Switching scenes the FXML way (SceneBuilder) - javafx-8

Question

I have two scenes, scene 1 has a Label on it that simply reads "This is scene 1", it also has a button on it with the text "Press me to go to scene 2". scene 2 is similar to scene 1 but the Label and text on scene 2 say the opposite.
The problem is very simple, or at least should be. I am able to do this the javaFX way but cannot seem to do it the FXML way.
I have a main class -
import java.io.IOException;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
public class ManinApp extends Application
{
Stage primaryStage;
private AnchorPane rootLayout;
public static void main(String [] args)
{
launch(args);
}
public void start(Stage primaryStage)
{
this.primaryStage = primaryStage;
this.primaryStage.setTitle("Two Scenes");
initRootLayout();
//showSecondScene();
}
public void initRootLayout()
{
try
{
FXMLLoader loader = new FXMLLoader();
loader.setLocation(ManinApp.class.getResource("Scene1.fxml"));
rootLayout = (AnchorPane) loader.load();
Scene scene = new Scene(rootLayout);
primaryStage.setScene(scene);
primaryStage.show();
}
catch(IOException e)
{
e.printStackTrace();
}
}
/**
public void showSecondScene()
{
try
{
FXMLLoader loader = new FXMLLoader();
loader.setLocation(ManinApp.class.getResource("Scene2.fxml"));
AnchorPane secondScene = (AnchorPane)loader.load();
rootLayout.getChildren().add(secondScene);
}
catch(IOException e)
{
e.printStackTrace();
}
}
*/
public Stage getPrimaryStage()
{
return primaryStage;
}
}
the showSecondScene() has been commented out for now. My understanding is that you also need a Controller class to wire up the code to SceneBuilder?
the solution the FX way was
btnscene1.setOnAction(e ->
{
if(e.getSource() == btnscene1)
thestage.setScene(scene2);
else
thestage.setScene(scene1);
});
btnscene2.setOnAction(e ->
{
if(e.getSource()==btnscene2)
thestage.setScene(scene1);
else
thestage.setScene(scene2);
});
apologies for the formatting!
how am I able to do this using a controller class from which i am able to use the primary stage and two scene declared in my main class?
i hope it makes sense

Answer 1

I think your are doing quite well. FXML (and SceneBuilder) are used correctly here.
I would suggest few things:
Use a root container (e.g. StackPane) to host either scene1 or scene2
(better names would be layout1 / layout2). You don't need to use
different Scene here.
Load both fxml files at init time (or lazy loading if needed)
switch from one to the other by removing the content of the root container, and adding the other one.
Now, if the layouts are big, with a lot of css involved, and you need to switch very often from layout1 to layout2, you may want to add both layout in the root container. Then, use:
setVisible()
setManaged()
... on the root of the layout you want to hide / show.
Doing this, you avoid the layout and css steps that is done as soon as you add a node in the scene graph.

Answer 2

While I technically understand, what you want to achieve, I'm still lost about the reason behind it.
If you just want to switch the "main" content of the window, use a StackPane as the root, add multiple Layouts to that stack, and solve your problem by switching the one you want to work on #toFront().
Normally the Layouts on the stack are transparent (except for the controls like buttons and so on, of course), so you would either need to set a background of the stacked Layouts OR (which I would prefer) toggle the visibility of the one in the back (or set opaqueness to 0, or something like that).