从不扩展应用程序的类的 Main 方法启动 JavaFX [英] Starting JavaFX from Main method of class which doesn't extend Application

问题描述

我在从不扩展 javafx.application.Application

在我的应用程序中有 MainApp.java，它应该在 MainUIController.java 中启动覆盖方法 start()，它扩展了应用

In my application there is the MainApp.java which should start the overriden method start() in the MainUIController.java, which extends Applciation

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

When I start the Main method from the MainUIController.java everything works fine.

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，出现以下错误:

After running the MainApp, I get the following Error :

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

推荐答案

除了 Nejinx 所说的，你千万不要直接调用你的 start()，总是调用 launch()，因为它设置了JavaFX环境，包括创建舞台和调用start()将舞台作为一个参数.

In addition to what Nejinx said, you must not directly call your start(), always call launch(), because it sets up the JavaFX environment, including creation of stage and calls start() passing the stage as an parameter to it.

文档有特别说明这一点的注释

The docs has a note specially stating this

注意:此方法在 JavaFX 应用程序线程上调用

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不扩展javafx.application.Application，那么你必须传递扩展它的类作为启动方法的参数.

The launch() can be called from any class, taking into consideration if the class is directly not extending javafx.application.Application, then you must pass the class extending it as an argument to the launch method.

例如，假设您有一个扩展 Application

For example, consider you have a class JavaFXMain which extends Application

class JavaFXMain extends Application {...}

您可以使用任何其他类来启动 JavaFX 应用程序.

You can use any other class, to start the JavaFX Application.

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

在你的情况下，你可以在 MainApp 的 main 方法中尝试这样的事情:

In your case, you can try something like this inside the main method of MainApp:

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

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