Move a circle using arrow keys - Java

Question

I'm experimenting with JavaFX right now teaching myself how to move text and items using the arrow keys. I made a program that simply moves text around the stage if an arrow key is pressed down.

I would like to make a circle move around my pane instead of text. What changes must I make to move my circle using the arrow keys?

public void start(Stage primaryStage) {
        Pane pane = new Pane();

        int dx = 50;
        int dy = 50;
        int radius = 125;

        Circle circle = new Circle(radius,dx,dy);
        Text text = new Text(20,20,"HI");
        circle.setFill(Color.WHITE);
        circle.setStroke(Color.BLACK);

        pane.getChildren().addAll(circle, text);

        circle.setOnKeyPressed(e -> {
            switch(e.getCode()) {
            case DOWN: text.setY(text.getY() + 10);
            break;
            case UP: text.setY(text.getY() - 10);
            break;
            case LEFT: text.setX(text.getX() - 10);
            break;
            case RIGHT: text.setX(text.getX() + 10);
            break;
            default:
                if(Character.isLetterOrDigit(e.getText().charAt(0)))
                    text.setText(e.getText());
            break;      
            }
        });

        Scene scene = new Scene(pane, 250, 200);
        primaryStage.setTitle("Arrow Keys");
        primaryStage.setScene(scene);
        primaryStage.show();

        text.requestFocus();
    }

Answer 1

scene.setOnKeyPressed(e -> {
    switch (e.getCode()) {
    case DOWN:
        circle.setCenterY(circle.getCenterY() + 10);
        break;
    case UP:
        circle.setCenterY(circle.getCenterY() - 10);
        break;
    case LEFT:
        circle.setCenterX(circle.getCenterX() - 10);
        break;
    case RIGHT:
        circle.setCenterX(circle.getCenterX() + 10);
        break;
    }
});

Answer 2

Personally, I would change where you are listening for the key press. I would put it on the Pane, because it is always in focus in this example. Other than that, you may have to remove and readd the circle if you didnt want the last one to stay, I'm not at my computer so I cant confirm this, but resulting code would look like this.

public void start(Stage primaryStage) {
        Pane pane = new Pane();

        int dx = 50;
        int dy = 50;
        int radius = 125;

        Circle circle = new Circle(radius,dx,dy);
        Text text = new Text(20,20,"HI");
        circle.setFill(Color.WHITE);
        circle.setStroke(Color.BLACK);

        pane.getChildren().addAll(circle, text);

        pane.setOnKeyPressed(e -> {
            pane.getChildren().remove(circle);
            switch(e.getCode()) {
            case DOWN: circle.setCenterY(circle.getCenterY() + 10);
            break;
            case UP: circle.setCenterY(circle.getCenterY() - 10);
            break;
            case LEFT: circle.setCenterX(circle.getCenterX() + 10);
            break;
            case RIGHT: circle.setCenterX(circle.getCenterX() - 10);
            break;    
            }
            pane.getChildren().add(circle);
        });

        Scene scene = new Scene(pane, 250, 200);
        primaryStage.setTitle("Arrow Keys");
        primaryStage.setScene(scene);
        primaryStage.show();
    }