我希望我能指出正确的方向，因为我缺乏什么知识，这使我无法理解其根本原因。我在名为'IndexFile'的类中有一个try / catch块，我希望catch在我的Controller类中运行一个方法，使窗格可见。强制异常时，catch块会抛出NullPointerException错误，好像有些东西禁止我的IndexFile类执行默认Controller类中的方法。我已经尝试了实例化/创建Controller类的实例以及扩展它，但问题仍然存在。为了澄清，我的问题不是NullPointer的意思，而是为什么Pane为null。当gui被创建时，它是否会被初始化？
我对编程非常陌生，所以请原谅我的任何公然疏忽，他们肯定不是故意的。我试图自己找到这个问题的解决方案，但我找到的信息要么不适用于我的情况，要么对我来说找不到共性。提前感谢您提供的任何建议！
Catch block;目前正在扩展Controller以访问'errorPopup'方法。
catch (Exception e) {
System.out.println(e);
System.out.println("getting this far");
errorPopup("test");
}
errorPopup方法本身位于Controller类中。如果直接从Controller类运行，errorPane.setVisible工作正常，但从IndexFile类调用时则不行。
public void errorPopup(String error) {
errorPane.setVisible(true);
errorPaneText.setText(error);
}
编辑 - IndexFile类本身：
public class IndexFile extends Controller{
public void seasonIndex(int epCount) {
StringBuilder seriesIndex = new StringBuilder();
StringBuilder seriesBreakout = new StringBuilder();
File index = new File("C:\\index.html");
File breakout = new File("C:\\breakout.html");
seriesIndex.append("removed for length");
seriesBreakout.append("removed for length");
BufferedWriter writer;
try {
writer = new BufferedWriter(new FileWriter(index));
writer.append(seriesIndex);
writer.flush();
writer = new BufferedWriter(new FileWriter(breakout));
writer.append(seriesBreakout);
writer.flush();
} catch (Exception e) {
System.out.println(e);
System.out.println("getting this far");
errorPopup("test");
}
}
异常日志：
> Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1787)
at javafx.fxml/javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1670)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8863)
at javafx.controls/com.sun.javafx.scene.control.behavior.TextFieldBehavior.fire(TextFieldBehavior.java:184)
at javafx.controls/com.sun.javafx.scene.control.behavior.TextInputControlBehavior.lambda$keyMapping$62(TextInputControlBehavior.java:330)
at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$KeyHandler.process(Scene.java:4083)
at javafx.graphics/javafx.scene.Scene$KeyHandler.access$1600(Scene.java:4029)
at javafx.graphics/javafx.scene.Scene.processKeyEvent(Scene.java:2146)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2620)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$1(GlassViewEventHandler.java:248)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
at javafx.graphics/com.sun.glass.ui.View.handleKeyEvent(View.java:547)
at javafx.graphics/com.sun.glass.ui.View.notifyKey(View.java:971)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:175)
at java.base/java.lang.Thread.run(Thread.java:844)
Caused by: java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at javafx.base/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1784)
... 47 more
Caused by: java.lang.NullPointerException
at sample.Controller.errorPopup(Controller.java:156)
at sample.WebFiles.IndexFile.seasonIndex(IndexFile.java:225)
at sample.Controller.search(Controller.java:174)
... 58 more