确定是否在JavaFX中使用了事件

我正在尝试用JavaFX中的事件处理做一些离谱的事情。我需要能够确定在手动触发事件后是否已使用该事件

在下面的示例中，正确接收到合成鼠标事件，但是调用consume（）不会更新该事件

我对此进行了调试，发现JavaFX实际上创建了一个新的事件实例，因此原始事件实例保持不变

public class EventManipulation extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        Button button = new Button();
        button.setOnMouseDragged(event -> {
            System.out.println("dragged");
            event.consume();
        });
        primaryStage.setScene(new Scene(new HBox(button), 400, 300));
        primaryStage.show();

        MouseEvent event = new MouseEvent(MouseEvent.MOUSE_DRAGGED, 0, 0, 0, 0, MouseButton.PRIMARY, 1, false, false,
                false, false, false, false, false, false, false, false, null);
        Event.fireEvent(button, event);
        System.out.println(event.isConsumed());  // <== prints false
    }
}

---

我唯一的解决方案就是实现接口。一个相当小的接口如下所示。不幸的是，javafx使用的内置版本位于一个不可访问的包中-

com.sun.javafx.event.EventDispatchChainImpl

private class SimpleChain implements EventDispatchChain {

    private Deque<EventDispatcher> dispatchers = new LinkedList<>();

    @Override
    public EventDispatchChain append(EventDispatcher eventDispatcher) {
        dispatchers.addLast(eventDispatcher);
        return this;
    }

    @Override
    public EventDispatchChain prepend(EventDispatcher eventDispatcher) {
        dispatchers.addFirst(eventDispatcher);
        return this;
    }

    @Override
    public Event dispatchEvent(Event event) {
        if (dispatchers.peekFirst() != null) {
            Event result = dispatchers.removeFirst().dispatchEvent(event, this);
            if (result != null) {
                return result;
            } else {
                event.consume();
                return event;
            }
        } else {
            return event;
        }
    }
}

---

您在哪个线程上启动，事件在哪个线程上调度？可能在JavaFX线程上添加Thread.Sleep（）？@alex440。。。Application.start（）始终在JavaFX线程上运行。@alex440-如果fx内部复制事件，则不会有帮助，或者？我认为函数在事件有机会处理之前终止。

private class SimpleChain implements EventDispatchChain {

    private Deque<EventDispatcher> dispatchers = new LinkedList<>();

    @Override
    public EventDispatchChain append(EventDispatcher eventDispatcher) {
        dispatchers.addLast(eventDispatcher);
        return this;
    }

    @Override
    public EventDispatchChain prepend(EventDispatcher eventDispatcher) {
        dispatchers.addFirst(eventDispatcher);
        return this;
    }

    @Override
    public Event dispatchEvent(Event event) {
        if (dispatchers.peekFirst() != null) {
            Event result = dispatchers.removeFirst().dispatchEvent(event, this);
            if (result != null) {
                return result;
            } else {
                event.consume();
                return event;
            }
        } else {
            return event;
        }
    }
}

Event result = button.buildEventDispatchChain(new SimpleChain()).dispatchEvent(event);
System.out.println(result.isConsumed());