When to connect event handlers in JavaFX if event targets appear dynamically?

Question

Java

The program has a panel with buttons, which initially looks like this:

When the program starts, I use the method attachMonitoringEvents(), which, as planned, should register all event handlers in the program:

public ControllerMonitoringEnvironment(MonitoringEnvironment monitoringEnvironmentModel,MonitoringEnvironmentView monitoringEnvironmentView) {
        this.monitoringEnvironmentModel = monitoringEnvironmentModel;
        this.monitoringEnvironmentView = monitoringEnvironmentView;
        attachMonitoringEvents();
    }

Button addImageForActivityButton;
TextField nameOfActivityTextField;

    public void attachMonitoringEvents() {
            monitoringEnvironmentView.getAddActivityButton()
            .setOnMouseClicked(new EventHandler<MouseEvent>() {
                @Override
                public void handle(MouseEvent event) {
                    System.out.println("Создать активность");


                    addImageForActivityButton =  new Button();

                    //...//

                    FileChooser fileChooser = new FileChooser();
                    fileChooser.setTitle("Выбор изображения для активности");

                    addImageForActivityButton.setOnAction(
                            new EventHandler<ActionEvent>() {
                                @Override
                                public void handle(ActionEvent event) {
                                    configureFileChooser(fileChooser);
                                    File file = fileChooser.showOpenDialog(stage);
                                    if (file != null) {
                                        openFile(file);
                                        attachActivityPanelsEvents();
                                        createAddActivityPanel(file);
                                    }
                                }
                            }
                    );
                }
            });


        }

This method registers a button click event handler with a plus sign.
Click on the plus button. Result:

There is a button to add an image.
The button handler for adding an image is declared in the button handler with a plus sign.
Selected image:

The "OK" button appeared. We connected the "OK" button handler:

private void createAddActivityPanel(File file) {

      
        Button okChooseImageButton = new Button("OK");

       // okChooseImageButton.addEventHandler(MouseEvent.MOUSE_CLICKED,addActivityHandler);


    }

    private  void attachActivityPanelsEvents() {
            EventHandler<MouseEvent> addActivityHandler =
                    new EventHandler<MouseEvent>() {

                        @Override
                        public void handle(MouseEvent event) {
                            System.out.println("Add activity");

                        }
                    };

            nameOfActivityTextField.setOnKeyPressed(
                new EventHandler<KeyEvent>() {
                    @Override
                    public void handle(KeyEvent keyEvent) {
                        if (keyEvent.getCode() == KeyCode.ENTER) {
                            System.out.println("Add activity");


                        }
                    }
                }
        );
    }

I want addActivityHandlerto include in the method createAddActivityPanel().
Is it possible and reasonable to create/hook an event handler in another event handler?
How to correctly connect and disconnect event handlers in JavaFX if elements are added dynamically?

Answer 1

And what is the sacred meaning of poking around and creating heaps of handlers? Judging by the code, you have exactly the same result, i.e.
1) Pressed the plus sign, a picture button appeared
2) Pressed the picture button, selected a picture, the "ok" button appeared
3) The "ok" button does System.out.println("Add activity");
It follows that there is no point in fussing like that either, because it's easier to go other ways =) Which ones I recommend to think about with your own brains. I’ll just give you a hint, classes can be overridden and inherited, you can store a link to the selected object and dance from it, you can declare an EventHandler and simply give a link to the necessary components and not create and produce heaps of EventHandlers.