最大化 JFrame 的动作？

Question

有谁知道一旦发生特定操作如何最大化 JFrame ？我将在下面发布我的代码，我是一个不评论我的代码的恶魔（我会在某个时候这样做），但它应该是相当不言自明的。我想做的是从菜单中选择选项后使框架最大化。如果有人能告诉我如何编辑代码才能实现这一目标，我将不胜感激。

谢谢！

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.ButtonGroup;
import javax.swing.JMenuBar;
import javax.swing.KeyStroke;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.JFrame;

public class MainMenu implements ActionListener {
    JTextArea output;
    JScrollPane scrollPane;
    String newline = "\n";
    MapMenu maps = new MapMenu();

public JMenuBar createMenuBar() {
    JMenuBar menuBar;
    JMenu menu;
    JMenuItem menuItem;
    JMenuItem minOption, maxOption;

    //Create the menu bar.
    menuBar = new JMenuBar();

    //Build the first menu.
    menu = new JMenu("File");
    menu.setMnemonic(KeyEvent.VK_A);
    menu.getAccessibleContext().setAccessibleDescription("For window operations");
    menuBar.add(menu);

    minOption = new JMenuItem("Minimize", KeyEvent.VK_T);
    minOption.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_1, ActionEvent.ALT_MASK));
    minOption.getAccessibleContext().setAccessibleDescription("Will minimize window");
    minOption.setActionCommand("Minimize");
    minOption.addActionListener(this);
    menu.add(minOption);

    maxOption = new JMenuItem("Maximize", KeyEvent.VK_T);
    maxOption.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_2, ActionEvent.ALT_MASK));
    maxOption.getAccessibleContext().setAccessibleDescription("Will maximize window");
    maxOption.setActionCommand("Maximize");
    maxOption.addActionListener(this);
    menu.add(maxOption);

    menuItem = new JMenuItem("Exit", KeyEvent.VK_T);
    menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_3, ActionEvent.ALT_MASK));
    menuItem.getAccessibleContext().setAccessibleDescription("Will close window");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    //Build second menu in the menu bar.
    menu = new JMenu("Pages");
    menu.setMnemonic(KeyEvent.VK_N);
    menu.getAccessibleContext().setAccessibleDescription("For accessing other pages");
    menuBar.add(menu);

    menuItem = new JMenuItem("Date Calculator", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens date calculator");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    menuItem = new JMenuItem("Maps", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens popular maps");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    menuItem = new JMenuItem("Points System", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens points chart");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    menuItem = new JMenuItem("Foreign Language Re-targets", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens LPS Lists");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    //Build third menu in the menu bar.
    menu = new JMenu("Resources");
    menu.setMnemonic(KeyEvent.VK_N);
    menu.getAccessibleContext().setAccessibleDescription("For external resources");
    menuBar.add(menu);

    menuItem = new JMenuItem("Helpful Sites", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens website links");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    //Build fourth menu in the menu bar.
    menu = new JMenu("Help");
    menu.setMnemonic(KeyEvent.VK_N);
    menu.getAccessibleContext().setAccessibleDescription("For help pages");
    menuBar.add(menu);

    menuItem = new JMenuItem("How To Use", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens tutorial for AAA");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    menuItem = new JMenuItem("About", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens information about AAA");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    menuItem = new JMenuItem("Update", KeyEvent.VK_T);
    menuItem.getAccessibleContext().setAccessibleDescription("Opens website for AAA");
    menuItem.addActionListener(this);
    menu.add(menuItem);

    return menuBar;
}

public Container createContentPane() {
    //Create the content-pane-to-be.
    JPanel contentPane = new JPanel(new BorderLayout());
    contentPane.setOpaque(true);

    //Create a scrolled text area.
    output = new JTextArea(5, 30);
    output.setEditable(false);
    scrollPane = new JScrollPane(output);

    //Add the text area to the content pane.
    contentPane.add(scrollPane, BorderLayout.CENTER);

    return contentPane;
}

// Returns just the class name -- no package info.
protected String getClassName(Object o) {
    String classString = o.getClass().getName();
    int dotIndex = classString.lastIndexOf(".");
    return classString.substring(dotIndex+1);
}

/** Returns an ImageIcon, or null if the path was invalid. */
protected static ImageIcon createImageIcon(String path) {
    java.net.URL imgURL = MainMenu.class.getResource(path);
    if (imgURL != null) {
        return new ImageIcon(imgURL);
    } else {
        System.err.println("Couldn't find file: " + path);
        return null;
    }
}

/**
 * Create the GUI and show it.  For thread safety,
 * this method should be invoked from the
 * event-dispatching thread.
 */
private static void createAndShowGUI() {
    //Create and set up the window.
    JFrame.setDefaultLookAndFeelDecorated(false);
    JFrame frame = new JFrame("Account Appeal Aide");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Create and set up the content pane.
    MainMenu demo = new MainMenu();
    frame.setJMenuBar(demo.createMenuBar());
    frame.setContentPane(demo.createContentPane());

    //Display the window.
    frame.setSize(500, 400);
    frame.setVisible(true);
    frame.setResizable(false);

    Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();

    int w = frame.getSize().width;
    int h = frame.getSize().height;
    int x = (dim.width-w)/2; 
    int y = (dim.height-h)/2; 

    frame.setLocation(x, y); 
}

public void maximizeFrame(JFrame aFrame) {
    aFrame.setExtendedState(aFrame.getExtendedState()|JFrame.MAXIMIZED_BOTH);
}

public void actionPerformed(ActionEvent e) {
    if("Minimize".equals(e.getActionCommand())) {
        maps.openMapMenu();
    }
    if("Maximize".equals(e.getActionCommand())) {
        //maximizeFrame();
    }
}

public static void main(String[] args) {
    //Schedule a job for the event-dispatching thread:
    //creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}

}

Answer 1

您不需要包含当前状态；这应该足够了：

aFrame.setExtendedState(JFrame.MAXIMIZED_BOTH);

不过，您需要在 actionPerformed 方法中访问您的框架，因此您应该将其设为私有字段。

在课程开始时，您声明一些字段。这些都应该标记为私有，并且您还应该添加框架。所以它看起来像这样：

public class MainMenu implements ActionListener {
    private JTextArea output;
    private JScrollPane scrollPane;
    private String newline = "\n";
    private MapMenu maps = new MapMenu();
    private JFrame frame;

然后，当你有 JFrame frame = new JFrame("Account Appeal Aide"); 时，只需执行 frame = new JFrame("Account Appeal Aide" ); 改为; frame 已声明。然后，您也可以在 actionPerformed 中使用它：

if("Maximize".equals(e.getActionCommand())) {
    maximizeFrame(frame);
}