在边框中心加载新的 fxml [英] Load new fxml in borderpane center
本文介绍了在边框中心加载新的 fxml的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
刚开始使用 JavaFx(通常也是 Java 的初学者)，几天来我一直试图让它工作，但我一直无法解决它.我收到了一个空指针异常，我知道这里涵盖了它:什么是 NullPointerException，我该如何解决?
Just started with JavaFx (also a beginner of java generally) and for a few days I've been trying to get this to work but I've been unable to solve it. I'm getting a null pointer exception which I know is covered here: What is a NullPointerException, and how do I fix it?
所以我希望这个问题不会因为重复而被关闭，因为我知道 npe 是什么并且(通常)知道如何解决这个问题.
So I hope this question doesn't get closed as duplicate since I know what npe is and (generally) know how to fix this.
我也知道(大部分时间)如何躲避它们和/或在它们发生时修复它们，但在这种情况下我只是不知道如何解决它.
I also know (most of the time) how to dodge them and/or fix them if it occurs but in this case I just don't know how to sort it out.
我还检查了一些有关 fxml 的其他问题，但仍然无法弄清楚.
如何在 javaFx borderPane 中从 LeftPane 更改 CenterPane?
在 javaFX 中的 BorderPane 中的窗格之间切换
在同一场景中加载新的 fxml
I've also checked some other questions regarding fxml but still can't figure is out.
How to change CenterPane from LeftPane in javaFx borderPane?
switching between panes in BorderPane in javaFX
Loading new fxml in the same scene
在我的应用程序中，我想要一个边框作为根，在左侧我有三个按钮，根据我按下的按钮，一个带有 tabpane 的新 fxml 应该加载到边框的中心，当我按下时我得到一个 npe 的按钮，我认为是因为我没有引用正确的边框，但我看不出哪里出错了.
In my application I want to have a borderpane as a root and in the left side i have three buttons and depending on what button I press a new fxml with a tabpane should load in the center of the borderpane how ever when i press the button i get a npe which i presume is due to me not referencing the right borderpane but i cant see where i'm going wrong.
我想要做的是当我按下按钮 custMenuButton 时，fxml 应该加载并设置为边框的中心.
What I'm trying to do is when i press the button custMenuButton the fxml should load and be set as center in the borderpane.
主类
import java.io.IOException;
import javafx.application.Application;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class Main extends Application {
@FXML
private BorderPane root;
Stage window;
@Override
public void start(Stage primaryStage) throws IOException {
window = primaryStage;
FXMLLoader loader = new FXMLLoader(Main.class.getResource("MainWindowView.fxml"));
this.root = loader.load();
MainWindowController mwc = new MainWindowController();
mwc.setMain(this);
Scene scene = new Scene(root);
window.setTitle("JavaFX");
window.setScene(scene);
window.show();
}
public static void main(String[] args) {
launch(args);
}
public BorderPane getBorderPane() {
return root;
}
}
主窗口控制器
import java.io.IOException;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.Button;
import javafx.scene.control.TabPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;
public class MainWindowController {
private Main main;
@FXML private BorderPane root;
@FXML private VBox sideBox;
@FXML private Button custMenuButton;
@FXML private Button accMenuButton;
@FXML private Button transMenuButton;
public void setMain(Main main) {
this.main = main;
}
public void handleCustMenuButton() throws IOException {
FXMLLoader loader = new FXMLLoader(getClass().getResource("CustomerView.fxml"));
TabPane pane = (TabPane) loader.load();
CustomerViewController cvc = loader.getController();
cvc.setMain(main);
main.getBorderPane().setCenter(pane);
}
}
客户视图控制器
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
public class CustomerViewController implements Initializable {
Main main;
@FXML private TabPane custTabPane;
@FXML private Tab createTab;
@FXML private Tab listAllTab;
@FXML private Tab deleteTab;
public void setMain(Main main){
this.main = main;
}
@Override
public void initialize(URL url, ResourceBundle rb) {
// TODO
}
}
主窗口视图
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Menu?>
<?import javafx.scene.control.MenuBar?>
<?import javafx.scene.control.MenuItem?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.VBox?>
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="600.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/8.0.141" xmlns:fx="http://javafx.com/fxml/1" fx:controller="firstfx.MainWindowController">
<top>
<MenuBar BorderPane.alignment="CENTER">
<menus>
<Menu mnemonicParsing="false" text="File">
<items>
<MenuItem mnemonicParsing="false" text="Close" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Help">
<items>
<MenuItem mnemonicParsing="false" text="About" />
</items>
</Menu>
</menus>
</MenuBar>
</top>
<left>
<VBox fx:id="sideBox" prefHeight="200.0" prefWidth="150.0" spacing="2.0" BorderPane.alignment="CENTER">
<children>
<Button fx:id="custMenuButton" mnemonicParsing="false" onAction="#handleCustMenuButton" prefHeight="50.0" prefWidth="130.0" text="Kundmeny" />
<Button fx:id="accMenuButton" mnemonicParsing="false" prefHeight="50.0" prefWidth="130.0" text="Kontomeny" />
<Button fx:id="transMenuButton" mnemonicParsing="false" prefHeight="50.0" prefWidth="130.0" text="Transaktioner" />
</children>
<padding>
<Insets bottom="10.0" left="10.0" right="10.0" top="10.0" />
</padding>
</VBox>
</left>
</BorderPane>
客户视图 fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Tab?>
<?import javafx.scene.control.TabPane?>
<?import javafx.scene.layout.AnchorPane?>
<TabPane fx:id="custTabPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" tabClosingPolicy="UNAVAILABLE" xmlns="http://javafx.com/javafx/8.0.141" xmlns:fx="http://javafx.com/fxml/1" fx:controller="firstfx.CustomerViewController">
<tabs>
<Tab fx:id="createTab" text="Skapa kund">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="180.0" prefWidth="200.0" />
</content>
</Tab>
<Tab fx:id="listAllTab" text="Lista alla kunder">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="180.0" prefWidth="200.0" />
</content>
</Tab>
<Tab fx:id="deleteTab" text="Radera kund">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="180.0" prefWidth="200.0" />
</content>
</Tab>
</tabs>
</TabPane>
堆栈跟踪
Executing /home/garnbutik/NetBeansProjects/FirstFX/dist/run1223809748/FirstFX.jar using platform /home/garnbutik/jdk1.8.0_151/jre/bin/java
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
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.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.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.Node.fireEvent(Node.java:8413)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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.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$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$353(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$48(GtkApplication.java:139)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 48 more
Caused by: java.lang.NullPointerException
at firstfx.MainWindowController.handleCustMenuButton(MainWindowController.java:31)
... 58 more
BUILD STOPPED (total time: 4 minutes 14 seconds)
推荐答案
您不要在加载 MainWindowView.fxml 时创建的控制器上调用 setMain(...).因此在 MainWindowController 中，当您尝试执行
You don't call setMain(...) on the controller that is created when you load MainWindowView.fxml. Consequently in MainWindowController when you try to do
main.getBorderPane()...
你得到一个空指针异常.
you get a null pointer exception.
在您的 start() 方法中，您需要以与稍后在 handleCustMenuButton(...) 中相同的方式获取控制器，即
In your start() method, you need to get the controller in the same way you do later in handleCustMenuButton(...), i.e.
FXMLLoader loader = new FXMLLoader(Main.class.getResource("MainWindowView.fxml"));
this.root = loader.load();
// MainWindowController mwc = new MainWindowController();
MainWindowController mwc = loader.getController();
mwc.setMain(this);
这篇关于在边框中心加载新的 fxml的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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