Timeline Events

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.animation.AnimationTimer;
import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.effect.Lighting;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.text.Text;
import javafx.util.Duration;
 
public class TimelineEvents extends Application {
 
    //main timeline
    private Timeline timeline;
    private AnimationTimer timer;
 
    //variable for storing actual frame
    private Integer i=0;
 
    @Override public void start(Stage stage) {
        Group p = new Group();
        Scene scene = new Scene(p);
        stage.setScene(scene);
        stage.setWidth(500);
        stage.setHeight(500);
        p.setTranslateX(80);
        p.setTranslateY(80);
 
        //create a circle with effect
        final Circle circle = new Circle(20,  Color.rgb(156,216,255));
        circle.setEffect(new Lighting());
        //create a text inside a circle
        final Text text = new Text (i.toString());
        text.setStroke(Color.BLACK);
        //create a layout for circle with text inside
        final StackPane stack = new StackPane();
        stack.getChildren().addAll(circle, text);
        stack.setLayoutX(30);
        stack.setLayoutY(30);
 
        p.getChildren().add(stack);
        stage.show();
 
        //create a timeline for moving the circle
        timeline = new Timeline();
        timeline.setCycleCount(Timeline.INDEFINITE);
        timeline.setAutoReverse(true);
 
//You can add a specific action when each frame is started.
        timer = new AnimationTimer() {
            @Override
            public void handle(long l) {
                text.setText(i.toString());
                i++;
            }
 
        };
 
        //create a keyValue with factory: scaling the circle 2times
        KeyValue keyValueX = new KeyValue(stack.scaleXProperty(), 2);
        KeyValue keyValueY = new KeyValue(stack.scaleYProperty(), 2);
 
        //create a keyFrame, the keyValue is reached at time 2s
        Duration duration = Duration.millis(2000);
        //one can add a specific action when the keyframe is reached
        EventHandler onFinished = new EventHandler<ActionEvent>() {
            public void handle(ActionEvent t) {
                 stack.setTranslateX(java.lang.Math.random()*200-100);
                 //reset counter
                 i = 0;
            }
        };
 
  KeyFrame keyFrame = new KeyFrame(duration, onFinished , keyValueX, keyValueY);
 
        //add the keyframe to the timeline
        timeline.getKeyFrames().add(keyFrame);
 
        timeline.play();
        timer.start();
    }
 
 
    public static void main(String[] args) {
        Application.launch(args);
    }
  }