使用和更新Canvas节点的JavaFX 8.0 Scene Builder 2.0

Question

so i am using SceneBuilder 2.0 to create a stage with a Canvas node and then use the ContextGraphics of the Canvas to modify it from the controller file, is this possible? i read that the Canvas can be modified before it is attached to a Stage from any thread, but if its already been attached to a stage it has to be modified by the JavaFX application thread or else you will find problems like the Canvas not updating (which is exactly what is happening to me).

I currently have this code which is not working:

in the JavaFX Application:

@Override
public void start(Stage stage) throws Exception {
    Parent root = FXMLLoader.load(getClass().getResource("Window.fxml"));

    Scene scene = new Scene(root);

    stage.setScene(scene);
    stage.show();
}

And in the controller file:

@FXML
private Canvas canvas;

public void render() {
    GraphicsContext gc = canvas.getGraphicsContext2D();
    Image image1 = new Image("/img/Test1.png");
    gc.drawImage(image1, 300, 300);
}

and then i call the method render() but the Canvas wont update, any ideas?

Answer 1

You are not telling us where and from which thread you are calling the render method. Anyway - I'd bet that your image has just not been loaded correctly. Check the error property of the image before you draw it.