()源码实例Demo

private void handleMouseWheelEvent(MouseWheelEvent evt, MouseWheelListener delegate) {
    if (scrollpane.isWheelScrollingEnabled() &&
        evt.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL)
    {
        mouseWheelMoved(evt);
        evt.consume();
    } else {
        delegate.mouseWheelMoved(evt);
    }
}
 

/**
 * Called when the mouse wheel is moved.
 * If CTRL key is down, modify current zoom ratio accordingly, otherwise
 * forward the wheel event to proper container (JScrollPane usually).
 *
 * @param e the mouse wheel event
 */
@Override
public void mouseWheelMoved (MouseWheelEvent e)
{
    // CTRL is down?
    if (e.isControlDown()) {
        double ratio = zoom.getRatio();

        if (e.getWheelRotation() > 0) {
            ratio /= factor;
        } else {
            ratio *= factor;
        }

        zoom.setRatio(ratio);
    } else {
        // Forward event to some container of the component?
        Container container = component.getParent();

        while (container != null) {
            if (container instanceof JComponent) {
                JComponent comp = (JComponent) container;
                MouseWheelListener[] listeners = comp.getMouseWheelListeners();

                if (listeners.length > 0) {
                    for (MouseWheelListener listener : listeners) {
                        listener.mouseWheelMoved(e);
                    }

                    return;
                }
            }

            container = container.getParent();
        }
    }
}
 

/**
 * Redispatch a {@link MouseWheelEvent} to the real {@link MouseWheelListener MouseWheelListeners}
 */
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
	//  Create an altered event to redispatch
	if (scrollAmount != 0) {
		e = createScrollAmountEvent(e);
	}

	//  Redispatch the event to original MouseWheelListener
	for (MouseWheelListener mwl : realListeners) {
		mwl.mouseWheelMoved(e);
	}
}
 

/**
 * Called when the mouse wheel is moved.
 * If CTRL key is down, modify current zoom ratio accordingly, otherwise
 * forward the wheel event to proper container (JScrollPane usually).
 *
 * @param e the mouse wheel event
 */
@Override
public void mouseWheelMoved (MouseWheelEvent e)
{
    // CTRL is down?
    if (e.isControlDown()) {
        double ratio = zoom.getRatio();

        if (e.getWheelRotation() > 0) {
            ratio /= factor;
        } else {
            ratio *= factor;
        }

        zoom.setRatio(ratio);
    } else {
        // Forward event to some container of the component?
        Container container = component.getParent();

        while (container != null) {
            if (container instanceof JComponent) {
                JComponent comp = (JComponent) container;
                MouseWheelListener[] listeners = comp.getMouseWheelListeners();

                if (listeners.length > 0) {
                    for (MouseWheelListener listener : listeners) {
                        listener.mouseWheelMoved(e);
                    }

                    return;
                }
            }

            container = container.getParent();
        }
    }
}