Question

我正在写一个DnD程序来实现拖动功能。在调整框架大小之前，一切正常。 JLabel在面板内部没有任何问题。但是，当我尝试调整窗口大小时，JLabel会弹回原来的位置（幸运的是，DnD功能仍然可行）。如何防止JLabel回弹到原来的位置？它是否与重绘函数有关？（也许我必须重写函数？）这是我的JFrame构造函数的代码：

    JMenuBar menuBar = new JMenuBar();
    setJMenuBar(menuBar);
    getContentPane().setLayout(new BorderLayout(0, 0));

    textField = new JTextField();
    getContentPane().add(textField, BorderLayout.NORTH);
    textField.setColumns(10);

    MainPanel = new JPanel();
    getContentPane().add(MainPanel, BorderLayout.CENTER);
    MainPanel.setLayout(new GridLayout(1, 0, 0, 0));


    Left_Panel = new JPanel();
    Left_Panel.setTransferHandler(new DragAndDropTransferHandler());
    Left_Panel.setDropTarget(new DropTarget(MainFrame.this, new MyDropTargetListener(this)));
    Left_Panel.setBorder(new TitledBorder("Panel 1"));
    MyLabel ML = new MyLabel();
    ML.setBounds(50 , 70, 61, 16);
    Left_Panel.add(ML);
    MainPanel.add(Left_Panel);

    Right_Panel = new JPanel();
    Right_Panel.setBounds(201, 0, 200, 400);
    Right_Panel.setTransferHandler(new DragAndDropTransferHandler());
    Right_Panel.setDropTarget(new DropTarget(MainFrame.this, new MyDropTargetListener(this)));
    Right_Panel.setBorder(new TitledBorder("Panel 2"));
    MainPanel.add(Right_Panel);

    this.setVisible(true);
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);

这是我的目标侦听器的drop函数。

    @Override
public void drop(DropTargetDropEvent dtde) {
    DataFlavor dragAndDropPanelFlavor = null;
    Object transferableObj = null;
    Transferable transferable = null;

    try {
        dragAndDropPanelFlavor = MainFrame.getFlavor();
        transferable = dtde.getTransferable();
        dtde.getDropTargetContext();
        // What does the Transferable support
        if (transferable.isDataFlavorSupported(dragAndDropPanelFlavor)) {
            transferableObj = dtde.getTransferable().getTransferData(dragAndDropPanelFlavor);
        } 

    } catch (Exception ex) { 
        System.out.println("Error");
    }

    if (transferableObj == null) return;
    if (transferableObj instanceof MyLabel) {
        MyLabel ML = (MyLabel) transferableObj;
        ML.setBounds(dtde.getLocation().x, dtde.getLocation().y, 61, 16);
    } 
}

我目前只在左侧面板上工作。告诉我是否需要提供更多代码。

用Java调整dnd面板的大小

0 个答案: