Question

我正在使用JavaFX2上的拖放操作。拖拉对象（可能是被拖动对象的克隆）可能跟在鼠标光标之后，就像在JavaFX场景生成器上一样。

这是我的示例源代码：

Pane pane;
private void dragAndDropExample() {
    pane = new Pane();
    pane.setPrefSize(800, 600);
    TitledPane titlePane = new TitledPane("Partial Order", pane);
    add(titlePane, 0, 2);

    pane.getChildren().add(createCircle(350, 300, Color.RED));
    pane.getChildren().add(createCircle(250, 300, Color.BROWN));

    pane.setOnMouseMoved(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) { 
            if (circleToMove != null) { 
                circleToMove.setCenterX(event.getX());
                circleToMove.setCenterY(event.getY()); 
            }

        }
    });
}

Circle circleToMove;

private Circle createCircle(double x, double y, Color color) {
    final Circle c = new Circle(x, y, 25);
    c.setFill(color);

    c.setOnDragDetected(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent arg0) {
            System.out.println("SetOnDragDetected");
            c.setFill(Paint.valueOf("blue"));
            Dragboard db = c.startDragAndDrop(TransferMode.COPY_OR_MOVE);
            ClipboardContent content = new ClipboardContent();
            content.putString("foo " + c.hashCode());
            db.setContent(content);
            arg0.consume();
            circleToMove = c;
        }
    });

    c.setOnMouseClicked(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {
            System.out.println("Mouse clicked");
        }
    });

    c.setOnMouseReleased(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {
            System.out.println("Mouse Released");
            circleToMove = null;
        }
    });

    c.setOnDragExited(new EventHandler<DragEvent>() {

        @Override
        public void handle(DragEvent event) {
            System.out.println("SetOnDragExited");
            System.out.println(event.getGestureSource());

        }
    });

    c.setOnDragOver(new EventHandler<DragEvent>() {

        @Override
        public void handle(DragEvent event) {
            System.out.println("setOnDragOver " + c.hashCode());
            c.setFill(Paint.valueOf("white"));
            event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
            event.consume();
        }
    });

    c.setOnDragDropped(new EventHandler<DragEvent>() {

        @Override
        public void handle(DragEvent arg0) {
            System.out.println("setOnDragDropped");
            c.setFill(Paint.valueOf("black"));

            if (arg0.getGestureSource() instanceof Circle) {

                if (arg0.getDragboard().hasString()) {
                    System.out.println(c.hashCode() + " hat jetzt " + arg0.getDragboard().getString());
                }
            }
        }
    });

    c.setOnDragEntered(new EventHandler<DragEvent>() {

        @Override
        public void handle(DragEvent arg0) {
            System.out.println("setOnDragEntered");

        }
    });

    return c;
}

我尝试在窗格上使用mouseEvent，但在拖放过程中不会触发此事件。

Answer 1

您使用的是错误的处理程序。拖动事件用于在窗格之间拖动项目。如果您只想移动被处理对象，请使用下一个代码：

private Circle createCircle(double x, double y, Color color) {
    final Circle c = new Circle(x, y, 25);
    c.setFill(color);

    c.setOnMouseDragged(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {
            c.relocate(event.getSceneX() - c.getRadius(), event.getSceneY() - c.getRadius());
        }
    });

    return c;
}

您也可以尝试查看Ensemble demo:

中的下一个子样本

javafx拖放移动图标

1 个答案: