How can I show a random light with a traffic light?

Question

I am a beginner with programming and coding. I try to make random things to develop myself. I drawed a traffic light with JavaFX. Now I want to when I click on the button a random light will glow.

I've tried it with a switch and else elseif. I did not come to a solution

public StoplichtLayout(Pane l){
    layout = l;
    layout.setStyle("-fx-background-color: #777;");

    button = new Button("Teken");
    button.setLayoutX(10);
    button.setLayoutY(10);
    button2 = new Button("Random licht laten branden");
    button2.setLayoutX(100);
    button2.setLayoutY(10);

    button.setOnAction(ev -> {
        button();
    });
    this.layout.getChildren().add(button);

    button2.setOnAction(ev -> {

    });
    this.layout.getChildren().add(button2);
}
private void button(){

    Rectangle paal = new Rectangle(200, 300, 25, 200);

    paal.setArcHeight(10);
    paal.setArcHeight(10);

    Rectangle bord = new Rectangle();
    bord.setX(175);
    bord.setY(175);
    bord.setWidth(75);
    bord.setHeight(150);
    bord.setFill(Color.GREY);
    bord.setStroke(Color.BLACK);
    bord.setArcHeight(20);
    bord.setArcWidth(20);

    Circle roodlicht = new Circle(15);
    roodlicht.setCenterX(213);
    roodlicht.setCenterY(205);
    roodlicht.setFill(Color.rgb(165, 0, 0));
    roodlicht.setStroke(Color.BLACK);

    Circle geellicht = new Circle(15);
    geellicht.setCenterX(213);
    geellicht.setCenterY(250);
    geellicht.setFill(Color.rgb(188, 173, 54));
    geellicht.setStroke(Color.BLACK);

    Circle groenlicht = new Circle(15);
    groenlicht.setCenterX(213);
    groenlicht.setCenterY(295);
    groenlicht.setFill(Color.rgb(9, 114, 0));
    groenlicht.setStroke(Color.BLACK);



    layout.getChildren().addAll(paal, bord, roodlicht, geellicht, groenlicht);
}

}

I expect that when I click on the button a random light will glow. I hope somebody can help me.

Answer 1

You expect that to happen yet you have no code there. Put your circles in an indexed collection such as an ArrayList then find a random one and light it up by lightening the color as below:

List<Circle> lights = new ArrayList<Circle>();
// add your circles to the list
Circle toLight = lights.get(new Random().nextInt(lights.size()));
// V setting the color to be brighter
toLight.setFill(((Color) toLight.getFill()).brighter());