JavaFX 異常“應用程序啟動方法中的異常”僅在我使用 Scene Builder 添加 id 和 onAction 之后

Question

我有一個項目，我在 Scene Builder 上創建 GUI。 當我第一次創建我的 GUI 的所有元素時，它工作得很好。 但是，一旦我將 ids 和 onActions 添加到我的 textFields 和其他元素中，它就會破壞代碼，提示“應用程序啟動方法中存在異常”。 我不確定如何處理這個問題，因為我一直在對其他項目做完全相同的事情，而這以前從未發生過。

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="500.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/18" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <ListView fx:id="eventListView" layoutX="239.0" layoutY="60.0" prefHeight="380.0" prefWidth="348.0">
         <contextMenu>
            <ContextMenu>
              <items>
                <MenuItem mnemonicParsing="false" text="Details" />
                  <MenuItem mnemonicParsing="false" text="Remove" />
              </items>
            </ContextMenu>
         </contextMenu>
      </ListView>
      <TextField fx:id="titleTextField" layoutX="46.0" layoutY="101.0" />
      <TextField fx:id="descriptionTextField" layoutX="46.0" layoutY="166.0" />
      <DatePicker fx:id="datePickerField" layoutX="40.0" layoutY="238.0" />
      <ComboBox fx:id="cmbAddType" layoutX="47.0" layoutY="295.0" onAction="#selectedType" prefWidth="150.0" />
      <Button fx:id="addEventButton" layoutX="72.0" layoutY="365.0" mnemonicParsing="false" onAction="#handleAddEvent" prefHeight="30.0" prefWidth="100.0" text="Add" />
      <ComboBox fx:id="cmbOrderFilter" layoutX="614.0" layoutY="153.0" onAction="#orderList" prefWidth="150.0" />
      <ComboBox fx:id="cmbTypeFilter" layoutX="614.0" layoutY="208.0" onAction="#filterType" prefWidth="150.0" />
      <Button fx:id="removeButton" layoutX="648.0" layoutY="257.0" mnemonicParsing="false" onAction="#handleRemoveEvent" prefHeight="30.0" prefWidth="100.0" text="Remove" />
      <Label layoutX="109.0" layoutY="74.0" text="Title" />
      <Label layoutX="88.0" layoutY="148.0" text="Description" />
      <Label layoutX="108.0" layoutY="213.0" text="Date" />
      <Label layoutX="108.0" layoutY="272.0" text="Type" />
      <Label layoutX="673.0" layoutY="127.0" text="Order" />
      <Label layoutX="675.0" layoutY="183.0" text="Type" />
      <Label layoutX="381.0" layoutY="25.0" text="Events List" />
   </children>
</AnchorPane>

public class MainWindow {

    @FXML
    private ResourceBundle resources;

    @FXML
    private URL location;

    @FXML
    private Button addEventButton;

    @FXML
    private ComboBox<?> cmbAddType;

    @FXML
    private ComboBox<?> cmbOrderFilter;

    @FXML
    private ComboBox<?> cmbTypeFilter;

    @FXML
    private DatePicker datePickerField;

    @FXML
    private TextField descriptionTextField;

    @FXML
    private ListView<?> eventListView;

    @FXML
    private Button removeButton;

    @FXML
    private TextField titleTextField;

    @FXML
    void filterType(ActionEvent event) {

    }

    @FXML
    void handleAddEvent(ActionEvent event) {

    }

    @FXML
    void handleRemoveEvent(ActionEvent event) {

    }

    @FXML
    void orderList(ActionEvent event) {

    }

    @FXML
    void initialize() {
        assert this.addEventButton != null : "fx:id=\"addEventButton\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.cmbAddType != null : "fx:id=\"cmbAddType\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.cmbOrderFilter != null : "fx:id=\"cmbOrderFilter\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.cmbTypeFilter != null : "fx:id=\"cmbTypeFilter\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.datePickerField != null : "fx:id=\"datePickerField\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.descriptionTextField != null : "fx:id=\"descriptionTextField\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.eventListView != null : "fx:id=\"eventListView\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.removeButton != null : "fx:id=\"removeButton\" was not injected: check your FXML file 'MainWindow.fxml'.";
        assert this.titleTextField != null : "fx:id=\"titleTextField\" was not injected: check your FXML file 'MainWindow.fxml'.";

    }

}

public class Main extends Application {
    private static final String WINDOW_TITLE = "Bulletin Board";
    private static final String GUI_RESOURCE = "view/MainWindow.fxml";

    /**
     * JavaFX entry point.
     *
     * @precondition none
     * @postcondition none
     *
     * @throws IOException
     */
    @Override
    public void start(Stage primaryStage) throws IOException {
        Parent parent = FXMLLoader.load(getClass().getResource(Main.GUI_RESOURCE));
        Scene scene = new Scene(parent);
        primaryStage.setTitle(WINDOW_TITLE);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    /**
     * Primary Java entry point.
     *
     * @precondition none
     * @postcondition none
     *
     * @param args command line arguments
     */

    public static void main(String[] args) {
        Main.launch(args);
    }

}

Exception in Application start method java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77 ) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:568) at javafx.graphics@18.0. 1/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:465) at javafx.graphics@18.0.1/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:364) at java. base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0（本機方法）位於 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:77） at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:568) at java.base/sun.launcher .LauncherHelper$FXHelper.main(LauncherHelper.java:1082) 原因：java.lang.RuntimeException：javafx.graphics@18.0.1/com.sun.883603413301888.graphics@18.0.1/com.sun.883603413301888.application(application) java:901) at javafx.graphics@18.0.1/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:196) at java.base/java.lang.Thread.run(Thread.java ：833）引起：javafx.fxml.LoadException：沒有指定controller。 /C:/Users/vvhs1/OneDrive/Documents/UWG/2022/Fall%202022/CS1302/Project3/BulletinBoardRepo/BulletinBoard/bin/edu/westga/cs1302/bulletin_board/view/MainWindow.fxml:28

at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2703) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader$Element.getControllerMethodHandle(FXMLLoader.java:568) at javafx .fxml@18.0.1/javafx.fxml.FXMLLoader$Element.processEventHandlerAttributes(FXMLLoader.java:610) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader$ValueElement.processEndElement(FXMLLoader.java:781) at javafx .fxml@18.0.1/javafx.fxml.FXMLLoader.processEndElement(FXMLLoader.java:2924) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2639) at javafx.fxml@18.0 .1/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3331) at javafx.fxml@18.0.1/javafx .fxml.FXMLLoader.loadImpl(FXMLLoader.java:3287) 在 javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.loadI mpl(FXMLLoader.java:3255) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3227) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader. java:3203) at javafx.fxml@18.0.1/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3196) at edu.westga.cs1302.bulletin_board.Main.start(Main.java:30) at javafx.graphics @18.0.1/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:847) 在 javafx.graphics@18.0.1/com.sun.javafx.application.And$WlamitImpl.PlatformImpl2$ PlatformImpl.java:484) at javafx.graphics@18.0.1/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457) at java.base/java.security.AccessController.doPrivileged(AccessController .java:399) 在 javafx.graphics@18.0.1/com.sun.javafx.application.PlatformImpl.lambda$runLater$ 11（PlatformImpl.java:456）javafx.graphics@18.0.1/com.sun.glass.ui.InvokeLaterDispatcher$Future.run（InvokeLaterDispatcher.java:96）javafx.ungraphics@1888.ungraphics@11 glass.ui.win.WinApplication._runLoop（本機方法）位於 javafx.graphics@18.0.1/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)... 1 更多異常運行應用程序 edu.westga.cs1302.bulletin_board.Main

我試過更改 JavaFX 版本，重新安裝 Scene Builder，但沒有用。 每次我刪除我的 FXML 文件上的所有組件並重建它時，它都會工作，直到我添加 ids 和 onAction。 正如我之前提到的，在過去的幾個月里，我一直在使用場景構建器並這樣做，但這種情況從未發生過。

Answer 1

錯誤消息告訴您出了什么問題：

Caused by: javafx.fxml.LoadException: No controller specified.

您需要將 controller 與 FXML 相關聯（如果您在 FXML 中提供使用 controller 的說明，例如，在 FXML 中設置操作處理程序）。

請參閱有關控制器的 FXML 文檔。

您可以通過在根元素中提供引用來在 FXML 中指定 controller（將 controller 名稱替換為控制器的完全限定名稱）：

fx:controller="com.foo.MyController"

SceneBuilder可以協助設置controller：

• 如何在場景生成器中設置 controller？

或者您可以在加載器上設置 controller 。

FXMLLoader loader = new FXMLLoader();
loader.setController(
    new MyController()
);

或者你可以使用controller 工廠，它通常與依賴注入框架一起使用，例如 Spring。