java - javafx中的路径拖动

Question

我试图在javafx中创建一个用于路径拖动的事件，但是，使用setLayoutX/Y会将Path元素放在按下鼠标时的光标下方，但会有一个鼠标拖动时平滑拖动。我正在使用 setTranslateX/Y 方法，它不会将 Path 放到光标下方，但是拖动并不平滑，并使 Path 节点向后跳转，拖动时向前。 Path 创建为 freedraw 对象。

我使用以下代码创建路径:

EventHandler<MouseEvent> mouseEventHandler = new EventHandler<MouseEvent>() {
@Override
public void handle (MouseEvent e) {
    if (i == 0) {
    if (e.getEventType() == MouseEvent.MOUSE_PRESSED) {
        j = 1;
        path = new Path();
        path.setStroke(color);
        path.setStrokeWidth(10);
        root.getChildren().add(path);
        path.getElements().add(new MoveTo(e.getX(), e.getY()));
    }
    if (e.getEventType() == MouseEvent.MOUSE_DRAGGED) {
        if (j == 1) {
        path.getElements().add(new LineTo(e.getX(), e.getY()));
        }
    }
    if (e.getEventType() == MouseEvent.MOUSE_RELEASED) {
        if (j == 1) {
        path.getElements().add(new LineTo(e.getX(), e.getY()));
        path.setOnMouseEntered(new PathEventHandler(paths.size()));
        path.setOnMouseExited(new PathEventHandler(paths.size()));
        path.setOnMousePressed(new PathEventHandler(paths.size()));
        path.setOnMouseDragged(new PathEventHandler(paths.size()));
        path.setOnMouseReleased(new PathEventHandler(paths.size()));
        path.setOnMouseClicked(new PathEventHandler(paths.size()));
        paths.add(path);
        cachePath.add(path);
        cacheType.add("Create");
        j = 0;
        }
    }
}

为了从路径列表中拖动创建的路径，我使用以下代码:

class PathEventHandler implements EventHandler<MouseEvent>{
//element number in paths
public int n;
public PathEventHandler(int n){
    this.n=n;
}
@Override
public void handle(MouseEvent me) {
    if (me.getEventType() == MouseEvent.MOUSE_ENTERED) {
        paths.get(n).setEffect(new DropShadow(20, Color.BLACK));
    }
    if (me.getEventType() == MouseEvent.MOUSE_EXITED) {
        paths.get(n).setEffect(null);
    }
    if (i == 2) {
    if (me.getEventType() == MouseEvent.MOUSE_PRESSED) {
        x = me.getX();
        y = me.getY();
    } 
    if (me.getEventType() == MouseEvent.MOUSE_DRAGGED) {
        paths.get(n).setTranslateX(me.getX() - x + paths.get(n).getTranslateX());
        paths.get(n).setTranslateY(me.getY() - y + paths.get(n).getTranslateY()); 
        /*paths.get(n).setTranslateX(me.getX());
        paths.get(n).setTranslateY(me.getY()); */
        listX.add(paths.get(n).getTranslateX());
        listY.add(paths.get(n).getTranslateY());
        x = me.getX();
        y = me.getY();
    }
    if (me.getEventType() == MouseEvent.MOUSE_RELEASED) {
        cachePath.add(paths.get(n));
        cacheType.add("Relocate");
    }
    if (me.getEventType() == MouseEvent.MOUSE_CLICKED) {
        if (me.getButton() == MouseButton.SECONDARY) {
        root.getChildren().remove(paths.get(n));
        cachePath.add(paths.get(n));
        cacheType.add("Remove");
        }
    }
    }
}

Answer 1

您必须将路径添加到组，然后才能平滑拖动。我不知道您为什么要使用路径列表，但这不需要进一步，因为我们有一个由组对象扭曲的路径对象，您可以在那里对路径对象进行更改。如果由于某种原因您仍然需要列表，您可以将 Group 对象收集到列表中，然后使用它来装饰路径。

然后看看这个并进行这些更改

  if (e.getEventType() == MouseEvent.MOUSE_RELEASED) {
                    if (j == 1) {
                        paths.add(path);
                        root.getChildren().add(new DragablePath(path));
                        cachePath.add(path);
                         cacheType.add("Create");


                    }
                }

这里是DragablePath类和DragContext类。您可以像使用“路径事件处理程序”一样使用“DragablePath 事件处理程序”。

class DragablePath extends Group {

    private final Node node;

    DragablePath(Node node) {
        this.node = node;
        this.getChildren().add(node);
        final DragContext dragContext = new DragContext();
        this.addEventFilter(
                MouseEvent.ANY,
                new EventHandler<MouseEvent>() {
                    @Override
                    public void handle(final MouseEvent mouseEvent) {
                        mouseEvent.consume();

                    }
                });
       this.addEventFilter(
                MouseEvent.MOUSE_ENTERED,
                new EventHandler<MouseEvent>() {
                    @Override
                    public void handle(final MouseEvent mouseEvent) {
                        node.setEffect(new DropShadow(20, Color.BLACK));

                    }
                });
        this.addEventFilter(
                MouseEvent.MOUSE_EXITED,
                new EventHandler<MouseEvent>() {
                    @Override
                    public void handle(final MouseEvent mouseEvent) {
                        node.setEffect(null);

                    }
                });

        this.addEventFilter(
                MouseEvent.MOUSE_PRESSED,
                new EventHandler<MouseEvent>() {
                    @Override
                    public void handle(final MouseEvent mouseEvent) {
                        dragContext.mouseAnchorX = mouseEvent.getX();
                        dragContext.mouseAnchorY = mouseEvent.getY();
                        dragContext.initialTranslateX = node.getTranslateX();
                        dragContext.initialTranslateY = node.getTranslateY();

                    }
                });
        this.addEventFilter(
                MouseEvent.MOUSE_DRAGGED,
                new EventHandler<MouseEvent>() {
                    @Override
                    public void handle(final MouseEvent mouseEvent) {

                        node.setTranslateX(
                                dragContext.initialTranslateX
                                + mouseEvent.getX()
                                - dragContext.mouseAnchorX);
                        node.setTranslateY(
                                dragContext.initialTranslateY
                                + mouseEvent.getY()
                                - dragContext.mouseAnchorY);

                    }
                });
        this.addEventFilter(
                MouseEvent.MOUSE_RELEASED,
                new EventHandler<MouseEvent>() {

                    @Override
                    public void handle(final MouseEvent mouseEvent) {

                    }
                });

    }
}

private static final class DragContext {

    public double mouseAnchorX;
    public double mouseAnchorY;
    public double initialTranslateX;
    public double initialTranslateY;

}

**提示:您可以通过 Shape 的 setSmooth(true) 来启用抗锯齿提示。