java - 获取java.lang.IllegalStateException : This call must happen in the AWT Event Dispatch Thread! 请引用

Question

我正在尝试使用 Swing 实现 Web 浏览器。下面是代码。

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.Insets;

import javax.swing.JPanel;
import javax.swing.JScrollPane;

import chrriis.dj.nativeswing.swtimpl.NativeInterface;
import chrriis.dj.nativeswing.swtimpl.components.JWebBrowser;


public class WebPageDisplay extends JPanel{

    public WebPageDisplay() {

         super(new BorderLayout());  
         try{
         NativeInterface.open();

        JPanel webBrowserPanel = new JPanel(new BorderLayout());   
        final JWebBrowser webBrowser = new JWebBrowser();
        webBrowser.setBarsVisible(false);   
        webBrowser.setStatusBarVisible(true);   
        webBrowserPanel.add(webBrowser, BorderLayout.CENTER);   
        add(webBrowserPanel, BorderLayout.CENTER);
            webBrowser.navigate("www.google.com);
        JScrollPane scrollPane = new JScrollPane();
            Dimension preferredSize = scrollPane.getPreferredSize();
        preferredSize.height += 20;
        scrollPane.setPreferredSize(preferredSize);
        add(scrollPane,new GridBagConstraints(0, 2, 2, 1, 1.0, 1.0, GridBagConstraints.CENTER,
            GridBagConstraints.BOTH, new Insets(0, 0, 0, 0), 0, 0));
           }catch(Exception e){
        e.printStackTrace();
        }
      }

    public static void main(String[] args){
        WebPageDisplay display = new WebPageDisplay();

    }
}

我遇到了异常。

 On Mac, "NativeInterface.initialize()"/"NativeInterface.open()" should not be called after AWT static initializers have run, otherwise there can be all sorts of side effects (non-functional modal dialogs, etc.). Generally, the problem is when the "main(String[])" method is located inside an AWT component subclass and the fix is to move that main method to a standalone class. The problematic class here is "WebPageDisplay"
    ***WARNING: Display must be created on main thread due to Cocoa restrictions.
    2012-09-17 22:48:04.943 java[248:407] _createMenuRef called with existing principal MenuRef already associated with menu
    2012-09-17 22:48:05.134 java[248:407] (
        0   CoreFoundation                      0x00007fff96568286 __exceptionPreprocess + 198
        1   libobjc.A.dylib                     0x00007fff9244dd5e objc_exception_throw + 43
        2   CoreFoundation                      0x00007fff965680ba +[NSException raise:format:arguments:] + 106
        3   CoreFoundation                      0x00007fff96568044 +[NSException raise:format:] + 116
        4   AppKit                              0x00007fff8fea7597 -[NSCarbonMenuImpl _createMenuRef] + 64
        5   AppKit                              0x00007fff8fea6e82 -[NSCarbonMenuImpl _instantiateCarbonMenu] + 148
        6   AppKit                              0x00007fff8fe7bb43 -[NSApplication finishLaunching] + 878
        7   libawt.jnilib                       0x0000000106a6a157 -[NSApplicationAWT finishLaunching] + 641
        8   libswt-pi-cocoa-3730.jnilib         0x00000001080f9eb2 Java_org_eclipse_swt_internal_cocoa_OS_objc_1msgSendSuper__Lorg_eclipse_swt_internal_cocoa_objc_1super_2J + 89
        9   ???                                 0x0000000102abdd6e 0x0 + 4339785070
    )
    java.lang.IllegalStateException: This call must happen in the AWT Event Dispatch Thread! Please refer to http://java.sun.com/docs/books/tutorial/uiswing/concurrency/index.html and http://java.sun.com/javase/6/docs/api/javax/swing/SwingUtilities.html#invokeLater(java.lang.Runnable)
        at chrriis.dj.nativeswing.swtimpl.core.MessagingInterface.checkUIThread(MessagingInterface.java:161)
        at chrriis.dj.nativeswing.swtimpl.core.SWTNativeInterface.checkUIThread(SWTNativeInterface.java:475)
        at chrriis.dj.nativeswing.swtimpl.core.SWTNativeComponent.runSync(SWTNativeComponent.java:184)
        at chrriis.dj.nativeswing.swtimpl.components.core.NativeWebBrowser.navigate(NativeWebBrowser.java:728)
        at chrriis.dj.nativeswing.swtimpl.components.JWebBrowser.navigate(JWebBrowser.java:315)
        at chrriis.dj.nativeswing.swtimpl.components.JWebBrowser.navigate(JWebBrowser.java:305)
        at WebPageDisplay.<init>(WebPageDisplay.java:31)
        at WebPageDisplay.main(WebPageDisplay.java:54)

我在类路径中使用以下 jar。

DJNativeSwing-SWT.jar
DJNativeSwing.jar
swt-3.7M7-cocoa-macosx-x86_64.jar

Answer 1

您的错误消息告诉您出了什么问题:

On Mac, "NativeInterface.initialize()"/"NativeInterface.open()" should not be called after AWT static initializers have run, otherwise there can be all sorts of side effects (non-functional modal dialogs, etc.). Generally, the problem is when the "main(String[])" method is located inside an AWT component subclass and the fix is to move that main method to a standalone class. The problematic class here is "WebPageDisplay"

您需要在事件调度线程(EDT)上启动 GUI。但话虽如此，在 GUI 在 EDT 上排队之前，NativeInterface 需要在 主 线程而不是 EDT 上启动。根据 NativeInterface API 的 open() 方法部分:

Initialization takes place if the interface was not already initialized. If initialization was not explicitely performed, this method should be called early in the program, the best place being as the first call in the main method.

所以你的代码可能如下所示:

public static void main(String[] args){

    // start your NativeInterface here!
    NativeInterface.open(); // not sure what else may be needed for this

    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        WebPageDisplay display = new WebPageDisplay();
      }
    });
}

请注意，我没有也没有使用过 NativeInterface 库，因此无法测试此代码。

请注意，我没有看到您将 GUI 组件添加到顶级窗口(例如 JFrame)的位置，因此我不确定您如何显示 GUI。