JavaFX update bullet position UI in a loop

Question

For my school project i have to make a game where a cannon have to shoot a bullet to a airplane, the problem is, when we shoot we can see all the position (X . Y) of the bullet on console but the bullet doesn't update on the UI

Here's the Test code:

vel = Slider.getValue();
double angle = panelNero.getRotate();
boolean dead = false;

while (dead == false) {
    double X = P.getLayoutX();
    double Y = P.getLayoutY();
    if (X > 1 && Y > 1 && X < MP.getWidth() && Y < MP.getHeight()) {
        System.out.println("x: " + X + " y: " + Y + " maxX: " + MP.getWidth() + " maxY: " + MP.getHeight());

        double x = P.getLayoutX();
        double y = P.getLayoutY();
        P.setLayoutX(x += (Math.cos(Math.toRadians(angle)) * vel));
        P.setLayoutY(y += (Math.cos(Math.toRadians(angle)) * vel));
        System.out.println("VIVO");
        try {
            TimeUnit.MILLISECONDS.sleep(500);
        } catch (InterruptedException ex) {
            Logger.getLogger(FileFXMLController.class.getName()).log(Level.SEVERE, null, ex);
        }
    } else {
        System.out.println("MORTO");

        P.setLayoutX(pro.posX);
        P.setLayoutY(pro.posY);
        dead = true;
    }
}

Possible duplicate of [JavaFX periodic background task](http://stackoverflow.com/questions/9966136/javafx-periodic-background-task) — fabian, May 10 '16 at 17:12

score 0 · Accepted Answer · edited May 23 '17 at 12:07

Please take a look at this post: Platform.runLater and Task in JavaFX

You can use Platform.runlater() to update your GUI from a non-GUI thread. In this case, your update request is put in a queue and handled by the GUI thread ASAP.

But since this is a more complex iteration, you can consider using a Task on a new Thread.

I suggest you to use something like this:

Task task = new Task<Void>() {
    @Override
    public Void call() throws Exception {
        while (dead == false) {
            Platform.runLater(new Runnable() {
                @Override
                public void run() {
                    P.setLayoutX(...);
                    P.setLayoutY(...);
                }
            });
            Thread.sleep(500);
        }
    }
};
Thread th = new Thread(task);
th.start();

JavaFX update bullet position UI in a loop

1 Answers1