javafx.scene.input.DragEvent#getTarget ( )源码实例Demo

@Override
public void handle(final DragEvent event) {
	final EventTarget target = event.getTarget();
	if (target instanceof Node) {
		dragEntered((Node) target, event);
	}
}
 

@Override
public void handle(final DragEvent event) {
	final EventTarget target = event.getTarget();
	if (target instanceof Node) {
		dragExited((Node) target, event);
	}
}
 

@Override
public void handle(final DragEvent event) {
	final EventTarget target = event.getTarget();
	if (event.getGestureSource() != target
			&& (target instanceof Node)) {
		final Node targetNode = (Node) target;
		dragOver(targetNode, event);
	}
}
 

/**
 * @param target
 *            The targeted {@link Node}
 * @param event
 *            The original {@link DragEvent}
 */
protected void dragOver(final Node target, final DragEvent event) {
	final IViewer viewer = PartUtils.retrieveViewer(getDomain(), target);
	if (viewer == null) {
		return;
	}

	if (viewer instanceof InfiniteCanvasViewer) {
		final InfiniteCanvas canvas = ((InfiniteCanvasViewer) viewer)
				.getCanvas();
		// if any node in the target hierarchy is a scrollbar,
		// do not process the event
		if (event.getTarget() instanceof Node) {
			Node targetNode = (Node) event.getTarget();
			while (targetNode != null) {
				if (targetNode == canvas.getHorizontalScrollBar()
						|| targetNode == canvas.getVerticalScrollBar()) {
					return;
				}
				targetNode = targetNode.getParent();
			}
		}
	}

	final Scene scene = target.getScene();
	if (scene == null) {
		return;
	}

	// determine viewer that contains the given target part
	activeViewer = PartUtils.retrieveViewer(getDomain(), target);
	final List<? extends IOnDragDropHandler> dragDropPolicies = getHandlerResolver()
			.resolve(DragDropGesture.this, target, activeViewer,
					ON_DRAGDROP_HANDLER_KEY);
	setActiveHandlers(activeViewer, dragDropPolicies);
	if (dragDropPolicies != null && !dragDropPolicies.isEmpty()) {
		for (final IOnDragDropHandler dragDropPolicy : dragDropPolicies) {
			dragDropPolicy.dragOver(event);
		}
	}

}