如果从另一个 JFrame 类调用该类，则无法打开 JFrame答案

【问题标题】：Trouble with opening JFrames if the class is being called from another JFrame class如果从另一个 JFrame 类调用该类，则无法打开 JFrame
【发布时间】：2012-05-15 15:31:34
【问题描述】：

我正在制作Talisman Game，到目前为止，我有创建Random Characters 和WIP Main Menu 的方法。现在，如果我从主类调用新游戏（创建角色）方法，一切都很好，但如果我从主手册中调用它，JFrame 会变得透明并复制它们的背景（就像窗口卡住时一样）

新的游戏方式是：

public Game(int playerNum) {

    for (int i = 0; i < chars.length; i++)
    chars[i] = false;

    this.playerNum=playerNum;

    players = new Player[playerNum];
    guiChars = new Gui_Chars[playerNum];

    Card.createCards();
    Game.randomChar();
    for (int j = 0; j < playerNum; j++)
        guiChars[j].update();
}

现在，游戏，randomChar() 创建角色：

public static void randomChar() {
    for (int i = 0; i < playerNum; i++) {
        do {
            chooseChar = rnd.nextInt(14);
        } while (chars[chooseChar]);
        switch (chooseChar) {
            case 0: {
                players[i] = new Char_ASSASIN();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                + "Assasin", players[i], "Images/assassin.jpg");
                System.out.println("Player " + (i + 1) + " is an Assasin");
                chars[0] = true;
                break;
            }
            case 1: {
                players[i] = new Char_DRUID();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                    + "Druid", players[i], "Images/druid.jpg");
                System.out.println("Player " + (i + 1) + " is a Druid");
                chars[1] = true;
                break;
            }
            case 2: {
                players[i] = new Char_DWARF();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                   + "Dwarf", players[i], "Images/dwarf.jpg");
                System.out.println("Player " + (i + 1) + " is a Dwarf");
                chars[2] = true;
                break;
            }
            case 3: {
                players[i] = new Char_ELF();
                guiChars[i] = new Gui_Chars(
                         "Player " + (i + 1) + " - " + "Elf", players[i],
                                                           "Images/elf.jpg");
                System.out.println("Player " + (i + 1) + " is an Elf");
                chars[3] = true;
                break;
            }
            case 4: {
                players[i] = new Char_GHOUL();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                  + "Ghoul", players[i], "Images/ghoul.jpg");
                System.out.println("Player " + (i + 1) + " is a Ghoul");
                chars[4] = true;
                break;
            }
            case 5: {
                players[i] = new Char_MINSTREL();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                            + "Minesrel", players[i], "Images/minstrel.jpg");
                System.out.println("Player " + (i + 1) + " is a Minstrel");
                chars[5] = true;
                break;
            }
            case 6: {
                players[i] = new Char_MONK();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                    + "Monk", players[i], "Images/monk.jpg");
                System.out.println("Player " + (i + 1) + " is a Monk");
                chars[6] = true;
                break;
            }
            case 7: {
                players[i] = new Char_PRIEST();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                + "Priest", players[i], "Images/priest.jpg");
                System.out.println("Player " + (i + 1) + " is a Priest");
                chars[7] = true;
                break;
            }
            case 8: {
                players[i] = new Char_PROPHETESS();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                        + "Prophetess", players[i], "Images/prophetess.jpg");
                System.out.println("Player " + (i + 1) + " is a Prophetess");
                chars[8] = true;
                break;
            }
            case 9: {
                players[i] = new Char_SORCERESS();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                          + "Sorceress", players[i], "Images/sorceress.jpg");
                System.out.println("Player " + (i + 1) + " is a Sorceress");
                chars[9] = true;
                break;
            }
            case 10: {
                players[i] = new Char_THIEF();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                  + "Thief", players[i], "Images/thief.jpg");
                System.out.println("Player " + (i + 1) + " is a Thief");
                chars[10] = true;
                break;
            }
            case 11: {
                players[i] = new Char_TROLL();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                  + "Troll", players[i], "Images/troll.jpg");
                System.out.println("Player " + (i + 1) + " is a Troll");
                chars[11] = true;
                break;
            }
            case 12: {
                players[i] = new Char_WARRIOR();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                              + "Warrior", players[i], "Images/warrior.jpg");
                System.out.println("Player " + (i + 1) + " is a Warrior");
                chars[12] = true;
                break;
            }
            case 13: {
                players[i] = new Char_WIZARD();
                guiChars[i] = new Gui_Chars("Player " + (i + 1) + " - "
                                + "Wizard", players[i], "Images/wizard.jpg");
                System.out.println("Player " + (i + 1) + " is a Wizard");
                chars[13] = true;
                break;
            }
        }
    }
}

角色调用 GUI（从 Characters 类接收信息，但这肯定不是问题）：

public Gui_Chars(String character,Player player,String path) {

    super(character);
    setVisible(true);
    setSize(430, 420);

    setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
    revalidate();
}

我删除了代码中不重要的部分，没有它也会出现问题...... 最后，这是MainMenu：

public class MainMenu extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    JLabel num;
    JButton add, sub, start;
    private int i = 2;
    JFrame j ;
    Game game;

    JLayeredPane jp1,jp2,jp3;

    public MainMenu() {

        j= new JFrame("Talisman");
        j.setVisible(true);
        j.setSize(300, 300);
        j.setDefaultCloseOperation(EXIT_ON_CLOSE);

        jp1 = new JLayeredPane();
        jp2 = new JLayeredPane();
        jp3 = new JLayeredPane();   

        JPanel playerNum = new JPanel(new GridBagLayout());
        JPanel startPanel = new JPanel(new GridBagLayout());

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(30, 30, 30, 30);

        add = new JButton("+1");
        sub = new JButton("-1");
        start = new JButton("Start");

        start.setPreferredSize(new Dimension(100, 100));

        num = new JLabel("" + i);
        num.setFont(new Font("Serif", Font.BOLD, 40));

        gbc.gridy = 0;
        playerNum.add(add, gbc);
        add.addActionListener(this);
        add.setActionCommand("add");

        gbc.gridy = 1;
        playerNum.add(num, gbc);

        gbc.gridy = 2;
        playerNum.add(sub, gbc);
        sub.addActionListener(this);
        sub.setActionCommand("sub");

        startPanel.add(start, gbc);
        start.addActionListener(this);
        start.setActionCommand("start");

        jp1.add(new ContentPanel());
        jp2.add(playerNum);
        jp3.add(startPanel);

        jp1.setLayer(new ContentPanel(), 1);
        jp2.setLayer(playerNum, 2);
        jp3.setLayer(startPanel, 2);

        j.add(playerNum, BorderLayout.WEST);
        j.add(startPanel, BorderLayout.EAST);

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String act = e.getActionCommand();

        if (act.equals("start")) {
            j.setVisible(false);
            j.dispose();
            game = new Game(i);
            game.startGame();

            //JFrame j = new JFrame();
            //j.setVisible(true);
            //j.setSize(300, 300);
        }
    }
}

很抱歉代码太长了，但我在调试过程中尝试了几个小时都没有找到问题所在。如果有人能帮助我了解发生了什么，我将非常感激...... 再次感谢，抱歉代码太长了...

【问题讨论】：

据我所知，据我了解，当您重新启动时，您似乎已经处理了您的JLayer，但您忘记将它们从上述JFrame 中删除，所以每次您调用startGame() 函数，它不断在前一个控件之上添加控件，因此您得到了效果。而是在startGame() 方法的开头添加frame.removeAll()，或者在调用startGame() 之前在actionPerformed(...) 方法中执行此操作，这可能可以解决问题，我猜:-)
JLayers 只是我尝试过的东西，我并没有真正将它们付诸实践，而且问题也发生在它们之前......我厌倦了 removeAll() 并且仍然是相同的结果。感谢您的帮助，还有什么想法吗？
很抱歉，在没有工作代码的情况下，有时很难说出原因:(哦，你正在处理你正在处理的当前JFrame，在你的actionPerformed()方法中,是不是你需要改变那部分，做一些有意义的事情。或者也试试这个，在写完dispose()之后，再次调用你的MainMenu()类的构造函数，这可能会开始一个新的JFrame 我猜。
但是，如果我从主类调用完全相同的类，而不是从主手册中调用它，是否有逻辑？
见The Use of Multiple JFrames, Good/Bad Practice?

标签： java swing user-interface jframe

【解决方案1】：

通过查看您的代码，我认为您不了解 Swings 绘制子系统。

最重要的一点是，永远不要在 Swing 的事件调度事件 (ETD) 中执行任何长时间或阻塞操作。

当您在 Main 中调用它时它起作用的原因实际上是侥幸。 Java 不保证哪个线程将执行 Main 方法。你很幸运，这不是 ETD。启动 Swing 应用程序时，您必须始终执行以下操作

EventQueue.invokeLater(new Runnable() {
    public void run() {
        // Your launch code here
    }
}

显然，只在其中包含与 UI 相关的代码。

它现在不起作用的原因是您正在从您的动作侦听器中执行一段阻塞代码，这会阻止 ETD 更新屏幕。

for (int i = 0; i < chars.length; i++)
    chars[i] = false;

.
.
.

public static void randomChar() {
    for (int i = 0; i < playerNum; i++) {
        do {
            chooseChar = rnd.nextInt(14);
        } while (chars[chooseChar]); // This is never true...

从哪里调用

game = new Game(i);

您需要更改您的游戏模型，以允许从除 ETD 之外的线程上下文调用“randomChar”方法。我建议（为方便起见），比如 SwingWoker (http://docs.oracle.com/javase/tutorial/uiswing/concurrency/worker.html)

从您的代码示例中，我看不到“chars[x]”在哪里设置为 true...

实际上，您可能想阅读整个Concurrency in Swing 教程...

【讨论】：