Makaveli Makaveli - 2 months ago 23
Java Question

JavaFX MousePosition

I need to get x and y coordinates of a mouseclick in my application. I partially solved it in the code below by creating a point but I keep getting different coordinates depending on where I move a window of my application on the screen. I would need something constant to identify certain obejcts later. Thank you for your help!

@Override
public void start(Stage stage) throws Exception {

final Pane root = new Pane();
setWidth(1400);
setHeight(1000);
Canvas background = new Canvas(getWidth(), getHeight());

final GraphicsContext context = background.getGraphicsContext2D();
File f = new File("background.png");
final Image image = new Image(new FileInputStream(f));

root.getChildren().add(background);


root.getChildren().add(b1);
b1.setLayoutX(1300);
b1.setLayoutY(10);


final Canvas animation = new Canvas(getWidth(), getHeight());
final Canvas animation2 = new Canvas(getWidth(), getHeight());

animation.setMouseTransparent(true);
animation2.setMouseTransparent(true);
final GraphicsContext context2 = animation.getGraphicsContext2D();
final GraphicsContext context3 = animation2.getGraphicsContext2D();

root.getChildren().add(animation);
root.getChildren().add(animation2);

Scene scene = new Scene(root, getWidth(), getHeight());

stage.setTitle("Old Gotham");
stage.setScene(scene);
stage.show();

final Duration oneFrameAmt = Duration.millis(1000 / 60);
final KeyFrame oneFrame;
oneFrame = new KeyFrame(oneFrameAmt,
new EventHandler() {
@Override
public void handle(Event event) {

context2.drawImage(image, 0, 0);
int offset = 700;

final Point p = MouseInfo.getPointerInfo().getLocation();

root.setOnMouseClicked(new EventHandler<Event>() {
@Override
public void handle(Event event) {
System.out.println(p.getX());
System.out.println(p.getY());
}
});

}
});
final Timeline tl = new Timeline(oneFrame);
tl.setCycleCount(Animation.INDEFINITE);
tl.play();
}


For the code presented by James_D, there is an error:

enter image description here

Answer

I don't understand why you are setting the mouse listener inside the listener for a key frame, but you need to get the coordinates from the mouse event.

MouseEvent defines getX() and getY() to get the coordinates of the mouse event relative to the node itself, getSceneX() and getSceneY() to get the coordinates of the mouse event relative to the whole Scene, and (in Java 8) getScreenX() and getScreenY() to get the coordinates of the mouse event relative to the entrie screen coordinate system.

So, if you're interested in the location of the mouse relative to the window (scene), do

root.setOnMouseClicked(new EventHandler<MouseEvent>() {
    @Override
    public void handle(MouseEvent event) {
        System.out.println(event.getSceneX());
        System.out.println(event.getSceneY());
    }
});