Eclipse RCP：调用透视图更改导致堆栈溢出

Question

我有一个 Eclipse RCP 应用程序，我正在从 Eclipse 3.0 迁移到 4.4，它目前运行良好。由于迁移，添加了一些菜单条目（例如通用打开文件），我想将其删除。到目前为止，这是可行的，因为我在我的 perspectiveActivated() 方法中调用了 hideActionset(...)。

菜单项消失。但是当我重置透视图然后更改透视图时，菜单项再次出现。我试图通过在我的 perspectiveChanged(...) 方法中调用 hideActionSet(...) 来解决此问题，但它们被频繁调用以致我得到一个堆栈溢出。

    /**
     * @see org.eclipse.ui.IPerspectiveListener#perspectiveActivated(org.eclipse.ui.IWorkbenchPage, org.eclipse.ui.IPerspectiveDescriptor)
     */
    public void perspectiveActivated(IWorkbenchPage page, IPerspectiveDescriptor perspective) 
    {
        if( perspective.getId().equals(m_PerspektivenID) || m_PerspektivenID.equals(STANDARDAKTION))
        {
            setEnabled( true );
        }
        else
        {
            setEnabled( false );
        }

        if(page != null)
        {
            page.hideActionSet("org.eclipse.ui.actionSet.keyBindings");
            page.hideActionSet("org.eclipse.ui.actionSet.openFiles");
        }
    }

    /**
     * @see org.eclipse.ui.IPerspectiveListener#perspectiveChanged(org.eclipse.ui.IWorkbenchPage, org.eclipse.ui.IPerspectiveDescriptor, java.lang.String)
     */
    public void perspectiveChanged(IWorkbenchPage page, IPerspectiveDescriptor perspective, String changeId) 
    {
        if(page != null)
        {
            page.hideActionSet("org.eclipse.ui.actionSet.keyBindings");
            page.hideActionSet("org.eclipse.ui.actionSet.openFiles");
        }
    }

这是正在生成的两个日志文件之一的片段：

!ENTRY org.eclipse.equinox.event 4 0 2016-01-12 14:37:00.768
!MESSAGE Exception while dispatching event org.osgi.service.event.Event [topic=org/eclipse/e4/ui/model/ui/UIElement/widget/SET] to handler org.eclipse.e4.ui.services.internal.events.UIEventHandler@faec277
!STACK 0
java.lang.StackOverflowError
    at java.util.HashMap.hash(HashMap.java:338)
    at java.util.HashMap.containsKey(HashMap.java:595)
    at java.util.Collections$SynchronizedMap.containsKey(Collections.java:2578)
    at org.eclipse.e4.core.internal.contexts.EclipseContext.set(EclipseContext.java:347)
    at org.eclipse.e4.ui.internal.services.ContextContextService.setEventCaching(ContextContextService.java:129)
    at org.eclipse.e4.ui.internal.services.ContextContextService.deferUpdates(ContextContextService.java:86)
    at org.eclipse.ui.internal.contexts.ContextService.deferUpdates(ContextService.java:92)
    at org.eclipse.ui.internal.Perspective.removeActionSet(Perspective.java:362)
    at org.eclipse.ui.internal.WorkbenchPage.hideActionSet(WorkbenchPage.java:2593)
    at packagenane.classname.perspectiveChanged(BaseAction.java:146)
    at org.eclipse.ui.internal.PerspectiveListenerList$4.run(PerspectiveListenerList.java:134)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.core.runtime.Platform.run(Platform.java:867)
    at org.eclipse.ui.internal.PerspectiveListenerList.fireEvent(PerspectiveListenerList.java:58)
    at org.eclipse.ui.internal.PerspectiveListenerList.firePerspectiveChanged(PerspectiveListenerList.java:131)
    at org.eclipse.ui.internal.WorkbenchWindow.firePerspectiveChanged(WorkbenchWindow.java:1721)
    at org.eclipse.ui.internal.WorkbenchPage.hideActionSet(WorkbenchPage.java:2596)
    at packagenane.classname.perspectiveChanged(BaseAction.java:146)
    at org.eclipse.ui.internal.PerspectiveListenerList$4.run(PerspectiveListenerList.java:134)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.core.runtime.Platform.run(Platform.java:867)
    at org.eclipse.ui.internal.PerspectiveListenerList.fireEvent(PerspectiveListenerList.java:58)
    at org.eclipse.ui.internal.PerspectiveListenerList.firePerspectiveChanged(PerspectiveListenerList.java:131)
    at org.eclipse.ui.internal.WorkbenchWindow.firePerspectiveChanged(WorkbenchWindow.java:1721)
    at org.eclipse.ui.internal.WorkbenchPage.hideActionSet(WorkbenchPage.java:2596)
    at packagenane.classname.perspectiveChanged(BaseAction.java:146)
    at org.eclipse.ui.internal.PerspectiveListenerList$4.run(PerspectiveListenerList.java:134)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.core.runtime.Platform.run(Platform.java:867)
    at org.eclipse.ui.internal.PerspectiveListenerList.fireEvent(PerspectiveListenerList.java:58)
    at org.eclipse.ui.internal.PerspectiveListenerList.firePerspectiveChanged(PerspectiveListenerList.java:131)
    at org.eclipse.ui.internal.WorkbenchWindow.firePerspectiveChanged(WorkbenchWindow.java:1721)
    at org.eclipse.ui.internal.WorkbenchPage.hideActionSet(WorkbenchPage.java:2596)
    at packagenane.classname.perspectiveChanged(BaseAction.java:146)
    at org.eclipse.ui.internal.PerspectiveListenerList$4.run(PerspectiveListenerList.java:134)

Answer 1

如果您查看堆栈跟踪，您可以清楚地看到，当您调用 WorkbenchPage.hideActionSet 时，会触发一个新的视角更改事件，并且在您仍在第一次调用 perspectiveChanged 时再次调用 perspectiveChanged。

阻止这种情况的一种方法是在您的 perspectiveChanged 方法中添加一个标志，以检测您已经在处理更改。

类似：

private boolean changeActive;

public void perspectiveChanged(IWorkbenchPage page, IPerspectiveDescriptor perspective, String changeId) 
{
  if (changeActive) {   // Don't do anything if already handling change
    return;
  }

  changeActive = true;

  if (page != null)
    {
        page.hideActionSet("org.eclipse.ui.actionSet.keyBindings");
        page.hideActionSet("org.eclipse.ui.actionSet.openFiles");
    }

  changeActive = false;
}