如何在JavaFX中创建自定义加载屏幕？

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class LoadingScreen extends Application {

    @Override
    public void start(Stage primaryStage) {
        // 创建一个进度条
        ProgressBar progressBar = new ProgressBar();
        progressBar.setPrefWidth(300);

        // 将进度条放在一个StackPane布局中
        StackPane root = new StackPane();
        root.getChildren().add(progressBar);

        // 创建一个场景
        Scene scene = new Scene(root, 300, 150);

        primaryStage.setTitle("Loading Screen");
        primaryStage.setScene(scene);
        primaryStage.show();

        // 模拟加载过程
        Thread thread = new Thread(() -> {
            try {
                for (int i = 0; i <= 100; i++) {
                    Thread.sleep(50);
                    progressBar.setProgress(i / 100.0);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });
        thread.start();
    }

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