java - 广告选择面板抛出 JCombobox

Question

当我使用组合框时，我在向框架中添加另一个 JPanel 时遇到问题。我想根据组合框中的选择更改中心面板。我为所有选择创建了不同的面板，但它没有添加到我的主面板中。我添加了代码。

谢谢:)

import AllClasses.FlightCompany;
{
public class WorkerDialog extends JFrame {
    private JPanel Worker;
    private String[] LabelNames = { "Worker Type:", " Worker Name:" };
    String [] str = { "Office", "Host",
    "Pilot" };
    JComboBox<String> ChooseBox = new JComboBox<>(str);
    public JPanel MainPanel;
    private JPanel [] p= new JPanel[3];

    public WorkerDialog(FlightCompany f) {
        super("Worker Dialog");

        p[0] = new Office_Gui();
        p[1] = new Host_Gui();
        p[2] = new Pilot_Gui();
        Worker = new JPanel(new FlowLayout(FlowLayout.LEFT, 5, 5));
        JLabel LabelName = new JLabel(LabelNames[0]);
        JLabel LabelName2 = new JLabel(LabelNames[1]);
        JTextField fieldBox = new JTextField();
        LabelName.setSize(40, 25);
        ChooseBox.setPreferredSize(new Dimension(180, 22));
        Worker.add(LabelName);
        Worker.add(ChooseBox);
        Worker.add(LabelName2);
        fieldBox.setPreferredSize(new Dimension(180, 22));
        Worker.add(fieldBox);
        JPanel AddPanel = new JPanel(new GridLayout(2, 1, 1, 1));
        AddPanel.add(new JButton("Add"));
        AddPanel.add(new JButton("TakeOff"));
        MainPanel = new JPanel(new BorderLayout(3, 3));
        AddPanel.setPreferredSize(new Dimension(0, 110));
        ChooseBox.addItemListener(new ItemListener() {



            @Override
            public void itemStateChanged(ItemEvent e) {
                // TODO Auto-generated method stub
                //String str = e.getActionCommand();
                String jb =  (String) ChooseBox.getSelectedItem();
                if (jb.equals("Office")){

                    MainPanel.add(p[0],BorderLayout.CENTER);
                    System.out.println("Office");}
            }
        });








        MainPanel.add(Worker, BorderLayout.NORTH);
        MainPanel.add(AddPanel, BorderLayout.SOUTH);
        add(MainPanel);
        //pack();
        setSize(560, 300);
        setAlwaysOnTop(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setResizable(false);
        setVisible(true);

Answer 1

您想要做的是为您的 mainPanel 使用 CardLayout，这将允许您轻松地在面板之间切换。然后将所有面板添加到 mainPanel 中，并指定面板的名称。该名称将出现在组合框中。当你想显示某个面板时，只需调用cardLayout.show(mainPanel, "nameOfPanel")

要了解有关卡片布局的更多信息，请参阅 How to Use CardLayout 。您还可以看一个简单的例子here

旁白:使用 Java 命名约定。变量以小写字母开头，使用驼峰式大小写。即:

• 选择框 → 选择框
• 主面板 → 主面板
• 等等