Javafx Not on fx application thread when using timer

Question

I\'m using this

import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;

import javafx.application.Application;
import javafx.applicatio         


        

Answer 1

It may be because you misunderstood how Platform.runLater() works..

The correct code snippet would be:

public void moveCircle(Circle circle, Scene scene) {
    Timer timer = new Timer();
    timer.scheduleAtFixedRate(new TimerTask() {
        @Override
        public void run() {
            Platform.runLater(() -> {
                circle.setCenterX(random((int) scene.getX()));
                circle.setCenterY(random((int) scene.getY()));
            });
        }
    }, 1000, 1000);
}

But:

I would strongly recommend you to not use Timer but TimeLine instead! It is part of the JavaFX API and you do not have to do these Platform.runLater() calls. This is just quickly hacked together, but you get the idea:

public void moveCircle(Circle circle, Scene scene) {
    Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(1), ev -> {
        circle.setCenterX(random((int) scene.getX()));
        circle.setCenterY(random((int) scene.getY()));
    }));
    timeline.setCycleCount(Animation.INDEFINITE);
    timeline.play();
}