小编典典

JFrame Java中的无限消失重现循环

java

作为继承这个帖子我运行到一个无限循环,导致我的电脑死机。或者,不是很好:它似乎导致Java窗口(JFrame)不断获得焦点/获得图标化和无限地规范化。因此,
请勿尝试按原样运行代码 。该程序不允许您关闭它,也不能通过任务管理器关闭它。

我已经给出了一个完整的代码示例,您可以运行它-
正如通常所建议的那样。由于它是实际程序的简化版本,因此某些代码似乎是多余的(尤其是中间的方法)。重要的方法是:最顶层的(构造函数)和最后两个。我猜构造器和/或refresh方法出了问题。

正如托马斯指出,在这里,我把所有的代码在构造函数中的一个Runnable块,但我想我做错了那里。

重要的是,在实际程序中,此类没有main方法,但是我从另一个Class调用了Class,如下所示:

if(getInstance() == null) {
    initOverview(0);
}

设置最后两个窗口侦听器,以便在用户重新打开窗口时更新其内容。

我一直在研究文档,但是我不知道我的错误在哪里。我使用Runnable示例错误吗?还是由于窗口侦听器和setExtendedState(以确保窗口的“打开”)相互触发?如果是这样,我该如何解决?

另一个警告:请勿执行此代码,否则将使您的计算机掉线

import javax.swing.*;
import java.awt.Color;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.lang.reflect.InvocationTargetException;
import java.awt.BorderLayout;
import java.awt.GridLayout;

public class OverviewTest extends JFrame {

    private static final long serialVersionUID = 1L;
    private static OverviewTest instance = null;

    private static JLabel labelTextOverview;
    private static JTabbedPane tabbedPane;
    private static JPanel mapPane;

    private OverviewTest() {
        try {
            SwingUtilities.invokeAndWait(new Runnable() {
                public void run() {
                    setTitle("Game - Overview");
                    setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
                    setResizable(true);
                    setBounds(100, 100, 960, 720);

                    JPanel contentPane = new JPanel();
                    setContentPane(contentPane);
                    contentPane.setLayout(new BorderLayout(0, 0));

                    tabbedPane = new JTabbedPane(JTabbedPane.TOP);

                    contentPane.add(tabbedPane);

                    /* TAB 1: Entity Overview */
                    labelTextOverview = new JLabel();
                    labelTextOverview.setText(entityOverviewHTML());

                    JScrollPane scrollPaneEntityOverview = new JScrollPane(labelTextOverview);

                    tabbedPane.addTab("Entity overview", null, scrollPaneEntityOverview, null);

                    /* TAB 2: Map */
                    mapPane = new JPanel();
                    mapPane.setLayout(new GridLayout(6, 6, 2, 2));
                    fillMap();

                    tabbedPane.addTab("Map", null, mapPane, null);

                    /* TAB 3: Rules */
                    JLabel labelRules = new JLabel();
                    labelRules.setText(rulesHTML());

                    JScrollPane scrollPaneRules = new JScrollPane(labelRules);

                    tabbedPane.addTab("Rules", null, scrollPaneRules, null);

                    // Immediately show window on creation 
                    setVisible(true);
                    setExtendedState(JFrame.ICONIFIED);
                    setExtendedState(JFrame.NORMAL);

                    // Add window listener so that contents get refreshed on window active/focus
                    addWindowListener(new WindowAdapter() {
                        @Override
                        public void windowClosing(WindowEvent e) {
                            setVisible(false);
                        }
                        @Override
                        public void windowActivated(WindowEvent e){
                            refresh(tabbedPane.getSelectedIndex());
                        }
                        @Override
                        public void windowDeiconified(WindowEvent e){
                            refresh(tabbedPane.getSelectedIndex());
                        }
                    });
                }
            });
        } catch (InvocationTargetException | InterruptedException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        if(getInstance() == null) {
            initOverview(0);
        }
    }
    private String rulesHTML() {
        StringBuilder sbRules = new StringBuilder();

        sbRules.append("<html><body style='padding: 12px;'>");

        sbRules.append("<h2>Some text for Rules</h2>");
        sbRules.append("<h3>Lorem ipsum</h3>");

        sbRules.append("</body></html>");

        return sbRules.toString();
    }

    private static void fillMap() {
        mapPane.removeAll();
        for (int i = 0; i < 36; i++) {
            JLabel textTile = new JLabel(fillTile(i));
            JScrollPane tile = new JScrollPane(textTile);

            tile.setBorder(BorderFactory.createLineBorder(Color.BLACK));
            mapPane.add(tile);
        }
    }
    private static String fillTile(int i) {
        StringBuilder sbTile = new StringBuilder();

        sbTile.append("<html>");
        sbTile.append("some text");
        sbTile.append("</html>");

        return sbTile.toString();
    }

    /**
     * Reset UI components to system default
     */
    public static void initOverview(int index) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        }
        catch (UnsupportedLookAndFeelException | ClassNotFoundException | InstantiationException | IllegalAccessException e) {
            System.err.println(e);
        }
        instance = new OverviewTest();
        tabbedPane.setSelectedIndex(index);
    }

    public static OverviewTest getInstance() {
        return instance;
    }

    private static String entityOverviewHTML() {
        StringBuilder sb = new StringBuilder();

        sb.append("<html><body style='padding: 12px;'>");

        sb.append("<h2>Some text for Rules</h2>");
        sb.append("<h3>Lorem ipsum</h3>");

        // Normally a loop that runs over getEntityInfo();
        sb.append(getEntityInfo());
        sb.append("</body></html>");

        return sb.toString();
    }

    private static StringBuilder getEntityInfo() {
        StringBuilder sbInfo = new StringBuilder();

        sbInfo.append("this is not a drill, but a test");

        return sbInfo;
    }

    private static void bringToFront() {
        getInstance().setVisible(true);
        getInstance().setExtendedState(JFrame.ICONIFIED);
        getInstance().setExtendedState(JFrame.NORMAL);
    }

    public static void refresh(int index) {
        labelTextOverview.setText(entityOverviewHTML());
        fillMap();
        tabbedPane.setSelectedIndex(index);
        getInstance().repaint();
        bringToFront();
    }
}

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2020-11-30

共1个答案

小编典典

我不确定您为什么同时调用这两种方法

    getInstance().setExtendedState(JFrame.ICONIFIED);
    getInstance().setExtendedState(JFrame.NORMAL);

但是如果您删除第一个,即简单地:

    getInstance().setExtendedState(JFrame.NORMAL);

那么它只打开一次窗口,没有您描述的无限循环。

您的代码导致无限循环的原因是,它使框架最小化然后再最小化,这导致windowActivated方法运行:这调用refresh方法,后者又调用bringToFront方法,使框架最小化和最小化等。


实际将窗口置于最前面,基于这个问题,以下内容对我有用

private static void bringToFront() {                                                             
    getInstance().setVisible(true);                                                              
    getInstance().setExtendedState(JFrame.NORMAL);                                               
    getInstance().toFront();                                                                     
    getInstance().repaint();                                                                     
}
2020-11-30