java - 鼠标拖动手势

Question

我正在尝试拖动节点并将它们放在彼此之上。这是一个简单的类，我希望它会对拖动手势使用react，但它不会

public class CircleDrag extends Circle
{

    double x, y;
    String name;
    int count = 0;

    public CircleDrag(double centerX, double centerY, String name)
    {
        super(centerX, centerY, 10);
        this.name = name;

        setOnDragDetected(e ->
        {
            startFullDrag();
            startDragAndDrop(TransferMode.ANY); // tried with and without this line.
            logIt(e);
        });

        setOnDragEntered(e ->
        {
            logIt(e);
        });

        setOnDragDone(e ->
        {
            logIt(e);
        });

        setOnDragOver(e ->
        {
            logIt(e);
        });

        setOnMousePressed(e ->
        {
            logIt(e);
            setMouseTransparent(true);
            x = getLayoutX() - e.getSceneX();
            y = getLayoutY() - e.getSceneY();
        });

        setOnMouseReleased(e ->
        {
            logIt(e);
            setMouseTransparent(false);
        });

        setOnMouseDragged(e ->
        {
            logIt(e);
            setLayoutX(e.getSceneX() + x);
            setLayoutY(e.getSceneY() + y);
        });

    }

    private void logIt(Event e)
    {
        System.out.printf("%05d %s: %s\n", count++, name, e.getEventType().getName());
    }

}

我期望将一堆 CircleDrags 添加到一个 Pane 中，当将一个 CircleDrags 拖到另一个上时，另一个会触发 onDrag* 事件。但事实并非如此。

我不明白这个手势是什么意思？

谢谢奥利。

Answer 1

一般情况下，您可以这样做:

import java.util.ArrayList;
import java.util.List;

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.input.MouseEvent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;

public class PhysicsTest extends Application {

    public static List<Circle> circles = new ArrayList<Circle>();

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

    @Override
    public void start(Stage primaryStage) {

        Group root = new Group();

        Circle circle1 = new Circle( 50);
        circle1.setStroke(Color.GREEN);
        circle1.setFill(Color.GREEN.deriveColor(1, 1, 1, 0.3));
        circle1.relocate(100, 100);

        Circle circle2 = new Circle( 50);
        circle2.setStroke(Color.BLUE);
        circle2.setFill(Color.BLUE.deriveColor(1, 1, 1, 0.3));
        circle2.relocate(200, 200);


        MouseGestures mg = new MouseGestures();
        mg.makeDraggable( circle1);
        mg.makeDraggable( circle2);

        circles.add( circle1);
        circles.add( circle2);

        root.getChildren().addAll(circle1, circle2);

        primaryStage.setScene(new Scene(root, 1600, 900));
        primaryStage.show();
    }



public static class MouseGestures {

    double orgSceneX, orgSceneY;
    double orgTranslateX, orgTranslateY;

    public void makeDraggable( Node node) {
        node.setOnMousePressed(circleOnMousePressedEventHandler);
        node.setOnMouseDragged(circleOnMouseDraggedEventHandler);
    }

    EventHandler<MouseEvent> circleOnMousePressedEventHandler = new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent t) {

            orgSceneX = t.getSceneX();
            orgSceneY = t.getSceneY();

            Circle p = ((Circle) (t.getSource()));

            orgTranslateX = p.getCenterX();
            orgTranslateY = p.getCenterY();
        }
    };

    EventHandler<MouseEvent> circleOnMouseDraggedEventHandler = new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent t) {

            double offsetX = t.getSceneX() - orgSceneX;
            double offsetY = t.getSceneY() - orgSceneY;

            double newTranslateX = orgTranslateX + offsetX;
            double newTranslateY = orgTranslateY + offsetY;

            Circle p = ((Circle) (t.getSource()));

            p.setCenterX(newTranslateX);
            p.setCenterY(newTranslateY);

            for( Circle c: circles) {

                if( c == p)
                    continue;

                if( c.getBoundsInParent().intersects(p.getBoundsInParent())) {
                    System.out.println( "Overlapping!");
                }
            }
        }
    };

}

}

请注意，此解决方案使用父级中的边界，即最后一个矩形用于重叠检查。如果您想使用圆检查，您可以使用半径并检查圆之间的距离。取决于您的要求。