java - 如何删除JMenu Items中的空格

Question

到目前为止，我有这个

这是我的 MyFrame1 源代码:

import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Insets;
import java.awt.Color;
import java.awt.Color.*;
import java.awt.Font;
import java.awt.Font.*;
import java.io.*;
import java.io.BufferedReader;
import java.io.FileReader;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;

public class Test
{
    public static void main(String[] args)
    {
        new Test();
    }

    public Test()
    {
        String line = "";

        EventQueue.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                try
                {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } 
                catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException e)
                {
                    e.printStackTrace();
                }

                JMenuBar mBar = new JMenuBar();

                //creating new JMenuItem
                JMenuItem mHelp = new JMenuItem("Help");
                JMenuItem mCredits = new JMenuItem("Credits");
                JMenuItem mExit = new JMenuItem("Exit");

                /*try
                {
                    BufferedReader br = new BufferedReader(new FileReader("1.txt"));
                    line  = br.readLine();

                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }*/
                JLabel jUser = new JLabel("User is: " );

                mHelp.setOpaque(false);
                mHelp.setForeground(Color.DARK_GRAY);
                mHelp.setFont(new Font("Verdana", Font.PLAIN,12));
                mCredits.setOpaque(false);
                mCredits.setForeground(Color.DARK_GRAY);
                mCredits.setFont(new Font("Verdana", Font.PLAIN,12));
                mExit.setOpaque(false);
                mExit.setForeground(Color.DARK_GRAY);
                mExit.setFont(new Font("Verdana", Font.PLAIN,12));

                mBar.add(mHelp);
                mBar.add(mCredits);
                mBar.add(mExit);
                mBar.add(jUser);
                //mBar.add(line);

                JFrame frame = new JFrame("MYFRAME");
                frame.setJMenuBar(mBar);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
                frame.setResizable(false);
            }
        });
    }

    public class TestPane extends JPanel
    {
        public TestPane()
        {
            setBorder(new EmptyBorder(20, 20, 20, 20));
            setLayout(new GridLayout(3, 3, 60, 60));
            add(makeButton("Account Code"));
            add(makeButton("Unit Details"));
            add(makeButton("Item Details"));
            add(makeButton("Clearing"));
            add(makeButton("Search"));
            add(makeButton("Exit"));
        }

        protected JButton makeButton(String text)
        {
            JButton btn = new JButton(text);
            btn.setFont(new Font("Verdana", Font.PLAIN,18));
            btn.setMargin(new Insets(30, 30, 30, 30));
            btn.setBackground(Color.blue);
            btn.setOpaque(true);
            btn.setBorderPainted(false);
            return btn;
        }
    }
}

我还是个新手，对Java和GUI还是一知半解。我仍在学习它，所以我正在对我的程序进行试错。 我尝试使用 UIManager 或 UILayout，但仍然不适合我，或者我仍然不知道如何使用它。 我真的很想了解更多有关 GUI 和 Java 的知识，请帮助我。任何意见、评论、建议都会被接受并受到高度赞赏。

MyFrame1:

至于我的目标是这种输出，请。看下一张图片。

我的欲望输出:

此外，如果您注意到有一个 bufferedReader，我正在练习读取带有字符串的“1.txt”，并将其作为标签或(仍然不知道)放在菜单栏中...

Answer 1

首先你必须知道这些

JMenuBar:

An implementation of a menu bar. You add JMenu objects to the menu bar to construct a menu.

J菜单:

An implementation of a menu -- a popup window containing JMenuItems that is displayed when the user selects an item on the JMenuBar.

J菜单项:

An implementation of an item in a menu.

---

因此，将您的 JMenuItem 添加到 JMenu，稍后将此 JMenu 添加到 JMenuBar。

---

//creating a menu `Options`
JMenu menu = new JMenu("Options");

//creating menu items 
JMenuItem mHelp = new JMenuItem("Help");
JMenuItem mCredits = new JMenuItem("Credits");
JMenuItem mExit = new JMenuItem("Exit");

//adding all menu items to menu
menu.add(mHelp);
menu.add(mCredits);
menu.add(mExit);

//adding menu to menu bar               
mBar.add(menu);

//aligning label to right corner of window                
mBar.add(Box.createHorizontalGlue());
mBar.add(jUser);//label

---

输出: