作为继这个帖子 https://stackoverflow.com/questions/34593471/why-do-i-need-to-reset-settext-in-a-jlabel-to-prevent-errors/34598241我遇到了导致计算机崩溃的无限循环。或者，嗯，不完全是：它似乎导致 Java 窗口（JFrame）不断获得焦点/无限地图标化和标准化。像这样不要尝试按原样运行代码。该程序不允许您将其关闭，也不能通过任务管理器来关闭它。
我已经给出了一个完整的代码示例，您可以运行它 - 正如通常建议的那样。由于它是实际程序的精简版本，因此某些代码可能看起来多余（尤其是中间的方法）。重要的方法是：最上面的（构造函数）和最后两个。我猜构造函数和/或refresh method.
正如托马斯指出的here https://stackoverflow.com/questions/34593471/why-do-i-need-to-reset-settext-in-a-jlabel-to-prevent-errors/34598241?noredirect=1#comment57008540_34598241，我将构造函数中的所有代码放在 Runnable 块中，但我想我在那里做错了什么。
重要的是，在实际程序中，此类没有 main 方法，但我从另一个类调用该类，如下所示：
if(getInstance() == null) {
initOverview(0);
}
设置最后两个窗口侦听器，以便当用户重新打开窗口时，其内容会更新。
我一直在调查文档 https://docs.oracle.com/javase/tutorial/essential/concurrency/runthread.html，但我不知道我的错误在哪里。我使用 Runnable 示例是否错误？还是因为Window Listener和setExtendedState（保证窗口的“打开”）互相触发？如果是这样，我该如何解决这个问题？
另一个警告：不要执行此代码，它会使您的计算机崩溃
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();
}
}
