76 岁的我正在努力学习 Java，并制作了一些成功改变场景的会计相关教程。现在查看使用菜单栏和菜单项的结构，以处理将 14 个章节链接为菜单栏上的项目之一。
我见过/看过的所有示例都为每个 MenuItem 显示了一个简单的 println。我的这个工作正常，但是当我尝试从我以前的应用程序复制我的 FXMLLoader 时，它不喜欢它。
我得到这个找不到符号:符号:方法 getScene() 位置:MenuItem 类型的变量 mbarchapter1
我的代码是:
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
}
}
我的 FXML 文件有针对菜单项的 fx:ids。如下图所示:
<?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>
这是运行应用程序时的输出:
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
更正了第二个 .fxml 文件，将 MenuButton 更改为 MenuItem。这是输出部分的结果:
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)
感谢任何帮助
最佳答案
MenuItem不是 Node 的子类，因此它不会继承 getScene() method .
最简单的解决方案就是在您知道与包含菜单项的菜单栏位于同一场景中的任何场景图节点上调用 getScene()。
stage = (Stage) someNode.getScene().getWindow();
其中 someNode 是您使用 @FXML 注入(inject)到 Controller 中的任何 Node。
由于您目前只有 MenuItem 注入(inject)到您的 Controller 中，因此您需要为此目的注入(inject)一些节点。最自然的是 FXML 的根。为此，将 fx:id="root" 属性添加到 FXML 的根元素，然后只需更改 Controller 中 root 字段的声明，以便它被注入(inject):
@FXML
private Parent root ;
然后
stage = (Stage) root.getScene().getWindow();
应该根据需要为您提供当前的 Stage。
关于JavaFX:如何从 MenuItem 更改场景(FXML)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29605277/