inheritance - 从不扩展 Application 的类的 Main 方法启动 JavaFX

Question

我在从不扩展javafx.application.Application的类的Main方法启动JavaFX应用程序时遇到问题

在我的应用程序中，有一个 MainApp.java ，它应该启动 MainUIController.java 中的重写方法 start() ，该方法扩展了申请

当我从 MainUIController.java 启动 Main 方法时，一切正常。

MainApp.java

public class MainApp {

    public static void main(String[] args) {
        PersonJDBCTemplate jdbc = connect();
        MainUIController mUIc = new MainUIController(jdbc);
        mUIc.start(new Stage());

    }

    public static PersonJDBCTemplate connect() {
        ApplicationContext context = new ClassPathXmlApplicationContext(
                "Beans.xml");
        PersonJDBCTemplate personJDBCTemplate = (PersonJDBCTemplate) context
                .getBean("personJDBCTemplate");
        return personJDBCTemplate;
    }
}

MainUIController.java

public class MainUIController extends Application {

    private Stage stage;
    // private User loggedUser;
    private final double MINIMUM_WINDOW_WIDTH = 800.0;
    private final double MINIMUM_WINDOW_HEIGHT = 570.0;
    private String version = "0.6";
    private PersonJDBCTemplate jdbc;

    public MainUIController(PersonJDBCTemplate jdbc) {
        this.jdbc = jdbc;

    }

    @Override
    public void start(Stage primaryStage) {
        try {
            stage = primaryStage;
            stage.setTitle("Sharp");
            stage.setMinWidth(MINIMUM_WINDOW_WIDTH);
            stage.setMinHeight(MINIMUM_WINDOW_HEIGHT);
            stage.setResizable(false);
            gotoLogin();
            primaryStage.show();
        } catch (Exception ex) {
            Logger.getLogger(MainUIController.class.getName()).log(
                    Level.SEVERE, null, ex);
        }
    }

    public void gotoLogin() {
        try {
            LoginController login = (LoginController) replaceSceneContent("/fxml/Login.fxml");
            login.setApp(this);
        } catch (Exception ex) {
            Logger.getLogger(MainUIController.class.getName()).log(
                    Level.SEVERE, null, ex);
        }
    }
}

运行MainApp后，我收到以下错误:

Exception in thread "main" java.lang.ExceptionInInitializerError
at javafx.stage.Window.<init>(Window.java:1110)
at javafx.stage.Stage.<init>(Stage.java:236)
at javafx.stage.Stage.<init>(Stage.java:224)
at ch.kit.sharp.main.MainApp.main(MainApp.java:15)
Caused by: java.lang.IllegalStateException: This operation is permitted on the event thread only; currentThread = main
at com.sun.glass.ui.Application.checkEventThread(Application.java:445)
at com.sun.glass.ui.Screen.setEventHandler(Screen.java:245)
at com.sun.javafx.tk.quantum.QuantumToolkit.setScreenConfigurationListener(QuantumToolkit.java:600)
at javafx.stage.Screen.<clinit>(Screen.java:80)
... 4 more

Answer 1

除了Nejinx所说的之外，你不能直接调用你的start()，总是调用launch() ，因为它设置了JavaFX环境，包括创建阶段和调用start()将阶段作为参数传递给它。

The docs有一个注释专门说明了这一点

NOTE: This method is called on the JavaFX Application Thread

launch()可以从任何类调用，考虑到该类是否直接扩展 javafx.application.Application ，那么您必须将扩展它的类作为参数传递给启动方法。

例如，假设您有一个类 JavaFXMain ，它扩展了 Application

class JavaFXMain extends Application {...}

您可以使用任何其他类来启动 JavaFX 应用程序。

class Main {
   ...
   public void someMethod() {
      ...
      JavaFXMain.launch(JavaFXMain.class); // Launch the JavaFX application
      ...
   }
}

就您而言，您可以在 MainApp 的 main 方法中尝试类似的操作:

// You may remove args if you don't intend to pass any arguments
MainUIController.launch(MainUIController.class, args)