Passing data to the controller JAVAFX

问题:

my imageI'm trying to pass the data (variables) from one stage to another stage, but when I try to access them in the second stage they are null. Code of the mainWindow. Go to window1

 public class PrincipalController {
 private Stage primaryStage;
 public void initStage( Stage stage){ primaryStage = stage;}



@FXML
 private void goWindow1(ActionEvent event) {
    try {
         FXMLLoader miCargador = new
                 FXMLLoader(getClass().getResource("/vista/Window1.fxml"));
         Parent root = (Parent) miCargador.load();

                     // Access to window driver 1


 Window1Controller window1 = miCargador.
                  <window1Controlador>getController();
      windnow1.initStage(primaryStage);
      Scene scene = new Scene(root);
      primaryStage.setScene(scene);
      primaryStage.show();
     } catch (IOException e) {e.printStackTrace();}
    }
}

// window1 class:

 public class Window1Controlador {
    private Stage primaryStage;
    private Scene escenaAnterior;
    private String tituloAnterior;
    public void initStage(Stage stage){
         primaryStage = stage;
         escenaAnterior = stage.getScene();
         tituloAnterior = stage.getTitle();
         primaryStage.setTitle("Window 1");
     }

If I want to access previous title that I received comes null

/**
     * Initializes the controller class.
     * @param url
     * @param rb
     */
    @Override
    public void initialize(URL url, ResourceBundle rb) {
       System.out.println(""+ this.tituloAnterior);}

The initialize shows me null when it should show me "Window1" }

回答1:

The initialize() method is called as part of the process of loading the FXML file - in other words it is called when you call miCargador.load().

Obviously this happens before you call window1.initStage(...), so when initialize() is invoked, tituloAnterior is still null.

The simple solution is just not to access tituloAnterior in the initialize() method, but to do whatever you need to do with it in the initStage() method. E.g.

public void initStage(Stage stage){
     primaryStage = stage;
     escenaAnterior = stage.getScene();
     tituloAnterior = stage.getTitle();
     primaryStage.setTitle("Window 1");
     someLabelFromFXML.setText(tituloAnterior);
 }

---

If you prefer, you could set the controller for the FXML loader in the Java code:

@FXML
private void goWindow1(ActionEvent event) {
    try {
         FXMLLoader miCargador = new
                 FXMLLoader(getClass().getResource("/vista/Window1.fxml"));

         Window1Controller window1 = new Window1Controller();
         window1.initStage(primaryStage);
         miCargador.setController(window1);

         Parent root = (Parent) miCargador.load();

                     // Access to window driver 1



      Scene scene = new Scene(root);
      primaryStage.setScene(scene);
      primaryStage.show();
     } catch (IOException e) {e.printStackTrace();}
    }
}

Then remove the fx:controller attribute from your FXML file. This way the initStage() method is called before the load() method, and tituloAnterior will not be null when initialize() is called.