How to get controller of scene in JavaFx8?

Question

I use several scenes and currently there are one method for each scene, like

  void setScene1() {
    FXMLLoader loader = new FXMLLoader(getClass().getResource("/main2.fxml"));
    Parent root = FXMLLoader.load();
    Scene scene = new Scene(root);
    loader.<Controller1>getController().callMethod();
    primaryStage.setScene(scene);

  }

but I want to remember Scene and do it like that

  void setScene1() {
    FXMLLoader loader = scene1.getLoaderSomehow(); // < ---- ????
    loader.<Controller1>getController().callMethod();
    primaryStage.setScene(scene1);

  }

Answer 1

This could be done using Scene.getUserData and Scene.setUserData:

...
Scene scene = new Scene(root);
scene.setUserData(loader);

FXMLLoader loader = (FXMLLoader) scene.getUserData();

But you should keep the following in mind:

• You use the loader only to get the controller. The loader could contain references to objects that could be garbage collected otherwise. Consider keeping a reference to the controller instead.
• Any other place would be more convenient (and depending on the approach more typesafe). You're "remembering" the Scene, so why not "remember" the loader/controller too?