小编use*_*231的帖子

我需要在 Eclipse 编辑器中获取活动页面。当我用谷歌搜索时，我发现了下面的代码\xe2\x80\x8b：

IWorkbench wb = PlatformUI.getWorkbench();\nIWorkbenchWindow win = wb.getActiveWorkbenchWindow();\nIWorkbenchPage page = win.getActivePage();\nITextEditor editor = (ITextEditor) page.getActiveEditor();\n

但是，当我使用此代码时，它会生成以下错误消息：

java.lang.NullPointerException\n    at kr.ac.jbnu.ssel.instantfeedback.views.InstantFeedbackView$1.elementChanged(InstantFeedbackView.java:136)\n    at org.eclipse.jdt.internal.core.DeltaProcessor$3.run(DeltaProcessor.java:1662)\n    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)\n    at org.eclipse.jdt.internal.core.DeltaProcessor.notifyListeners(DeltaProcessor.java:1652)\n    at org.eclipse.jdt.internal.core.DeltaProcessor.fireReconcileDelta(DeltaProcessor.java:1504)\n    at org.eclipse.jdt.internal.core.DeltaProcessor.fire(DeltaProcessor.java:1463)\n    at org.eclipse.jdt.internal.core.JavaModelOperation.run(JavaModelOperation.java:765)\n    at org.eclipse.jdt.internal.core.JavaModelOperation.runOperation(JavaModelOperation.java:790)\n    at org.eclipse.jdt.internal.core.CompilationUnit.reconcile(CompilationUnit.java:1250)\n    at org.eclipse.jdt.internal.ui.text.java.JavaReconcilingStrategy.reconcile(JavaReconcilingStrategy.java:128)\n    at org.eclipse.jdt.internal.ui.text.java.JavaReconcilingStrategy.access$0(JavaReconcilingStrategy.java:110)\n    at org.eclipse.jdt.internal.ui.text.java.JavaReconcilingStrategy$1.run(JavaReconcilingStrategy.java:90)\n    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)\n    at org.eclipse.jdt.internal.ui.text.java.JavaReconcilingStrategy.reconcile(JavaReconcilingStrategy.java:87)\n    at org.eclipse.jdt.internal.ui.text.java.JavaReconcilingStrategy.reconcile(JavaReconcilingStrategy.java:154)\n    at org.eclipse.jdt.internal.ui.text.CompositeReconcilingStrategy.reconcile(CompositeReconcilingStrategy.java:89)\n    at org.eclipse.jdt.internal.ui.text.JavaCompositeReconcilingStrategy.reconcile(JavaCompositeReconcilingStrategy.java:104)\n    at org.eclipse.jface.text.reconciler.MonoReconciler.process(MonoReconciler.java:73)\n    at org.eclipse.jface.text.reconciler.AbstractReconciler$BackgroundThread.run(AbstractReconciler.java:207)\n

我该如何解决这个问题？

添加\n这是我的 elementChanged() 函数。它在方法中。

private void addListenerToCheckChange_save() {\n  JavaCore.addElementChangedListener(new IElementChangedListener() {\n\n    @Override\n    public void elementChanged(ElementChangedEvent event) …