[英]Load new fxml in borderpane center
刚开始使用JavaFx(通常也是Java的初学者),几天来,我一直在尝试使其工作,但一直无法解决。 我收到一个空指针异常,该异常在这里介绍: 什么是NullPointerException,如何解决?
所以我希望这个问题不会因为重复而结束,因为我知道npe是什么,并且(通常)知道如何解决此问题。
我也(大多数时候)知道如何躲避它们和/或修复它们(如果发生),但是在这种情况下,我只是不知道如何解决它。
我还检查了有关fxml的其他问题,但仍然无法解决。
如何从javaFx borderPane中的LeftPane更改CenterPane?
在javaFX的BorderPane中的窗格之间切换
在同一场景中加载新的fxml
在我的应用程序中,我想以borderpane为根,在左侧,我有三个按钮,根据我按的是哪个按钮,按新的fxml和一个tabpane应该在borderpane的中心加载,当我按下按钮时,得到一个我认为是由于我没有参考正确的边框的npe,但我看不到我要去哪里错了。
我想做的是当我按下按钮custMenuButton时,fxml应该加载并设置为borderpane的中心。
主班
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;
}
}
主视窗控制器
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)
您不会在加载MainWindowView.fxml
时创建的控制器上调用setMain(...)
。 因此,当您尝试在MainWindowController
中执行此操作时
main.getBorderPane()...
您会得到一个空指针异常。
在start()
方法中,您需要以与稍后在handleCustMenuButton(...)
相同的方式获取控制器,即
FXMLLoader loader = new FXMLLoader(Main.class.getResource("MainWindowView.fxml"));
this.root = loader.load();
// MainWindowController mwc = new MainWindowController();
MainWindowController mwc = loader.getController();
mwc.setMain(this);
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