How to swap screens in a JavaFX application in the controller class?

Question

If there are 3 files in a JavaFX project; an FXML file, a controller for the FXML, and an application class; how can the controller respond to a button click (which works perfectly fine) with changing the screen on that click (which is normally done with stage.setScreen())? I have no reference to the stage (which is passed to the application class's start(Stage)).

Application sample:

public class JavaFXApplication4 extends Application {      @Override     public void start(Stage stage) throws Exception {         Parent root = FXMLLoader.load(getClass().getResource("Sample.fxml"));          Scene scene = new Scene(root);          stage.setScene(scene);         stage.show();     }      /**      * The main() method is ignored in correctly deployed JavaFX application.      * main() serves only as fallback in case the application can not be      * launched through deployment artifacts, e.g., in IDEs with limited FX      * support. NetBeans ignores main().      *      * @param args the command line arguments      */     public static void main(String[] args) {         launch(args);     } } 

FXML sample:

<?xml version="1.0" encoding="UTF-8"?>  <?import java.lang.*?> <?import java.util.*?> <?import javafx.scene.*?> <?import javafx.scene.control.*?> <?import javafx.scene.layout.*?>  <AnchorPane id="AnchorPane" prefHeight="200.0" prefWidth="320.0"  xmlns:fx="http://javafx.com/fxml" fx:controller="javafxapplication4.SampleController">   <children>   <Button id="button" fx:id="nextScreen" layoutX="126.0" layoutY="90.0" onAction="#handleButtonAction" text="Next Screen" />   <Label fx:id="label" layoutX="126.0" layoutY="120.0" minHeight="16.0" minWidth="69.0" />   </children> </AnchorPane> 

Controller sample:

public class SampleController implements Initializable {      @FXML     private Label label;      @FXML     private void handleButtonAction(ActionEvent event) {         System.out.println("You clicked me!");         label.setText("Hello World!");          // Here I want to swap the screen!     }      @Override     public void initialize(URL url, ResourceBundle rb) {         // ...     }     } 

Answer 1

@FXML private void handleButtonAction(ActionEvent event) {     System.out.println("You clicked me!");     label.setText("Hello World!");     //Here I want to swap the screen!      Stage stageTheEventSourceNodeBelongs = (Stage) ((Node)event.getSource()).getScene().getWindow();     // OR     Stage stageTheLabelBelongs = (Stage) label.getScene().getWindow();     // these two of them return the same stage     // Swap screen     stage.setScene(new Scene(new Pane())); }