java - 如何在javaFx中的应用程序窗口之前制作加载场景？

Question

我试图在真正的应用程序窗口打开之前创建一个加载窗口。加载场景中有一个进度条，并且是不确定的。

问题是；直到我执行程序时真正的窗口打开时，进度条才起作用。

顺便说一句，我尝试了预加载器类，但也不起作用。

这是我的代码；

public class MainApp2 extends Application {


    private Stage loadingStage = new Stage();

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


    public void start(final Stage mainStage) throws Exception {

        //loading..
        loadingScreen();

        //start...
        appScreen();

    }


    private void loadingScreen() {

        ProgressBar bar = new ProgressBar(ProgressIndicator.INDETERMINATE_PROGRESS);
        bar.setPrefWidth(300);
        bar.setPrefHeight(200);

        loadingStage.initStyle(StageStyle.TRANSPARENT);
        loadingStage.initStyle(StageStyle.UNDECORATED);
        loadingStage.setScene(new Scene(bar));
        loadingStage.show();

    }


    private void appScreen() {

        new Task<Void>() {
            @Override
            protected Void call() throws Exception {

                Stage mainStage = new Stage();

                //get real window
                Scene root = new Scene(new MyAppWindow().getAppWindow());
                mainStage.setScene(root);
                mainStage.centerOnScreen();
                mainStage.show();

//                loadingStage.close();

                return null;
            }
        }.run();

    }

    public class MyAppWindow {

        public BorderPane getAppWindow(){

            System.out.println("may be initialize take a long time...");
            for (int i = 0; i < 90000000; i++) {
                System.out.print("");
            }

            return new BorderPane(new Label("Here is real application Window!"));
        }


    }


}

Answer 1

您可以使用预加载器。这是一个例子。取自source

public class FirstPreloader extends Preloader {
    ProgressBar bar;
    Stage stage;

    private Scene createPreloaderScene() {
        bar = new ProgressBar();
        BorderPane p = new BorderPane();
        p.setCenter(bar);
        return new Scene(p, 300, 150);        
    }

    public void start(Stage stage) throws Exception {
        this.stage = stage;
        stage.setScene(createPreloaderScene());        
        stage.show();
    }

    @Override
    public void handleProgressNotification(ProgressNotification pn) {
        bar.setProgress(pn.getProgress());
    }

    @Override
    public void handleStateChangeNotification(StateChangeNotification evt) {
        if (evt.getType() == StateChangeNotification.Type.BEFORE_START) {
            stage.hide();
        }
    }    
}