java - JOptionPane 给出错误

Question

我想使用 JOptionPane 处理一些异常。这是主要方法:

public class MainRun {

public static void main(String args[]){    
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                UIManager.setLookAndFeel(new SubstanceRavenGraphiteGlassLookAndFeel());
            }catch (Exception e){
                e.printStackTrace();
            }                 
            new MainGui().setVisible(true);                
            new Initialized().start();
            new PriorityMessageQueue().start();
        }
    });

MainGui 是应用程序的主窗口 (JFrame)。我在 PriorityMessageQueue 线程内处理了异常。

public class PriorityMessageQueue extends Thread {

@Override
public void run() {

    while (true) {
        try {
            instantMessages = instant.getMobitelMessagesToBeSent();
        } catch (Exception ex) {
                        JOptionPane.showMessageDialog(
                        null,
                        ex.getMessage(),
                        "Database Error",
                        JOptionPane.ERROR_MESSAGE);

        }

        ...

运行此命令后，出现错误

   org.jvnet.substance.api.UiThreadingViolationException: Component creation must be done on Event Dispatch Thread
at org.jvnet.substance.utils.SubstanceCoreUtilities.testComponentCreationThreadingViolation(SubstanceCoreUtilities.java:2312)
at org.jvnet.substance.SubstanceOptionPaneUI.createUI(SubstanceOptionPaneUI.java:83)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:37)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:244)
at javax.swing.UIDefaults.getUI(UIDefaults.java:752)
at javax.swing.UIManager.getUI(UIManager.java:989)
at javax.swing.JOptionPane.updateUI(JOptionPane.java:1859)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1822)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1785)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1753)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1731)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1711)
at GUI.MainGui.showOptionPane(MainGui.java:1039)
at SMS.PriorityMessageQueue.run(PriorityMessageQueue.java:86)
    UIDefaults.getUI() failed: createUI() failed for
      javax.swing.JOptionPane
   [,0,0,0x0,invalid,alignmentX=0.0,alignmentY=0.0,border=,flags=0,maximumSize=,minimumSize=,p
   referredSize=,icon=,initialValue=,message=DatabaseConnection class
   connect,messageType=ERROR_MESSAGE,optionType=DEFAULT_OPTION,wantsInput=false]
   java.lang.reflect.InvocationTargetException
   java.lang.Error
at javax.swing.UIDefaults.getUIError(UIDefaults.java:712)
at javax.swing.MultiUIDefaults.getUIError(MultiUIDefaults.java:133)
at javax.swing.UIDefaults.getUI(UIDefaults.java:758)
at javax.swing.UIManager.getUI(UIManager.java:989)
at javax.swing.JOptionPane.updateUI(JOptionPane.java:1859)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1822)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1785)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1753)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1731)
at javax.swing.JOptionPane.<init>(JOptionPane.java:1711)
at GUI.MainGui.showOptionPane(MainGui.java:1039)
at SMS.PriorityMessageQueue.run(PriorityMessageQueue.java:86)

并且 JOptionPane 将无法正确显示!

如何获取parentComponent (MainGui JFrame)，而不是将null传递给JOptionPane？/p>

Answer 1

JOptionPane 是一个迷你 Swing GUI，与所有 Swing GUI 一样，它必须在 Swing 事件线程上创建，而不是在后台线程上创建。这可以通过在 Runnable 中创建 JOptionPane，然后在事件线程上对 Runnable 进行排队来完成:

SwingUtilities.invokeLater(new Runnable() {
  public void run() {
    JOptionPane.showMessageDialog(....);
  }
});

例如，

} catch (Exception ex) {
   final String exMessage = ex.getMessage();

   SwingUtilities.invokeLater(new Runnable() {
     public void run() {
       JOptionPane.showMessageDialog(
         null,
         exMessage,
         "Database Error",
         JOptionPane.ERROR_MESSAGE);
       );
     }
   });
  }
}

关于你的问题，

Instead of passing null to JOptionPane, how can I get the parentComponent (MainGui JFrame)?

您需要主 GUI 的引用。如何获得此信息取决于您的程序的组织方式。