在JavaFX矩形邊框畫圓圈

Question

我想在事件onMouseMoved的矩形邊框中添加一些圓圈。 需要使用JavaFX開發圖形，這些圓圈將用於將邊緣連接到圖形節點。 見下圖：

我使用JavaFX。 請看代碼：

public class SampleDragAndDrop extends Application { 

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

@Override 
public void start(final Stage stage) throws Exception { 
    DoubleProperty entity1X = new SimpleDoubleProperty(100); 
    DoubleProperty entity1Y = new SimpleDoubleProperty(100);   

    Entity entity1 = new Entity(Color.STEELBLUE, entity1X, entity1Y); 


    Screen screen = Screen.getPrimary(); 
    Rectangle2D bounds = screen.getVisualBounds(); 
    stage.setX(bounds.getMinX()); 
    stage.setY(bounds.getMinY()); 
    stage.setWidth(bounds.getWidth()); 
    stage.setHeight(bounds.getHeight()); 

    stage.setTitle("Draw circle in rectangle"); 
    stage.setScene(new Scene(new Group(entity1), 400, 400, Color.ALICEBLUE)); 
    stage.show(); 
} 

class Anchor extends Circle { 

    Anchor(Color color, DoubleProperty x, DoubleProperty y) { 
     super(x.get(), y.get(), 20); 
     setFill(color.deriveColor(1, 1, 1, 0.5)); 
     setStroke(color); 
     setStrokeWidth(2); 
     setStrokeType(StrokeType.OUTSIDE); 

     x.bind(centerXProperty()); 
     y.bind(centerYProperty()); 
    } 

class Entity extends Rectangle { 

    Entity(Color color, DoubleProperty x, DoubleProperty y) { 
     setX(x.get()); 
     setY(y.get()); 
     setWidth(120); 
     setHeight(50); 
     setFill(color.deriveColor(1, 1, 1, 0.5)); 
     setStroke(color); 
     setStrokeWidth(2); 
     setStrokeType(StrokeType.OUTSIDE); 
     setArcWidth(20); 
     setArcHeight(20);  


     x.bind(xProperty()); 
     y.bind(yProperty()); 

     enableDrag(); 
    } 

    private void enableDrag() { 
     final Entity.Delta dragDelta = new Entity.Delta(); 
     setOnMousePressed(new EventHandler<MouseEvent>() { 
      @Override 
      public void handle(MouseEvent mouseEvent) { 
       // record a delta distance for the drag and drop operation.      
       dragDelta.x = getX() - mouseEvent.getX(); 
       dragDelta.y = getY() - mouseEvent.getY(); 
       getScene().setCursor(Cursor.MOVE); 
      } 
     }); 
     setOnMouseReleased(new EventHandler<MouseEvent>() { 
      @Override 
      public void handle(MouseEvent mouseEvent) { 
       getScene().setCursor(Cursor.HAND); 
      } 
     }); 
     setOnMouseDragged(new EventHandler<MouseEvent>() { 
      @Override 
      public void handle(MouseEvent mouseEvent) { 
       double newX = mouseEvent.getX() + dragDelta.x; 
       if (newX > 0 && newX < getScene().getWidth()) { 
        setX(newX); 
       } 
       double newY = mouseEvent.getY() + dragDelta.y; 
       if (newY > 0 && newY < getScene().getHeight()) { 
        setY(newY); 
       } 
      } 
     }); 
     setOnMouseEntered(new EventHandler<MouseEvent>() { 
      @Override 
      public void handle(MouseEvent mouseEvent) { 
       if (!mouseEvent.isPrimaryButtonDown()) { 
        getScene().setCursor(Cursor.HAND); 
       } 
      } 
     }); 
     setOnMouseExited(new EventHandler<MouseEvent>() { 
      @Override 
      public void handle(MouseEvent mouseEvent) { 
       if (!mouseEvent.isPrimaryButtonDown()) { 
        getScene().setCursor(Cursor.DEFAULT); 
       } 
      } 
     }); 

     setOnMouseMoved(new EventHandler<MouseEvent>(){ 

      @Override 
      public void handle(MouseEvent mouseEvent) { 
       // Create circles in rectangle here      
      } 
     }); 
    }   

    private class Delta { 
     double x, y; 
    } 
} 
} 

我該怎麼辦？

謝謝！

Answer 1

這工作：

// Create circles in rectangle here      

// Not sure you really need these? 
DoubleProperty leftX = new SimpleDoubleProperty(); 
DoubleProperty leftY = new SimpleDoubleProperty(); 

Anchor leftAnchor = new Anchor(Color.STEELBLUE, leftX, leftY); 
leftAnchor.centerXProperty().bind(xProperty()); 
leftAnchor.centerYProperty().bind(yProperty().add(heightProperty().divide(2))); 
((Group)getParent()).getChildren().add(leftAnchor);