JavaFX Custom Component

flipper.fxml

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

<?import javafx.scene.layout.VBox?>
<?import javafx.scene.shape.Rectangle?>

<fx:root type="javafx.scene.layout.VBox" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/20.0.1">
   <Rectangle fx:id="flipper" arcHeight="5.0" arcWidth="5.0" fill="DODGERBLUE" height="200.0" strokeType="INSIDE" width="200.0" />
</fx:root>

Flipper.java

import javafx.animation.FillTransition;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.util.Duration;

import java.io.IOException;

public class Flipper extends VBox {
    @FXML
    private Rectangle flipper;

    private boolean state = false;

    public Flipper() {
        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource(
                "flipper.fxml"));
        fxmlLoader.setRoot(this);
        fxmlLoader.setController(this);

        try {
            fxmlLoader.load();
        } catch (IOException exception) {
            throw new RuntimeException(exception);
        }
        setupElements();
    }

    private void setupElements() {
        flipper.onMouseClickedProperty().set(event -> switchState());
    }

    private void switchState(){
        FillTransition ft;

        if (state){
            ft = new FillTransition(Duration.millis(1000), flipper, Color.RED, Color.BLUE);
            state = false;
        } else {
            ft = new FillTransition(Duration.millis(1000), flipper, Color.BLUE, Color.RED);
            state = true;
        }

        ft.setCycleCount(1);
        ft.play();
    }
}

HelloApplication.java

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;

import java.io.IOException;

public class HelloApplication extends Application {

    @Override
    public void start(Stage stage) throws IOException {
        FXMLLoader fxmlLoader = new FXMLLoader(HelloApplication.class.getResource("hello-view.fxml"));
        Scene scene = new Scene(fxmlLoader.load());
        stage.setTitle("Hello!");
        stage.setScene(scene);
        stage.show();
    }

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

HelloController.java

import javafx.fxml.FXML;
import javafx.scene.control.Label;

public class HelloController {
    @FXML
    private Label welcomeText;

    @FXML
    private Flipper flipper;


    @FXML
    protected void onHelloButtonClick() {
        welcomeText.setText("Welcome to JavaFX Application!");
    }
}