java - Javafx在特定条件下每10毫秒触发一个事件

Question

您好，我试图在检测到拖动但鼠标尚未释放的情况下每 10 毫秒触发一个事件。下面是我想要触发的代码。

mapScroll.addEventFilter(MouseEvent.MOUSE_DRAGGED, e -> {
        endX = e.getX();
        endY = e.getY();
        Bounds viewBounds = mapScroll.getViewportBounds();
        double startEndX = startX - endX;
        double startEndY = startY - endY;

        Bounds contentBounds = mapScroll.getContent().getLayoutBounds();

        double hChange = startEndX / (contentBounds.getWidth() - viewBounds.getWidth());
        double vChange = startEndY / (contentBounds.getHeight() - viewBounds.getHeight());
        mapScroll.setHvalue(mapScroll.getHvalue() + hChange);
        mapScroll.setVvalue(mapScroll.getVvalue() + vChange);

        startX = endX;
        startY = endY;
    });

不幸的是，在我尝试在事件中使用预定执行程序服务之前，但这无法正常工作。

Answer 1

只需添加检查自上次执行以来是否已过去 10 毫秒。 (我使用了 LongProperty，因为带有 Lambda 的 final restriction)

final LongProperty timeOfLastExecute = new SimpleLongProperty(System.currentTimeMillis());

mapScroll.addEventFilter(MouseEvent.MOUSE_DRAGGED, e -> {
        if(System.currentTimeMillis() - timeOfLastExecute.get() > 10) {
            endX = e.getX();
            endY = e.getY();
            Bounds viewBounds = mapScroll.getViewportBounds();
            double startEndX = startX - endX;
            double startEndY = startY - endY;

            Bounds contentBounds = mapScroll.getContent().getLayoutBounds();

            double hChange = startEndX / (contentBounds.getWidth() - viewBounds.getWidth());
            double vChange = startEndY / (contentBounds.getHeight() - viewBounds.getHeight());
            mapScroll.setHvalue(mapScroll.getHvalue() + hChange);
            mapScroll.setVvalue(mapScroll.getVvalue() + vChange);

            startX = endX;
            startY = endY;
            timeOfLastExecute.set(System.currentTimeMillis());
        }
    });