无法从 JavaFX 中的 MenuItem 获取场景
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Unable to get Scene from MenuItem in JavaFX
提问by rahulserver
I am trying to change the scene in a javafx stage based on menuItem click. Here is my sample.fxml:
我正在尝试根据 menuItem 单击更改 javafx 阶段中的场景。这是我的 sample.fxml：
<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import java.net.*?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.*?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.image.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.GridPane?>
<AnchorPane prefHeight="-1.0" prefWidth="560.0" styleClass="background" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="sample.Controller">
<children>
<MenuBar layoutY="0.0" maxWidth="1.7976931348623157E308" prefWidth="300.0" useSystemMenuBar="false" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="2.0">
<menus>
<Menu id="manageAccountsMenu" mnemonicParsing="false" onAction="#onManageAccountsMenuActionPerformed" text="Accounts" fx:id="manageAccountsMenu">
<items>
<MenuItem mnemonicParsing="false" onAction="#onTweetsMenuActionPerformed" text="Manage" fx:id="manageAccountsSubmenuItem" />
</items>
</Menu>
<Menu mnemonicParsing="false" onAction="#onTweetsMenuActionPerformed" text="Tweets" fx:id="tweetsMenuItem" />
<Menu mnemonicParsing="false" text="Retweets" />
</menus>
</MenuBar>
<VBox id="VBox" alignment="CENTER" layoutY="24.0" spacing="5.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0">
<children>
<ScrollPane id="ScrollPane" fitToHeight="true" fitToWidth="true" prefViewportHeight="400.0" prefViewportWidth="300.0">
<content>
<TableView prefHeight="-1.0" prefWidth="-1.0" tableMenuButtonVisible="true">
<columns>
<TableColumn editable="false" prefWidth="75.0" text="SNO" />
<TableColumn prefWidth="200.0" text="Account" />
<TableColumn prefWidth="200.0" text="Status" />
<TableColumn prefWidth="75.0" text="Actions" />
</columns>
</TableView>
</content>
</ScrollPane>
<Button mnemonicParsing="false" text="Add Account" textAlignment="CENTER">
<graphic>
<ImageView fitHeight="150.0" fitWidth="200.0" mouseTransparent="true" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@addAccount.png" />
</image>
</ImageView>
</graphic>
</Button>
</children>
</VBox>
</children>
<stylesheets>
<URL value="@darkTheme.css" />
</stylesheets>
</AnchorPane>
Here is my Controller.java:
这是我的 Controller.java：
package sample;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.MenuItem;
import javafx.stage.Stage;
import java.net.URL;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
protected void onManageAccountsMenuActionPerformed(ActionEvent event) {
System.out.println("Manage Accbtnclick");
// Node node=(Node) event.getSource();
// Stage stage=(Stage) node.getScene().getWindow();
//
// Scene scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
}
@FXML
protected void onTweetsMenuActionPerformed(ActionEvent event) {
System.out.println("Manage Accbtnclick");
Node node= (Node)event.getSource();
Stage stage=(Stage) node.getScene().getWindow();
Scene scene = Main.screens.get("tweet");
stage.setScene(scene);
stage.show();
}
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
//To change body of implemented methods use File | Settings | File Templates.
}
}
Here is my Main.java:
这是我的 Main.java：
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.geometry.Pos;
import javafx.scene.Group;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressBar;
import javafx.scene.control.ProgressIndicator;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.io.IOException;
import java.util.HashMap;
public class Main extends Application {
public static HashMap<String,Scene> screens=new HashMap<String,Scene>();
@Override
public void start(Stage stage) {
try {
Parent accountScreen= FXMLLoader.load(getClass().getResource("sample.fxml"));
Parent tweetScreen=FXMLLoader.load(getClass().getResource("tweetform.fxml"));
//Parent retweetScreen=FXMLLoader.load(getClass().getResource("retweetform.fxml"));
screens.put("account",new Scene(accountScreen));
screens.put("tweet",new Scene(tweetScreen));
//screens.put("retweet",new Scene(retweetScreen));
stage.setTitle("Manage Accounts");
stage.setScene(screens.get("account"));
stage.show();
} catch (IOException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
}
public static void main(String[] args) {
launch(args);
}
}
When I click on the menuItem Manage under Accounts Menu, I get the following exception:
当我单击“帐户”菜单下的“管理”菜单项时，出现以下异常：
"C:\Program Files\Java\jdk1.7.0_17\bin\java" -Didea.launcher.port=7541 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA 12.1.4\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.7.0_17\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\jce.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\jfxrt.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\resources.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\rt.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.7.0_17\jre\lib\ext\zipfs.jar;C:\Users\rahulserver\IdeaProjects\DrawingText\out\production\DrawingText;C:\Program Files (x86)\JetBrains\IntelliJ IDEA 12.1.4\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain sample.Main
Manage Accbtnclick
Manage Accbtnclick
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1440)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.control.MenuItem.fire(MenuItem.java:456)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1188)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.handle(ContextMenuContent.java:1139)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.handle(ContextMenuContent.java:1137)
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$MouseHandler.process(Scene.java:3328)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3168)
at javafx.scene.Scene$MouseHandler.access00(Scene.java:3123)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1563)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2265)
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:528)
at com.sun.glass.ui.View.notifyMouse(View.java:922)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access0(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication.run(WinApplication.java:73)
at java.lang.Thread.run(Thread.java:722)
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:601)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:55)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:269)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1435)
... 40 more
Caused by: java.lang.ClassCastException: javafx.scene.control.MenuItem cannot be cast to javafx.scene.Node
at sample.Controller.onTweetsMenuActionPerformed(Controller.java:29)
... 50 more
So how do I get the containing stage/scene from the menu Item clicked event handler?
那么如何从菜单项单击事件处理程序中获取包含的舞台/场景？
EDITThe line
编辑线
Node node= (Node)event.getSource();
in controller.java is line number 29 which is giving problems.
在 controller.java 中是第 29 行，它给出了问题。
回答by Kingand
Your real error is shown in the second to last line of the stack trace:
您真正的错误显示在堆栈跟踪的倒数第二行：
Caused by: java.lang.ClassCastException: javafx.scene.control.MenuItem cannot be cast to javafx.scene.Node
at sample.Controller.onTweetsMenuActionPerformed(Controller.java:29)
This error is referring to the following line from your controller:
此错误指的是控制器中的以下行：
Node node= (Node)event.getSource();
Looking at the JavaFX API Docs, neither MenuItem nor Menu are subclasses of Node. http://docs.oracle.com/javafx/2/api/javafx/scene/control/MenuItem.htmlhttp://docs.oracle.com/javafx/2/api/javafx/scene/control/Menu.html
查看 JavaFX API 文档，MenuItem 和 Menu 都不是 Node.js 的子类。 http://docs.oracle.com/javafx/2/api/javafx/scene/control/MenuItem.html http://docs.oracle.com/javafx/2/api/javafx/scene/control/Menu.html
I would suggest grabbing the source as an Object, then checking its type before continuing. Also, I ran into problems using the getSource() method; the getTarget() method worked better for me. Either way, you still need a way to get the to the Stage.
我建议将源作为对象获取，然后在继续之前检查其类型。另外，我在使用 getSource() 方法时遇到了问题；getTarget() 方法对我来说效果更好。无论哪种方式，您仍然需要一种方法来获得舞台。
To do this, you might want to use the fx:idtag in your FXML instead of the idtag. This will allow you to inject the FXML elements directly into your controller. For example, you could grab the Stage from the MenuBar (which is a subclass of Node) by injecting the MenuBar element into your controller.
为此，您可能希望fx:id在 FXML 中使用标签而不是id标签。这将允许您将 FXML 元素直接注入控制器。例如，您可以通过将 MenuBar 元素注入控制器来从 MenuBar（它是 Node 的子类）中获取舞台。
In the FXML:
在 FXML 中：
<MenuBar fx:id="myMenuBar" layoutY="0.0" maxWidth="1.7976931348623157E308" prefWidth="300.0" useSystemMenuBar="false" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="2.0">
In the controller:
在控制器中：
public class Controller implements Initializable {
@FXML MenuBar myMenuBar;
...
@FXML
protected void onTweetsMenuActionPerformed(ActionEvent event) {
System.out.println("Manage Accbtnclick");
Stage stage = (Stage) myMenuBar.getScene().getWindow();
Scene scene = Main.screens.get("tweet");
stage.setScene(scene);
stage.show();
}
...
}
You may need to do a bit of tweaking here, but hopefully it helps.
您可能需要在这里做一些调整，但希望它有所帮助。
回答by Ryan
Here is a way to get the Sceneand Windowbased on a menu item being clicked without it being an injected FXML element, or without referencing it if you did create it with FXML. In other words by using the Event's target.
这是一种基于单击的菜单项获取Scene和 的Window方法，而该菜单项不是注入的 FXML 元素，或者如果您确实使用 FXML 创建了它，则无需引用它。换句话说，通过使用Event的目标。
In my problem I had a MenuButtonwith a dropdown menu (a ContextMenuas I found out, which I didn't know as I had created my menu in FXML) containing MenuItemsand I wanted to open a FileChooser, which needs the Windowas an argument, when the "Save" MenuItemwas clicked.
在我的问题中，我有一个MenuButton下拉菜单（ContextMenu我发现的一个，我不知道，因为我在 FXML 中创建了我的菜单）包含MenuItems，我想打开一个FileChooser，它需要Window作为参数，当“保存”MenuItem被点击。
Normally I would have gone down the route of getting the event's target, then the Parent, then the next Parent etc. and finally the Scene and then Window. As Menuand MenuItemare not Nodes and therefore do not have Parents In this case however I did the following:
通常我会沿着获取事件目标的路线走下去，然后是父级，然后是下一个父级等等，最后是场景，然后是窗口。As Menuand MenuItemare not Nodes，因此没有Parents 在这种情况下，我做了以下事情：
FileChooser fileChooser = new FileChooser();
MenuItem menuItem = (MenuItem)event.getTarget();
ContextMenu cm = menuItem.getParentPopup();
Scene scene = cm.getScene();
Window window = scene.getWindow();
fileChooser.showSaveDialog(window);
Or, converting the bulk into a one line argument:
或者，将批量转换为一行参数：
FileChooser fileChooser = new FileChooser();
fileChooser.showSaveDialog(((MenuItem)event.getTarget()).getParentPopup().getScene().getWindow());
Just adapt this as necessary based on your own scene-graph (i.e. how many parents you need to get through in cases of sub-menus etc) and what you are wanting to do once you have the Window, but once you get to the ContextMenu(the popup list of MenuItems), you can get the Sceneand then from that get the Window.
只需根据您自己的场景图（即在子菜单等情况下您需要通过多少父母）以及您在拥有后想要做什么Window，但是一旦您到达ContextMenu（ ) 的弹出列表MenuItems，您可以获取Scene，然后从中获取Window.
As an aside, here is the FXML I used to create my MenuButton, and hence why I didn't realise I had to get the ContextMenuthrough a call to getParentPopup()without some trial and error:
顺便说一句，这里是我用来创建我的 FXML MenuButton，因此我没有意识到我必须ContextMenu在getParentPopup()没有反复试验的情况下通过调用：
<MenuButton fx:id="menu" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" prefHeight="34.0" prefWidth="35.0" style="-fx-background-color: #6600ff; -fx-border-width: 0; -fx-mark-color: white; -fx-padding: 5;" textAlignment="CENTER" textFill="WHITE" underline="true">
<items>
<MenuItem fx:id="newSearch" mnemonicParsing="false" text="New Search" onAction="#clearSearch" />
<SeparatorMenuItem />
<MenuItem fx:id="saveSearch" mnemonicParsing="false" text="Save Search" onAction="#saveSearch" />
<MenuItem fx:id="loadSearch" mnemonicParsing="false" text="Load Search" />
<SeparatorMenuItem />
<MenuItem fx:id="saveResults" mnemonicParsing="false" text="Save Results" />
<MenuItem fx:id="loadResults" mnemonicParsing="false" text="Load Results" />
<SeparatorMenuItem />
<MenuItem fx:id="exportResults" mnemonicParsing="false" text="Export Results" />
</items>
<font>
<Font name="Arial" size="12.0" />
</font>
</MenuButton>
回答by sabink6
Stage stage = (Stage) ((Node) myMenuBar).getScene().getWindow();
Stage stage = (Stage) ((Node) myMenuBar).getScene().getWindow();
