Java。将ImageIcon从面板1的JLabel拖放到面板2的JLabel。添加计数器功能

Question

我已经在两个JPanel之间实现了这种非常基本的拖放操作，但这并不能真正满足我的要求！

public class test extends JFrame {

{    JPanel mainpanel, storypanel, imageselect;



    public test(){

          mainpanel = new JPanel(new BorderLayout());
          storypanel = new JPanel();
          imageselect = new JPanel();
            MouseListener listener = new MouseAdapter(){
            public void mousePressed(MouseEvent e)
        {
            JComponent c = (JComponent) e.getSource();
            TransferHandler handler = c.getTransferHandler();
            handler.exportAsDrag(c, e, TransferHandler.COPY);
        }
        };

            int j = 0;
            BufferedImage myImages;
            JLabel imgselect = new JLabel();
            try { myImages = ImageIO.read(new File("four.jpg"));
            //myImages[j] = resize(myImages[j]);
            imgselect= new JLabel(new ImageIcon(myImages));
            System.out.println(j);
            imageselect.add(imgselect);
            imgselect.addMouseListener(listener);
            imgselect.setTransferHandler(new TransferHandler("icon"));

            } catch(Exception e) {};

            int i = 0;
            BufferedImage storyimages;
            JLabel storylabel = new JLabel();


            //targetImg = new ImageIcon("lmkpackage/base/TargetImg.jpg");
            try{ storyimages = ImageIO.read(new File("TargetImg.jpg"));
            //storyimages[i] = resize(storyimages[i]);
            storylabel = new JLabel(new ImageIcon(storyimages));
            System.out.println(i);
            storypanel.add(storylabel); 
            storylabel.addMouseListener(listener);
            storylabel.setTransferHandler(new TransferHandler("icon"));
            } catch(Exception e) {};


            mainpanel.add(imageselect, BorderLayout.NORTH);
            mainpanel.add(storypanel, BorderLayout.SOUTH);

            getContentPane().add(mainpanel);



        }

        public static void main(String[] args){

        System.out.println("Application Running");
        JFrame mainframe =  new test();
            mainframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainframe.setSize(1000,1000);
            mainframe.setVisible(true);

        }

    }

对不起，我在这里不太清楚。我试图将ImageIcon从imageselect面板上的JLabel拖动到故事情节面板上的另一个JLabel。我可以使用上面的代码来做到这一点。但是，当我这样做时，可以从imageselect面板中拖动一个ImageIcon，然后在同一面板上替换另一个ImageIcon。我不希望这种情况发生。我也可以从故事情节面板拖到不需要的图像选择面板。

我并不是要成为傻瓜式的代码，我只是在寻找正确的方向！

编辑：我想知道有什么方法可以计算成功的拖放操作，下面的解决方案回答了我的原始问题。

Answer 1

这基本上是@Andrew的评论的概述-由于您的SSCCE，很容易实现:-)

子类TransferHandler，重写canImport以检查源标签是否在imageSelect面板上，如果不是，则拒绝。

    // custom transferHandler which decides about imports based on source
    TransferHandler handler = new TransferHandler("icon") {

        @Override
        public boolean canImport(TransferSupport support) {
            return super.canImport(support) 
                    && support.getComponent().getParent() != imageSelectPanel;
        }

    };
    // use the handler on all labels (handlers can be shared, btw)
    // for each label on imageSelectPanel
    imageSelectLabel.setTransferHandler(handler)
    // for each label on the target panel (aka storyPanel) 
    storyLabel.setTransferHandler(handler)