Java/Swing：如何将属性从边界传递到模型，反之亦然

Question

我正在构建一个应用程序，用户可以在其中上传图像并在其上绘制矩形以进行注释，并将 cmets 附加到该特定区域/矩形，例如在 Word 或 Docs 中。我对如何在类之间建立联系以传递信息有点困惑。一旦用户绘制了一个矩形并单击它，他们将能够在提供的 JTextField 中编写 cmets，并且程序会将那个矩形与该注释相关联。我有三个班级Box、DrawingArea 和ImageAnnotator。 Box（矩形）的字段/属性之一是bComment，在ImageAnnotator 类中我有一个JButton，单击它时，需要设置从ImageAnnotator 类中的JTextField 检索的字符串到Box.bComment。我知道 onClick 方法应该在ImageAnnotator 类中，因为那是按钮所在的位置，但我对如何将此字符串传递给Box 有点困惑。我应该在ImageAnnotator 中导入Box 并将其设置在onClick 方法中吗？那么现在反过来，在点击矩形时，我如何设置ImageAnnotator中的JTextField和从Box.bComment检索的String，即当用户再次点击同一个矩形时，程序将显示之前添加的在文本字段中发表评论。单击矩形的所有侦听器都在DrawingArea 类内，因此我需要以某种方式从ImageAnnotator 获取文本字段，并用从Box.bComment 检索的字符串填充文本字段。为了更清楚起见，我提供了以下类。

ImageAnnotator.java:

public class ImageAnnotator extends JFrame {

    private JPanel contentPane;
    Model model;
    DrawingArea drawingArea;
    GroupLayout gl_contentPane;
    private JTextField textField;
    private JButton btnNewButton;
    /**
     * Create the frame.
     */
    public ImageAnnotator(Model m) {
        super();
        this.model = m;
        setTitle("Image Annotator");
        ...
        setContentPane(contentPane);
        drawingArea = new DrawingArea();
        
        //ImageName = new JLabel(drawingArea.imageName);
        buttonPanel = new ButtonPanel( drawingArea );
        
        textField = new JTextField(); // this is the text field which will be later set to Box.bComment
        
        btnNewButton = new JButton("Add this comment");//this is the button which needs onClick listener
        
        gl_contentPane = new GroupLayout(contentPane);
        gl_contentPane.setHorizontalGroup(...);
        gl_contentPane.setVerticalGroup(...);
        contentPane.add(drawingArea);
        contentPane.setLayout(gl_contentPane);
    }
    
    // onClick listener should be here for JButton
}

Box.java：

public class Box {
    int bWidth, bHeight, bX, bY;
    String bImageName, bComment;
    
    Color foreground;
    Rectangle rectangle;
    
    public Box(int width, int height) {
        bWidth = width;
        bHeight = height;
    }
    
    public Box(Color foreground, Rectangle rectangle) {
        this.foreground = foreground;
        this.rectangle = rectangle;
    }
    
    public void setComment(String comment) { bComment = comment; }
    public String getComment() { return bComment; }
    
    public void setX(int x) { bX = x; }
    public int getX() { return bX; }
    
    public void setY(int y) { bY = y; }
    public int getY() { return bY; }
   
    public Rectangle getRectangle()
    {
        return rectangle;
    }
}

DrawingArea.java：

public class DrawingArea extends JPanel implements BoxSelectionListener
    {
        private final static int AREA_SIZE = 490;
        private BufferedImage image =
            new BufferedImage(AREA_SIZE, AREA_SIZE, BufferedImage.TYPE_INT_ARGB);
        private Rectangle shape;
        private ArrayList<Box> rectangles = new ArrayList<Box>();
        //public String imageName = ""; // this will store the image/file name

        public DrawingArea()
        {
            setBackground(Color.WHITE);
            MyMouseListener ml = new MyMouseListener();
            addMouseListener(ml);
            addMouseMotionListener(ml);
        }
        
        public void addBoxSelectionListener(BoxSelectionListener listener) {
            listenerList.add(BoxSelectionListener.class, listener);
        }

        public void removeBoxSelectionListener(BoxSelectionListener listener) {
            listenerList.remove(BoxSelectionListener.class, listener);
        }
            
        protected void fireBoxSelected(Box box) {
            BoxSelectionListener[] listeners = listenerList.getListeners(BoxSelectionListener.class);
            // Normally, I'd create a event object, which would wrap the source (this) and
            // the Box together, but if there are no listeners, it's a bit of
            // a waste to do so, so I return early in those cases
            if (listeners.length == 0) {
                return;
            }
            for (BoxSelectionListener listener : listeners) {
                listener.didSelect(box);
            }
        }

        public void didSelect(Box box) {
            // Probably assign this to a "assigned" or "selected" property
            // so it can painted differently
            // And now we want to notify some kind of listener so that
            // it can update the UI as required
            box.setForeground(Color.red);
            box.getComment();
            repaint();
            fireBoxSelected(box);
        }
        
        class MyMouseListener extends MouseInputAdapter
        {
            private Point startPoint;

            public void mousePressed(MouseEvent e) {
                // Mark the clip point
                startPoint = e.getPoint();
            }

            public void mouseDragged(MouseEvent e) {
                // Only create the shape when dragging starts
                if (shape == null) {
                    shape = new Rectangle();
                }
                int x = Math.min(startPoint.x, e.getX());
                int y = Math.min(startPoint.y, e.getY());
                int width = Math.abs(startPoint.x - e.getX());
                int height = Math.abs(startPoint.y - e.getY());

                shape.setBounds(x, y, width, height);
                repaint();
            }

            public void mouseReleased(MouseEvent e) {
                if (shape != null) {
                    if (shape.width != 0 || shape.height != 0) {
                        addRectangle(shape, e.getComponent().getForeground());
                    }
                } else {
                    for (Box b : rectangles) {
                        if (b.getRectangle().contains(e.getPoint())) {
                            didSelect(b);
                            break;
                        }
                        else 
                            b.setForeground(Color.black);
                    }
                }

                startPoint = null;
                shape = null;
            }
        }
        
    }

Answer 1

我可以通过将一些字段设为静态（TextField）来使它们工作，以便我可以从另一个类中引用它，我的错误是我在我的 DrawingArea 类中创建 ImageAnnotator 类的实例，所以当我尝试要从 DrawingArea 内的 ImageAnnotator 引用 TextField，它为空。所以我的解决方案是直接调用 ImageAnnotator 而不创建实例，并将 TextField 设置为静态。