java - 我应该把这条声明 'setJMenuBar(menuBar);' 放在哪里？

Question

主类:

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;


public class Main extends JFrame {

public static void main(String[] args) {
    JFrame frame  = new JFrame("Checking Account Actions");
    frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

    CheckingAccountActions panel = new CheckingAccountActions();

    MyWindowAdapter winAdapter = new MyWindowAdapter(panel);
    frame.addWindowListener(winAdapter);

    frame.getContentPane().add(panel);
    frame.pack();

    frame.setVisible(true);
}

} // Main()

class MyWindowAdapter extends WindowAdapter {
private CheckingAccountActions saved;

public MyWindowAdapter(CheckingAccountActions saved) {
    this.saved = saved;
}

// in your window closing method
// check the state of checkActions first before doing anything
public void windowClosing(WindowEvent e) {
    // note -- don't check for saved in a static way
    // use a method on the instance.
    if(!saved.saved) {
        String  message = "The data in the application is not saved.\n"
                        + "Would you like to save it before exiting the
                                            +  application?";
        int confirm = JOptionPane.showConfirmDialog (null, message);

        if (confirm == JOptionPane.YES_OPTION)
            CheckingAccountActions.chooseFile(2);
    }

    JFrame frame = (JFrame)e.getSource();
    frame.setVisible(false);

    // Main.frame.setVisible(false);
    System.exit(0);
}

} // MyWindowAdapter()

如您所见，此类扩展了 JPanel，这是初始化我的菜单项的地方，但是我是否将主类用于此语句“setJMenuBar(menuBar);”，因为它在 CheckingAccountActions 中给出错误，因为 JFrame 在主要。

CheckingAccountActions 类:

public class CheckingAccountActions extends JPanel {
// Panel
private JLabel         message;

// Menu
private JMenuBar           menuBar;

private JMenu          File;
private JMenuItem      Read, Write;

private JMenu          Account;
private JMenuItem      NewAccount, ListAccounts, ListChecks, ListDeposits, FindAccount;

private JMenu          Transactions;
private JMenuItem      AddTransactions;

// code...
//
//
// code...

public CheckingAccountActions() {


//************************** PANEL *****************************************
// JLabel
    message = new JLabel("Please choose one of the items: ");
    message.setFont(new Font("Helvetica", Font.BOLD, 15));

    CheckingAccountActionsListener listener = new CheckingAccountActionsListener();

//************************** MENU ******************************************
// Menu
    File  = new JMenu("File");
// MenuItem
    Read  = new JMenuItem("Read from file");
    Write = new JMenuItem("Write to file");
// ActionListener
    Read.addActionListener(listener);
    Write.addActionListener(listener);
// Add Buttons to Menu
    File.add(Read);
    File.add(Write);

// Menu
    Account = new JMenu("Account");
// MenuItem
    NewAccount   = new JMenuItem("Add new account");
    ListAccounts = new JMenuItem("List accounts transaction");
    ListChecks   = new JMenuItem("List all checks");
    ListDeposits = new JMenuItem("List all deposits");
    FindAccount  = new JMenuItem("Find an account");
// ActionListener
    NewAccount.addActionListener(listener);
    ListAccounts.addActionListener(listener);
    ListChecks.addActionListener(listener);
    ListDeposits.addActionListener(listener);
    FindAccount.addActionListener(listener);
// Add Buttons to Menu
    Account.add(NewAccount);
    Account.add(ListAccounts);
    Account.add(ListChecks);
    Account.add(ListDeposits);
    Account.add(FindAccount);


// Menu
    Transactions = new JMenu("Transactions");
// MenuItem
    AddTransactions = new JMenuItem("Add Transactions");
// ActionListener
    AddTransactions.addActionListener(listener);
// Add Buttons to Menu
    Transactions.add(AddTransactions);

// MenuBar
    menuBar = new JMenuBar();
    menuBar.add(File);
    menuBar.add(Account);
    menuBar.add(Transactions);

    setBackground(Color.white);
    setPreferredSize(new Dimension(240, 250));
    setJMenuBar(menuBar);
}

private class CheckingAccountActionsListener implements ActionListener {

// code...

}

编辑:我感到困惑的是当框架在另一个类中时如何将我的菜单栏添加到框架？

最终编辑:我让它工作了。我刚刚将所有 JFrame 组件移至 CheckingAccountActions 类。

Answer 1

查看 How to Use Menus 上的 Swing 教程部分. MenuDemo 示例将向您展示一种构建程序的方法。

它还向您展示了在事件调度线程上创建 GUI 的正确方法。