java - 为什么我的 JPanel 组件会自动填充？

Question

我正在设计应用程序的 GUI，但我的 Swing 组件之间的通信遇到一些问题。我有一个 MainGUI 类，用户单击时必须创建并显示一个新的 JDialog 对象。对话框会按照我想要的方式弹出，但它总是显示我上次访问它时输入的先前值。如何防止这种情况发生？这种行为的原因是什么？我想我在 openActorDialog() 函数上做错了什么。

public class MainGUI extends JPanel {
private ArrayList<Actor> actorList = new ArrayList<Actor>();
private JTextField field = new JTextField(10);
private JButton openDialogeBtn = new JButton("Open Dialog");
private String description;
// here my main gui has a reference to the JDialog and to the
// MyDialogPanel which is displayed in the JDialog

private JDialog dialog;

public MainGUI() {

    setLayout(new BorderLayout(0, 0));
    add(openDialogeBtn);
    field.setEditable(false);
    field.setFocusable(false);

    add(field);

    JMenuBar menuBar = new JMenuBar();
    add(menuBar, BorderLayout.NORTH);

    JMenu mnFile = new JMenu("File");
    menuBar.add(mnFile);

    JMenu mnNew = new JMenu("New");
    mnFile.add(mnNew);

    JMenuItem mntmSystem = new JMenuItem("system");
    mnNew.add(mntmSystem);

    JMenuItem mntmUseCase = new JMenuItem("use case");
    mnNew.add(mntmUseCase);

    JMenuItem mntmActor = new JMenuItem("actor");
    mnNew.add(mntmActor);

    JTree tree = new JTree();
    add(tree, BorderLayout.WEST);

    /*
     * Here we set the actions to be performed when the user interacts
     */

    mntmActor.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            openActorDialog();
        }
    });

}

private void openActorDialog() {
    //Creation of the JDialog
    CreateActorDialog createActorPanel = new CreateActorDialog();
    if (dialog == null) {
        Window win = SwingUtilities.getWindowAncestor(this);
        if (win != null) {
            dialog = new JDialog(win, "Create an actor", ModalityType.APPLICATION_MODAL);
            dialog.getContentPane().add(createActorPanel);
            dialog.setSize(500, 360);
            dialog.setLocationRelativeTo(null);

        }
    }
    dialog.setVisible(true); // here the modal dialog takes over

    // this line starts *after* the modal dialog has been disposed
    // **** here's the key where I get the String from JTextField in the GUI
    // held
    // by the JDialog and put it into this GUI's JTextField.

    Actor a = new Actor(createActorPanel.getActorNameFromDialog(),
            createActorPanel.getActorDescriptionFromDialog());
    field.setText(createActorPanel.getActorNameFromDialog());
    actorList.add(a);
    System.out.println("It is written:" + createActorPanel.getActorDescriptionFromDialog());
    for (Actor actor : actorList) {
        System.out.println(actor.name + " with description :" + actor.description); // Will
                                                                                    // invoke
                                                                                    // override
    }

}

}

Answer 1

在使用之后或使用之前，您必须再次将对话框设置为空，否则您将看到旧的对话框。