Change the scene (load another FXML file) - javafx

Question

I launch my application using this Main.java file:
package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Parent;
import javafx.scene.Scene;
public class Main extends Application {
Parent root;
#Override
public void start(Stage stage) throws Exception {
root = FXMLLoader.load(getClass().getResource("../fxml/mainpage.fxml"));
Scene scene = new Scene(root);
stage.setTitle("Smart City - Main Page");
stage.setScene(scene);
stage.setMaximized(true);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
I also created a class named ScreenChanger.java:
package utils;
import java.io.IOException;
import javafx.event.Event;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class ScreenChanger {
public static void screenChanger(Event event, String path, String title) throws IOException{
Parent root = FXMLLoader.load(getClass().getResource(path));
Scene scene = new Scene(root);
Stage stage = (Stage) ((Node) event.getSource()).getScene().getWindow();
stage.setScene(scene);
stage.setTitle(title);
stage.setMaximized(false);
stage.setMaximized(true);
stage.show();
}
}
The problem is that sometimes I haven't that Event in my code when I want to switch between scenes. I would like to use something else instead of Stage stage = (Stage) ((Node) event.getSource()).getScene().getWindow(); in order to change the screen.