Detect when stage again in focus and scene is loaded

Question

I have a parent stage, on top of which popup can be shown. Here is code:

private static Stage chooseBreedStage;
    static {
        chooseBreedStage = new Stage();
        chooseBreedStage.setTitle("Choose breed");
        chooseBreedStage.initOwner(AppKitty.getStage());
        chooseBreedStage.initModality(Modality.WINDOW_MODAL);
        chooseBreedStage.setScene(SceneManager.getInstance().getScene(SceneEnum.CHOOSE_BREED_SCREEN));
    }

    public void showChooseBreedPopup() {
        chooseBreedStage.showAndWait();
    }

Before I show popup, I blur the parent node by setEffect() method. How can I remove the blur effect when popup is closed?

In my attempts I always facing issue with despite popup already dissapear, elements annotated by @FXML in parent screen controller is null, but they alreadt visible and dont hidden by popup

Is there any listener, which handle events when stage not blocked and scene is already loaded, so I can interact with @FXML objects?

Here is part of scene controller which set in primary stage:

        public class MainScreenController {
        private GaussianBlur blur = new GaussianBlur();
            @FXML
            public StackPane mainScreen;
        
            public void blurOn() {
                mainScreen.setEffect(blur);
            }
            public void blurOff() {
                mainScreen.setEffect(null);
            }
        public void makeTestClick(ActionEvent event) {
            blurOn();
           SceneManager.getInstance().getController(ChooseBreedScreenController.class)
                    .showChooseBreedPopup(); 
        }
    }

SceneManager class code(@Data is lombok annotation, can be replaced by getters ad setters):

public class SceneManager {
    private final Map<SceneEnum, SceneData> sceneData = new HashMap<>();

    @Data
    private class SceneData {
        private Scene scene;
        private FXMLLoader loader;
        private Controller controller;

        SceneData(Scene scene, FXMLLoader loader) {
            setScene(scene);
            setLoader(loader);
            setController(controller);
        }
    }

    private static SceneManager instance = new SceneManager();

    public static SceneManager getInstance() {
        return instance;
    }

    private SceneManager() {
    }

    public <T extends Controller> T getController(Class<T> controllerClass) {
        SceneEnum sceneEnum = getCorrespondingEnum(controllerClass);
        if (sceneData.get(sceneEnum) == null || sceneData.get(sceneEnum).getController() == null) {
            initSceneController(controllerClass);
        }
        return (T) sceneData.get(sceneEnum).getController();
    }

    public Controller getController(SceneEnum sceneEnum) {
        return getController(sceneEnum.getControllerClass());
    }

    private <T extends Controller> void initSceneController(Class<T> controllerClass) {
        try {
            SceneEnum sceneEnum = getCorrespondingEnum(controllerClass);
            if (sceneData.get(sceneEnum) == null) {
                initScene(sceneEnum);
            }
            sceneData.get(sceneEnum).setController(controllerClass.getConstructor().newInstance());
        } catch (Exception e) {
            //todo here should be popup with error
        }
    }

    private <T extends Controller> SceneEnum getCorrespondingEnum(Class<T> controllerClass) {
        Optional<SceneEnum> desiredSceneEnum = Arrays.stream(SceneEnum.values())
                .filter(sceneEnum -> controllerClass.isAssignableFrom(sceneEnum.getControllerClass()))
                .findFirst();
        return desiredSceneEnum.orElseGet(() -> {
            //todo here should be shown popup with error
            return null;
        });
    }

    public Scene getScene(SceneEnum sceneEnum) {
        if (sceneData.get(sceneEnum) == null) {
            initScene(sceneEnum);
        }
        return sceneData.get(sceneEnum).getScene();
    }

    private void initScene(SceneEnum sceneEnum) {
        ConsumerWithException<SceneEnum, IOException> loadingScene = sceneType -> {
            FXMLLoader loader = getFxmlLoader(sceneEnum);
            Scene scene = new Scene(loader.load());
            sceneData.put(sceneEnum, new SceneData(scene, loader));
        };
        try {
            loadingScene.accept(sceneEnum);
        } catch (IOException initializeScreenException) {
            try {
                //Loading app error popup scene, before calling getController() method for
                //this popup, to avoid recursion if loading app error popup scene producing exception as well
                //(it may be in initScene method inside getController method)
                loadingScene.accept(SceneEnum.APP_ERROR_POPUP);
                getController(AppErrorPopupController.class)
                        .showAppErrorPopup(sceneEnum);
            } catch (IOException initializeErrorPopupException) {
                //todo make a better logging
                initializeErrorPopupException.printStackTrace();
            }
        }
    }

    private FXMLLoader getFxmlLoader(SceneEnum scene){
        return new FXMLLoader(this.getClass().getResource(scene.getScenePath()));
    }
}

AppKitty class:

public class AppKitty extends Application {
    private static Stage stage;

    public static Stage getStage() {
        return stage;
    }

    public static void setScene(SceneEnum sceneEnum) {
        getStage().setScene(SceneManager.getInstance()
                        .getScene(sceneEnum));
    }

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

    @Override
    public void start(Stage primaryStage) {
        stage = primaryStage;
        primaryStage.setTitle("AppKitty");
        primaryStage.setScene(SceneManager.getInstance().getScene(SceneEnum.MAIN_SCREEN));
        primaryStage.show();
    }
}

mainScreen.fxml :

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<?import javafx.geometry.Insets?>
<StackPane xmlns="http://javafx.com/javafx"
           xmlns:fx="http://javafx.com/fxml"
           fx:controller="applicationinterface.controllers.MainScreenController"
           prefHeight="400.0" prefWidth="600.0"
           fx:id="mainScreen"
           stylesheets="@../styles/mainScreenBackground.css"
           id="background_image">

    <Label fx:id="title" text="What do you want?" alignment="TOP_CENTER"
           stylesheets="@../styles/outline.css" styleClass="outline" StackPane.alignment="TOP_CENTER">

    </Label>
    <HBox
            fx:id="bottomBar" id="outline.label" alignment="BOTTOM_CENTER"
            stylesheets="@../styles/outline.css" spacing="20" StackPane.alignment="BOTTOM_CENTER">
        <StackPane.margin>
            <Insets bottom="10"/>
        </StackPane.margin>
        <Button fx:id="randomKittyButton" text="Random Kitty" onAction="#randomKittyClick" focusTraversable="false"
                stylesheets="@../styles/buttonBorder.css" styleClass="button"/>
        <Button fx:id="makeTestButton" text="Take the test" onAction="#makeTestClick" focusTraversable="false"
                stylesheets="@../styles/buttonBorder.css" styleClass="button"/>
    </HBox>
</StackPane>

Answer 1

As per your code, you need to include the close handlers for the popup stage at the time of declaration in your static block. You can include any of the below handlers.. (depends as per your need)

chooseBreedStage.setOnCloseRequest(e1->{
    // Remove blur of AppKitty.getStage()
});

chooseBreedStage.addEventHandler(WindowEvent.WINDOW_HIDDEN,e1->{
    // Remove blur of AppKitty.getStage()
});

chooseBreedStage.addEventFilter(WindowEvent.WINDOW_CLOSE_REQUEST,e1->{
    // Remove blur of AppKitty.getStage()
});