Placing circles in a pane with javafx - javafx

Question

Trying to create dynamically a series of circles with Javafx. After typing the number of circles i got this:
But actually i want that my circles be in that position:
Here is my code and thanks for any hints!!
int k = 5;
for (int i = 0; i < nbNoeuds; i++) {
Noeudfx circle = new Noeudfx(k * 2, k * 2, 1, String.valueOf(i));
Label id = new Label(String.valueOf(i));
noeuds.getChildren().add(id);
id.setLayoutX(k * 2 - 20);
id.setLayoutY(k * 2 - 20);
id.setBlendMode(BlendMode.DIFFERENCE);
k += 10;
FillTransition ft1 = new FillTransition(Duration.millis(300), circle, Color.RED, Color.BLACK);
ft1.play();
noeuds.getChildren().add(circle);
ScaleTransition tr = new ScaleTransition(Duration.millis(100), circle);
tr.setByX(10f);
tr.setByY(10f);
tr.setInterpolator(Interpolator.EASE_OUT);
tr.play();
}
}
public class Noeudfx extends Circle {
Noeud noeud;
Point point;
Label distance = new Label("distance : infinite");
boolean isSelected = false;
List<Noeudfx> circles = new ArrayList<>();
public Noeudfx(double a, double b, double c, String nom) {
super(a, b, c);
noeud = new Noeud(nom, this);
point = new Point((int) a, (int) b);
circles.add(this);
}
}

Answer 1

Here is my solution:
int nbNoeuds = Integer.parseInt(nodeID.getText());
System.out.println("nnnnn"
+ nbNoeuds);
final Timeline animation = new Timeline(
new KeyFrame(Duration.seconds(.5), (ActionEvent actionEvent) -> {
while (noeuds.getChildren().size() <= nbNoeuds) {
// noeuds.getChildren().remove(0);
int radius =10 ;
noeuds.getChildren().add(
new Circle(
rnd.nextInt(SCENE_SIZE - radius * 2) + radius, rnd.nextInt(SCENE_SIZE - radius * 2) + radius,
radius,
Color.GRAY
)
);
}
})
);
animation.setCycleCount(Animation.INDEFINITE);
animation.play();
animation.setOnFinished((ActionEvent actionevent) -> {
animation.stop();
});
Update: i tried to add label to each circle, the problem was that the number of circles in the screen is not correct i don't know why!
Label id = new Label(String.valueOf(i));
id.setTextFill(Color.CADETBLUE);
id.setAlignment(Pos.CENTER);
Circle circle = new Circle(
rnd.nextInt(SCENE_SIZE - radius * 2) + radius, rnd.nextInt(SCENE_SIZE - radius * 2) + radius,
radius,
Color.GRAY
);
Double a = circle.getCenterX();
Double b = circle.getCenterY();
id.setLayoutX(a - 20);
id.setLayoutY(b - 20);
id.setBlendMode(BlendMode.DIFFERENCE);
noeuds.getChildren().add(id);
noeuds.getChildren().add(circle);