JavaFX 8:javafx.fxml.LoadException - fxmlLoader.load() 不起作用,但 fxmlLoader.getController() 起作用

JavaFX 8: javafx.fxml.LoadException - fxmlLoader.load() doesn't work, but fxmlLoader.getController() does

尝试从 FXML 文件加载控制器时出现 LoadException。这是 FXML 文件:

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>


<VBox maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Interface.ChangeProjoOrderController">
   <children>
      <HBox prefHeight="100.0" prefWidth="200.0">
         <children>
            <ScrollPane prefHeight="200.0" prefWidth="200.0">
              <content>
                <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="200.0" prefWidth="200.0">
                     <children>
                        <GridPane>
                          <columnConstraints>
                            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                          </columnConstraints>
                          <rowConstraints>
                            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                          </rowConstraints>
                        </GridPane>
                     </children>
                  </AnchorPane>
              </content>
            </ScrollPane>
            <VBox prefHeight="200.0" prefWidth="100.0">
               <children>
                  <Button mnemonicParsing="false" text="Button" />
                  <Button mnemonicParsing="false" text="Button" />
               </children>
            </VBox>
         </children>
      </HBox>
      <ToolBar prefHeight="40.0" prefWidth="200.0">
        <items>
            <Button mnemonicParsing="false" text="Button" />
          <Button mnemonicParsing="false" text="Button" />
            <Button mnemonicParsing="false" text="Button" />
            <Button mnemonicParsing="false" text="Button" />
        </items>
      </ToolBar>
      <HBox prefHeight="100.0" prefWidth="200.0">
         <children>
            <Button mnemonicParsing="false" text="Button" />
            <Button mnemonicParsing="false" text="Button" />
         </children>
      </HBox>
   </children>
</VBox>

加载FXML的Window是:

package Interface;

import java.io.IOException;
import java.util.ArrayList;
import java.util.logging.Logger;

import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import Engine.PackageLight.Projector;

public class ChangeProjoOrderWindow
{
 private MainWindowController mainController;
 
 private FXMLLoader fxmlLoader = null;
 private VBox root = null;//TODO uncomment me
 //private Parent root = null;//TODO delete me
 private ChangeProjoOrderController controller;
 private Scene scene;
 private Stage stage;
 
 private static final Logger logUI = Logger.getLogger("UI");
 
 
 ChangeProjoOrderWindow(MainWindowController c)
 {
  mainController = c;
  
  try
  {
   fxmlLoader = new FXMLLoader(getClass().getResource("fxml/projectorOrder.fxml"));
   root = (VBox)fxmlLoader.load();//TODO uncomment me
   //root = (Parent)fxmlLoader.load();//TODO delete me
   
   //XXX DO NOT do this !! The controller will stay null (uninitialized)
   //root = FXMLLoader.load(getClass().getResource("fxml/orderProjo.fxml"));
  }
  catch(IOException e)
  {
   logUI.severe("Error: Cannot load the FXML file 'projectorOrder.fxml'.");
   e.printStackTrace();
  }
  
  controller = fxmlLoader.<ChangeProjoOrderController>getController();
  if(controller == null)
   System.err.println("controller is null");
  scene = new Scene(root);
  
  System.exit(0);
  
  stage = new Stage();
  stage.setOnCloseRequest(we -> 
  {
   // Application termination event
   c.setChangeProjectorOrderDisableStatus(false);
   stage.close();
   logUI.fine("orderProjo terminated.");
  });
  
  mainController.windows.executePreChangeProjectorOrder();
  
  stage.setTitle("Modifier l'ordre des projecteurs");
  stage.setScene(scene);
  stage.show();
  
  controller.setMainController(mainController);
  controller.setStage(stage);
 }
 
 protected void setProjectors(ArrayList<Projector> projectors){controller.setProjectors(projectors);}
}

这是控制器:

package Interface;

import java.net.URL;
import java.util.ArrayList;
import java.util.ResourceBundle;
import java.util.logging.Logger;

import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;
import Engine.PackageLight.Projector;

public class ChangeProjoOrderController implements Initializable
{
 /*@FXML private Button up;
 @FXML private Button down;
 @FXML private Button newProjo;
 @FXML private Button remove;
 @FXML private Button duplicate;
 @FXML private Button edit;
 @FXML private Button ok;
 @FXML private Button cancel;
 
 @FXML private GridPane gridPane;*/
 
 private MainWindowController mainController;
 private Stage stage;
 
 private ArrayList<Projector> projectorList = null;
 
 private static final Logger logUI = Logger.getLogger("UI");
 
 @Override
 public void initialize(URL location, ResourceBundle resources)
 {
  /*cancel.setOnAction(event ->
  {
   logUI.info("cancel");
   mainController.setChangeProjectorOrderDisableStatus(false);
   stage.close();
  });
  
  ok.setOnAction(event ->
  {
   logUI.info("ok");
   mainController.setChangeProjectorOrderDisableStatus(false);
   stage.close();
  });*/
  
  initProjectors();
 }
 
 private void initProjectors()
 {
  for(int i=0; i<projectorList.size(); i++)
  {
   Label curr = new Label(Integer.toString(i));
   GridPane.setColumnIndex(curr, 0);
   GridPane.setRowIndex(curr, i);
  }
 }
 
 protected void setMainController(MainWindowController c){mainController = c;}
 protected void setStage(Stage s){stage = s;}
 protected void setProjectors(ArrayList<Projector> projectors){projectorList = projectors;}
}

最后,堆栈跟踪:

INFO [UI] Interface.Windows - changeProjoOrder
  Changing the order of the projectors...
[0m[31m[1mSEVERE [UI] Interface.ChangeProjoOrderWindow - <init>
  Error: Cannot load the FXML file 'projectorOrder.fxml'.
[0mjavafx.fxml.LoadException: 
/home/filou/workspace/java/syncart/bin/Interface/fxml/projectorOrder.fxml

 at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2605)
 at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2583)
 at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2445)
 at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2413)
 at Interface.ChangeProjoOrderWindow.<init>(ChangeProjoOrderWindow.java:35)
 at Interface.Windows.changeProjoOrder(Windows.java:151)
 at Interface.MainWindowController.changeProjoOrder(MainWindowController.java:308)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:497)
 at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
 at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:497)
 at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
 at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1767)
 at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1653)
 at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
 at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
 at javafx.event.Event.fireEvent(Event.java:198)
 at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
 at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1405)
 at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren1(ContextMenuContent.java:1358)
 at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$$Lambda8/1949840625.handle(Unknown Source)
 at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
 at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
 at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
 at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
 at javafx.event.Event.fireEvent(Event.java:198)
 at javafx.scene.Scene$MouseHandler.process(Scene.java:3758)
 at javafx.scene.Scene$MouseHandler.access00(Scene.java:3486)
 at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
 at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2495)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:350)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275)
 at java.security.AccessController.doPrivileged(Native Method)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent0(GlassViewEventHandler.java:385)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda7/365619965.get(Unknown Source)
 at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:404)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:384)
 at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
 at com.sun.glass.ui.View.notifyMouse(View.java:927)
 at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
 at com.sun.glass.ui.gtk.GtkApplication.lambda$null(GtkApplication.java:139)
 at com.sun.glass.ui.gtk.GtkApplication$$Lambda/1327763628.run(Unknown Source)
 at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
 at Interface.ChangeProjoOrderController.initProjectors(ChangeProjoOrderController.java:58)
 at Interface.ChangeProjoOrderController.initialize(ChangeProjoOrderController.java:53)
 at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2552)
 ... 61 more
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
 at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1770)
 at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1653)
 at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
 at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
 at javafx.event.Event.fireEvent(Event.java:198)
 at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
 at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1405)
 at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren1(ContextMenuContent.java:1358)
 at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$$Lambda8/1949840625.handle(Unknown Source)
 at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
 at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
 at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
 at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
 at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
 at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
 at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
 at javafx.event.Event.fireEvent(Event.java:198)
 at javafx.scene.Scene$MouseHandler.process(Scene.java:3758)
 at javafx.scene.Scene$MouseHandler.access00(Scene.java:3486)
 at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
 at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2495)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:350)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275)
 at java.security.AccessController.doPrivileged(Native Method)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent0(GlassViewEventHandler.java:385)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda7/365619965.get(Unknown Source)
 at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:404)
 at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:384)
 at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
 at com.sun.glass.ui.View.notifyMouse(View.java:927)
 at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
 at com.sun.glass.ui.gtk.GtkApplication.lambda$null(GtkApplication.java:139)
 at com.sun.glass.ui.gtk.GtkApplication$$Lambda/1327763628.run(Unknown Source)
 at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:497)
 at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
 at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:497)
 at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
 at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1767)
 ... 46 more
Caused by: java.lang.NullPointerException: Root cannot be null
 at javafx.scene.Scene.<init>(Scene.java:336)
 at javafx.scene.Scene.<init>(Scene.java:194)
 at Interface.ChangeProjoOrderWindow.<init>(ChangeProjoOrderWindow.java:50)
 at Interface.Windows.changeProjoOrder(Windows.java:151)
 at Interface.MainWindowController.changeProjoOrder(MainWindowController.java:308)
 ... 56 more

好的。现在问题似乎来自行

root = (VBox)fxmlLoader.load();//TODO uncomment me

这会导致 IOException。但是之后,行

controller = fxmlLoader.<ChangeProjoOrderController>getController();
  if(controller == null)
   System.err.println("controller is null");

不打印 "controller is null"。所以控制器已正确加载,但 "root" 不是。我已经检查了“@FXML”标签(我最后注释掉了......无济于事),FXML 文件中的 "fx:controller"(它的写法与另一个有效的文件相同,即 Interface.xxx),我从头开始用 SceneBuilder 2.0 重新制作了 window 以确保 FXML 生成良好,我尝试将 "root" 设置为 "Parent" 或 "VBox" 并且我将我的文件与其他有效的文件进行了比较。

构建的window没有出现

我正在使用: Lubuntu 3.13.0-46-通用, JavaFX 8 u40, Eclipse Mars Milestone 3 (4.5.0M3) Build id 20141113-0320, JavaFx SceneBuilder 2.0-b20

那么为什么我有这个异常?它来自哪里?

我不确定这是否清楚,我已经使用这段代码很长时间了:P 如果需要更多信息,请告诉我;我来提供。

谢谢

堆栈跟踪表明异常来自 ChangeProjoOrderController 的第 58 行。

我猜这是

for(int i=0; i<projectorList.size(); i++)

这是有道理的,因为你初始化了

private ArrayList<Projector> projectorList = null;

并且不要更改它的值,至少在加载 FXML 之后(并调用 initalize() 方法)。