JavaFX：如何从 MenuItem 更改场景 (FXML)

Question

At 76, I am trying to learn Java and have produced a number of accounting related tutorials that successfully change scenes. Now looking at a structure using menubar and menu items to cope with linking 14 chapters as one of the items on the menubar.

All examples I have seen/watched show a simple println for each MenuItem . I have this working OK, but when I try to copy my FXMLLoader from my previous applications it doesn't like it.

I get this cannot find symbol: symbol: method getScene() location: variable mbarchapter1 of type MenuItem

My code is:

package accountingsnapshots;

import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.MenuItem;


import javafx.stage.Stage;

public class AccountingSnapshotsController implements Initializable {

    @FXML
    private MenuItem mbarhome;
    @FXML
    private MenuItem mbarchapter1;
    @FXML
    private MenuItem mbarchapter2;
    @FXML
    private MenuItem mbarchapter3;
    @FXML
    private MenuItem mbarchapter4;
    @FXML
    private MenuItem mbarcalculator;
    @FXML
    private MenuItem mbarglossary;
    @FXML
    private MenuItem mbarhelp;


    Stage stage; 
    @FXML Parent root;

    @FXML
    private void handleButtonAction(ActionEvent e) throws IOException {

    if(e.getSource()==mbarhome){
           System.out.println("this is Home");
        }

    else if(e.getSource()==mbarchapter1){
            System.out.println("this is chap 1");  

            //get reference to the button's stage
            stage = (Stage) root.getScene().getWindow();
            //load up OTHER FXML document
            root = FXMLLoader.load(getClass().getResource("AccountingSnapshots_1.fxml"));

        //create a new scene with root and set the stage
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
        }

    else if(e.getSource()==mbarchapter2){
            System.out.println("this is chap 2");       
        }

    else if(e.getSource()==mbarchapter3){
            System.out.println("this is chap 3");       
        }

    else if(e.getSource()==mbarchapter4){
            System.out.println("this is chap 4");       
        }

    else if(e.getSource()==mbarcalculator){
            System.out.println("this is Calculator");       
        }

    else if(e.getSource()==mbarglossary){
            System.out.println("this is Glossary");       
        }

    else if(e.getSource()==mbarhelp){
            System.out.println("this is Help"); 

        }

    }


    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

}

My FXML file has fx:ids against the menuItems. Shown below:

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

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

<AnchorPane id="AnchorPane" prefHeight="600.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="accountingsnapshots.AccountingSnapshotsController">
   <children>
      <MenuBar layoutY="-1.0" prefHeight="30.0" prefWidth="858.0">
        <menus>
          <Menu fx:id="mbarhome" mnemonicParsing="false" onAction="#handleButtonAction" text="Home">
            <items>
              <MenuItem mnemonicParsing="false" text="Home" />
            </items>
          </Menu>
          <Menu mnemonicParsing="false" text="Chapters">           
            <items>
              <MenuItem fx:id="mbarchapter1" mnemonicParsing="false" onAction="#handleButtonAction" text="Ch.1 - Introduction to final accounts" />
              <MenuItem fx:id="mbarchapter2" mnemonicParsing="false" onAction="#handleButtonAction" text="Ch.2 - Double entry bookkeeping" />
              <MenuItem fx:id="mbarchapter3" mnemonicParsing="false" onAction="#handleButtonAction" text="Ch.3 - Accounting adjustments" />
              <MenuItem fx:id="mbarchapter4" mnemonicParsing="false" onAction="#handleButtonAction" text="Ch.4 - Introduction to final accounts" />
            </items>
          </Menu>
          <Menu fx:id="mbarcalculator" mnemonicParsing="false" onAction="#handleButtonAction" text="Calculator">
            <items>
              <MenuItem mnemonicParsing="false" text="Calculator" />
            </items>           
          </Menu>
          <Menu fx:id="mbarglossary" mnemonicParsing="false" onAction="#handleButtonAction" text="Glossary">
            <items>
              <MenuItem mnemonicParsing="false" text="Glossary" />
            </items>
          </Menu>
          <Menu fx:id="mbarhelp" mnemonicParsing="false" onAction="#handleButtonAction" text="Help">
            <items>
              <MenuItem mnemonicParsing="false" text="Help" />
            </items>
          </Menu>
        </menus>
      </MenuBar>
   </children>
</AnchorPane>

This is the output when running the application:

Created dir: C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\build\empty
Created dir: C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\build\generated-sources\ap-source-output
Compiling 2 source files to C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\build\classes
Copying 5 files to C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\build\classes
compile:
Created dir: C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\dist
Detected JavaFX Ant API version 1.3
Launching <fx:jar> task from C:\Program Files\Java\jdk1.8.0_31\jre\..\lib\ant-javafx.jar
Warning: From JDK7u25 the Codebase manifest attribute should be used to restrict JAR repurposing.
         Please set manifest.custom.codebase property to override the current default non-secure value '*'.
Launching <fx:deploy> task from C:\Program Files\Java\jdk1.8.0_31\jre\..\lib\ant-javafx.jar
jfx-deployment-script:
jfx-deployment:
jar:
Copying 12 files to C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\dist\run53408212
jfx-project-run:
Executing C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\dist\run53408212\AccountingSnapshots.jar using platform C:\Program Files\Java\jdk1.8.0_31\jre/bin/java
this is chap 1
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1762)
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1645)
    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$MenuItemContainer.doSelect(ContextMenuContent.java:1364)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren$324(ContextMenuContent.java:1317)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$$Lambda$147/1926554713.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:3724)
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:553)
    at com.sun.glass.ui.View.notifyMouse(View.java:925)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102)
    at com.sun.glass.ui.win.WinApplication$$Lambda$37/96639997.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1757)
    ... 43 more
Caused by: javafx.fxml.LoadException: 
file:/C:/Users/john/Documents/NetBeansProjects/AccountingSnapshots/dist/run53408212/AccountingSnapshots.jar!/accountingsnapshots/AccountingSnapshots_1.fxml:16

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2595)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2435)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3208)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3169)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3142)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3118)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3098)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3091)
    at accountingsnapshots.AccountingSnapshotsController.handleButtonAction(AccountingSnapshotsController.java:53)
    ... 53 more
Caused by: java.lang.IllegalArgumentException: Unable to coerce MenuButton@35398aab[styleClass=menu-button]'Home' to class javafx.scene.control.MenuItem.
    at com.sun.javafx.fxml.BeanAdapter.coerce(BeanAdapter.java:495)
    at javafx.fxml.FXMLLoader$PropertyElement.add(FXMLLoader.java:1387)
    at javafx.fxml.FXMLLoader$ValueElement.processEndElement(FXMLLoader.java:784)
    at javafx.fxml.FXMLLoader.processEndElement(FXMLLoader.java:2817)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2526)
    ... 61 more

Corrected the second .fxml file, changing MenuButton to MenuItem. This is the result in the output section:

ant -f C:\\Users\\john\\Documents\\NetBeansProjects\\AccountingSnapshots jfxsa-run
init:
Deleting: C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\build\built-jar.properties
deps-jar:
Updating property file: C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\build\built-jar.properties
compile:
Detected JavaFX Ant API version 1.3
jfx-deployment:
jar:
Copying 12 files to C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\dist\run581163156
jfx-project-run:
Executing C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\dist\run581163156\AccountingSnapshots.jar using platform C:\Program Files\Java\jdk1.8.0_31\jre/bin/java
this is chap 1
Deleting directory C:\Users\john\Documents\NetBeansProjects\AccountingSnapshots\dist\run581163156
jfxsa-run:
BUILD SUCCESSFUL (total time: 19 seconds)

Any help appreciated

Answer 1

MenuItem is not a subclass of Node , so it doesn't inherit a getScene() method .

The simplest solution is just to call getScene() on any scene graph node which you know to be in the same scene as the menubar containing your menu item.

stage = (Stage) someNode.getScene().getWindow();

where someNode is any Node that you have injected into your controller with @FXML .

As you currently only have MenuItem s injected into your controller, you need to inject some node for this purpose. The most natural one would be the root of the FXML. To do this, add a fx:id="root" attribute to your FXML's root element, and then just change the declaration of the root field in the controller so that it is injected:

@FXML
private Parent root ;

Then

stage = (Stage) root.getScene().getWindow();

should give you the current Stage , as needed.

Answer 2

This is an old thread, but the answer given was spot on

Here's a bit of code for anyone that's facing the same issues

Normally, I would just pass in a node to the stage object, but as has already been stated - a menu/menuItem cannot be converted to a node. Using the fx:id of the outermost node solves the problem. reportAnchorpane is the name of the (root) node for this respective FXML

public void gotoReports(ActionEvent e) throws IOException {
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("/Reports/Reports.fxml"));
Parent ReportManager = loader.load();
Scene ReportManagerScene = new Scene(ReportManager);

Stage window = (Stage)reportAnchorPane.getScene().getWindow();

window.setScene(ReportManagerScene);

window.show();
}

On the FXML

<AnchorPane fx:id="reportAnchorPane" prefHeight="500.0" prefWidth="800.0" styleClass="mainFxmlClass" fx:controller="Reports.ReportsController">
    <stylesheets>
        <URL value="@reports.css" />
    </stylesheets>
      
    <children>
        <HBox fx:id="Menu" prefHeight="25.0" prefWidth="925.0">
            <children>
                <MenuBar fx:id="MenuBar" prefHeight="25.0" prefWidth="925.0">
                    <menus>
                        <Menu mnemonicParsing="false" text="Window" >
                            <items>                           
                                <MenuItem fx:id="miGotoReportsPage" mnemonicParsing="false" text="Reports" onAction="#gotoReports"/>   
                            </items>
                        </Menu>                       
                    </menus>
                </MenuBar>
            </children>
        </HBox>
    </children>
</AnchorPane>