本文介紹了無法從 JavaFX 中的 MenuItem 獲取場景的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我正在嘗試根據(jù) menuItem 單擊更改 javafx 階段中的場景.這是我的 sample.fxml:
I am trying to change the scene in a javafx stage based on menuItem click. Here is my 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>
這是我的 Controller.java:
Here is my 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.
}
}
這是我的 Main.java:
Here is my 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);
}
}
當我點擊 Accounts Menu 下的 menuItem Manage 時，出現(xiàn)以下異常:
When I click on the menuItem Manage under Accounts Menu, I get the following exception:
"C:Program FilesJavajdk1.7.0_17injava" -Didea.launcher.port=7541 "-Didea.launcher.bin.path=C:Program Files (x86)JetBrainsIntelliJ IDEA 12.1.4in" -Dfile.encoding=UTF-8 -classpath "C:Program FilesJavajdk1.7.0_17jrelibcharsets.jar;C:Program FilesJavajdk1.7.0_17jrelibdeploy.jar;C:Program FilesJavajdk1.7.0_17jrelibjavaws.jar;C:Program FilesJavajdk1.7.0_17jrelibjce.jar;C:Program FilesJavajdk1.7.0_17jrelibjfr.jar;C:Program FilesJavajdk1.7.0_17jrelibjfxrt.jar;C:Program FilesJavajdk1.7.0_17jrelibjsse.jar;C:Program FilesJavajdk1.7.0_17jrelibmanagement-agent.jar;C:Program FilesJavajdk1.7.0_17jrelibplugin.jar;C:Program FilesJavajdk1.7.0_17jrelib
esources.jar;C:Program FilesJavajdk1.7.0_17jrelib
t.jar;C:Program FilesJavajdk1.7.0_17jrelibextaccess-bridge-64.jar;C:Program FilesJavajdk1.7.0_17jrelibextdnsns.jar;C:Program FilesJavajdk1.7.0_17jrelibextjaccess.jar;C:Program FilesJavajdk1.7.0_17jrelibextlocaledata.jar;C:Program FilesJavajdk1.7.0_17jrelibextsunec.jar;C:Program FilesJavajdk1.7.0_17jrelibextsunjce_provider.jar;C:Program FilesJavajdk1.7.0_17jrelibextsunmscapi.jar;C:Program FilesJavajdk1.7.0_17jrelibextzipfs.jar;C:Users
ahulserverIdeaProjectsDrawingTextoutproductionDrawingText;C:Program Files (x86)JetBrainsIntelliJ IDEA 12.1.4libidea_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$6.handle(ContextMenuContent.java:1139)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$6.handle(ContextMenuContent.java:1137)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3328)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3168)
at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3123)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1563)
at javafx.scene.Scene$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.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:55)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:269)
at javafx.fxml.FXMLLoader$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
那么如何從菜單項單擊事件處理程序中獲取包含階段/場景?
So how do I get the containing stage/scene from the menu Item clicked event handler?
編輯線
Node node= (Node)event.getSource();
在 controller.java 中是第 29 行，這會產(chǎn)生問題.
in controller.java is line number 29 which is giving problems.
推薦答案
你真正的錯誤顯示在堆棧跟蹤的倒數(shù)第二行:
Your real error is shown in the second to last line of the stack trace:
Caused by: java.lang.ClassCastException: javafx.scene.control.MenuItem cannot be cast to javafx.scene.Node
at sample.Controller.onTweetsMenuActionPerformed(Controller.java:29)
此錯誤指的是控制器中的以下行:
This error is referring to the following line from your controller:
Node node= (Node)event.getSource();
查看 JavaFX API 文檔，MenuItem 和 Menu 都不是 Node 的子類.http://docs.oracle.com/javafx/2/api/javafx/場景/控制/MenuItem.htmlhttp://docs.oracle.com/javafx/2/api/javafx/場景/控制/Menu.html
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.html http://docs.oracle.com/javafx/2/api/javafx/scene/control/Menu.html
我建議將源作為對象獲取，然后在繼續(xù)之前檢查其類型.另外，我在使用 getSource() 方法時遇到了問題；getTarget() 方法對我來說效果更好.不管怎樣，你仍然需要一種方法來進入舞臺.
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.
為此，您可能希望在 FXML 中使用 fx:id 標簽，而不是 id 標簽.這將允許您將 FXML 元素直接注入到您的控制器中.例如，您可以通過將 MenuBar 元素注入控制器來從 MenuBar(它是 Node 的子類)中獲取舞臺.
To do this, you might want to use the fx:id tag in your FXML instead of the id tag. 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.
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">
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();
}
...
}
您可能需要在此處進行一些調(diào)整，但希望對您有所幫助.
You may need to do a bit of tweaking here, but hopefully it helps.
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