将FXML文件加载到JavaFX中的锚窗格时出错

我目前正在开发的程序有一个菜单和一个锚定窗格，用于根据所选菜单项显示内容。在我的程序中，当用户单击菜单项表单菜单栏时，我想将我的fxml文件加载到内容锚定窗格中，该内容锚定窗格再次位于主fxml文件内。我在main.fxml中构建了锚定窗格

 <AnchorPane id="main_panel" layoutY="28.0" prefHeight="700.0" prefWidth="670.0" />

当我运行程序并单击项目菜单时。它显示了几个错误。我的代码有问题吗？谢谢您的关注

Glass detected outstanding Java exception at -[GlassViewDelegate sendJavaMouseEvent:]:src/com/sun/mat/ui/GlassViewDelegate.m:543
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1456)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.control.MenuItem.fire(MenuItem.java:456)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1199)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$6.handle(ContextMenuContent.java:1148)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$6.handle(ContextMenuContent.java:1146)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3369)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3209)
    at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3164)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1582)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2267)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:250)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:173)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:292)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:530)
    at com.sun.glass.ui.View.notifyMouse(View.java:924)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:75)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:279)
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1451)
    ... 36 more
Caused by: java.lang.NullPointerException
    at project.MainController.go_item(MainController.java:45)
    ... 46 more

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您在FXML中使用的关键字不正确<代码>id被分配给控件，以便它们可以在样式表中引用。您需要使用

fx:id

，以便能够在控制器中引用它，使用通过

@FXML

注释的变量

正确的方法：

<AnchorPane fx:id="main_panel" 
                 layoutY="28.0" prefHeight="700.0" prefWidth="670.0" />

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在MainController的第45行有什么？main_panel.getChildren（）.setAll（仪表板）；非常感谢你的回答。很有效。你的回答对我帮助很大。现在，我知道id和fx:id的区别了。
<AnchorPane fx:id="main_panel" 
                 layoutY="28.0" prefHeight="700.0" prefWidth="670.0" />