JavaFX - 将 FXML 组件加载到选项卡时出现 FXML 加载异常

Question

我想要一个带有选项卡的页面，在每个选项卡中我将调用另一个 FXML 组件。 我已经尝试了很多答案，但没有一个对我有用。 我的 TabPane 是home.fxml的主页，并且在我想调用view.fxml的选项卡之一中。 现在，我正在尝试这种方法：

home.fxml 页面：

<VBox xmlns="http://javafx.com/javafx/8"
  xmlns:fx="http://javafx.com/fxml/1"
  prefHeight="${screen.visualBounds.height}"
  fx:controller="pkg.magazineservice.home_controller"
  fx:id="wrapper">

<fx:define>
    <Screen fx:factory="getPrimary" fx:id="screen" />
</fx:define>

<VBox style="-fx-background-color: #003d80" alignment="CENTER" prefHeight="${wrapper.height * 0.10}" >
    <Label BorderPane.alignment="CENTER" style="-fx-text-fill: white" text="Magazine Service" >
        <font>
            <Font size="32" />
        </font>
    </Label>
</VBox>

<TabPane style="-fx-close-tab-animation: none" fx:id="contentWrapper" prefHeight="${wrapper.height * 0.9}" prefWidth="${screen.visualBounds.width}">
    <Tab fx:id="View" text="View">
        <VBox>
            <!--<fx:include source="view.fxml" />-->
        </VBox>
    </Tab>
    <Tab fx:id="Create" text="Create">
        <VBox>
            <!--<fx:include source="view.fxml" />-->
        </VBox>
    </Tab>
    <Tab fx:id="Edit" text="Edit">
        <VBox>
            <!--<fx:include source="view.fxml" />-->
        </VBox>
    </Tab>
</TabPane>

在它的控制器上，我正在尝试初始化一个页面：

home_controller.java

 @Override public void initialize(URL location, ResourceBundle resources) { try { Tab tab = new Tab(); View.setContent((Node) FXMLLoader.load(this.getClass().getResource("view.fxml"))); } catch(IOException iex) { System.out.println(iex.getCause().toString()); System.out.println("File not found"); } }

但是，它不断抛出JavaNullPointerException 。

这是view.fxml ：

 <?xml version="1.0" encoding="UTF-8"?> <?import javafx.scene.control.*?> <?import javafx.scene.layout.*?> <?import javafx.stage.Screen?> <VBox xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:id="View" alignment="CENTER" prefHeight="${screen.height * 0.9}" prefWidth="${screen.visualBounds.width}" fx:controller="pkg.magazineservice.view_controller" > <fx:define> <Screen fx:factory="getPrimary" fx:id="screen" /> </fx:define> <VBox fx:id="listsWrapper" alignment="CENTER" prefHeight="${View.height}" prefWidth="${View.width * 0.50}"> <VBox> </VBox> <Separator orientation="HORIZONTAL" prefWidth="${listsWrapper.width}" style="-fx-background-color: black" /> <VBox> </VBox> <Separator orientation="VERTICAL" prefHeight="${View.height}" style="-fx-background-color: black" /> <VBox fx:id="detailsWrapper" alignment="CENTER" prefHeight="${View.height}" prefWidth="${View.width * 0.50}"> </VBox> </VBox>

我已经尝试过使用fx:root但它一直抱怨没有设置 root 并且我不知道如何从主控制器实现 root。 任何帮助和建议都会很棒！

编辑：堆栈跟踪：

 javafx.fxml.LoadException: /MagazineService/target/classes/pkg/magazineservice/view.fxml:40 at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2625) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2603) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3237) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3194) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3163) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3136) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3113) at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3106) at com.magazineservice.magazineservice/pkg.magazineservice.home_controller.initialize(home_controller.java:40) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466) at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:2435) at com.magazineservice.magazineservice/pkg.magazineservice.HelloApplication.start(HelloApplication.java:25) at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:846) at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:455) at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428) at java.base/java.security.AccessController.doPrivileged(Native Method) at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427) at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96) at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174) at java.base/java.lang.Thread.run(Thread.java:829) Caused by: java.lang.NullPointerException at javafx.fxml/com.sun.javafx.fxml.expression.Expression.lambda$multiply$2(Expression.java:928) at javafx.fxml/com.sun.javafx.fxml.expression.BinaryExpression.evaluate(BinaryExpression.java:55) at javafx.fxml/com.sun.javafx.fxml.expression.ExpressionValue.getValue(ExpressionValue.java:192) at javafx.base/com.sun.javafx.binding.ExpressionHelper.addListener(ExpressionHelper.java:53) at javafx.base/javafx.beans.value.ObservableValueBase.addListener(ObservableValueBase.java:55) at javafx.fxml/com.sun.javafx.fxml.expression.ExpressionValue.addListener(ExpressionValue.java:201) at javafx.base/javafx.beans.binding.DoubleBinding.bind(DoubleBinding.java:152) at javafx.base/javafx.beans.property.DoublePropertyBase$ValueWrapper.<init>(DoublePropertyBase.java:277) at javafx.base/javafx.beans.property.DoublePropertyBase$2.<init>(DoublePropertyBase.java:182) at javafx.base/javafx.beans.property.DoublePropertyBase.bind(DoublePropertyBase.java:182) at javafx.graphics/javafx.css.StyleableDoubleProperty.bind(StyleableDoubleProperty.java:75) at javafx.fxml/javafx.fxml.FXMLLoader$Element.processPropertyAttribute(FXMLLoader.java:326) at javafx.fxml/javafx.fxml.FXMLLoader$Element.processInstancePropertyAttributes(FXMLLoader.java:242) at javafx.fxml/javafx.fxml.FXMLLoader$ValueElement.processEndElement(FXMLLoader.java:775) at javafx.fxml/javafx.fxml.FXMLLoader.processEndElement(FXMLLoader.java:2838) at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2557) ... 21 more

Answer 1

感谢@James_D 的评论，他指出prefWidth和prefHeight是问题所在。 只需从view.fxml删除这些行即可解决我的问题。

解决方案：

<VBox xmlns="http://javafx.com/javafx/8"
 xmlns:fx="http://javafx.com/fxml/1"
 fx:id="View"
 alignment="CENTER"
 fx:controller="pkg.magazineservice.view_controller"
 >
<!-- NO WIDTH AND HEIGHT-->