问题描述

我已经实现了这个非常基本的，在两个 JPanel 之间拖放，但这并不能真正满足我的要求！

I've implemented this very basic, drag and drop between two JPanels, but this doesn't really meet my requirements!

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，我在这里不是很清楚.我试图将 ImageIcon 从图像选择面板上的 JLabel 拖到故事情节面板的另一个 JLabel 上.我可以用上面的代码做到这一点.但是当我这样做时，我可以从图像选择面板中拖动一个 ImageIcon，并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动到图像选择面板，这是我不想要的.

Sorry I wasn't very clear here. Im trying to drag an ImageIcon from a JLabel on the imageselect panel, to another JLabel the storyline panel. I can do this, with the above code. But when I do this, I can drag an ImageIcon from the imageselect panel, and replace another ImageIcon on the same panel. I do NOT want this to happen. I can also drag from the storyline panel to the imageselect panel, which I do NOT want.

我不是要求被勺子喂食代码，我只是在寻找正确方向的推动力！

I'm not asking to be spoon fed code, I'm just looking for a push in the right direction!

我想知道是否有任何方法可以计算成功的拖放操作，下面的解决方案回答了我原来的问题.

I'm wondering is there any way of counting a successful drag and drop operation, the solution below answered my original question.

推荐答案

这基本上是@Andrew 评论的大纲 - 由于您的 SSCCE 很容易实现 :-)

This is basically an outline of @Andrew's comment - easily possible due to your SSCCE :-)

子类 TransferHandler，覆盖 canImport 以检查源标签是否在 imageSelect 面板上，如果是则拒绝.

Subclass TransferHandler, override canImport to check if the source label is on the imageSelect panel and reject if so.

    // 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)

这篇关于爪哇.拖动&将 ImageIcon 从面板 1 上的 JLabel 拖放到面板 2 上的 JLabel.添加计数器功能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！