How to get reference to another controller - JavaFX - javafx

Question

Let's say I've got 3 views and 3 controllers:
LogInController, LogInView
MainMenuController, MainMenuView
ListOfPatientsInternalMedicineController, ListOfPatientsInternalMedicineView.
An internalMedicineButtonClicked method change my scene to another (with some other content) but in this new scene, I want to have a button which allows me to go back to MainMenu (goBacktoMainMenuButtonClicked() method). And here occures my problem. How am I able to get reference to MainMenuController (the one which is corresponding with fxml file, created in LogInController) to fill setController() method.
public class LogInController {
MainMenuController mainMenuController = new MainMenuController();
#FXML
private JFXTextField logInTextField;
#FXML
private JFXButton logInButton;
#FXML
private JFXPasswordField passwordTextField;
#FXML
void logInButtonClicked(ActionEvent event) throws IOException {
LogInDAO logInDAO = new LogInDAO();
if(logInDAO.checkIfLoginAndPasswordIsCorrect(logInTextField.getText(),passwordTextField.getText()))
{
FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/MainMenu.fxml"));
Window window = logInButton.getScene().getWindow();
Stage stage = (Stage) window;
loader.setController(mainMenuController); // here i'm passing original controller corresponding with fmxl
stage.setScene(new Scene(loader.load()));
}
else
{
(...)
}
}
}
MainMenuCotroller class:
public class MainMenuController {
ContentOfPatientTableView patientTableViewModel = new ContentOfPatientTableView();
(..)
#FXML
void internalMedicineButtonClicked(ActionEvent event) throws IOException {
FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/ListOfPatientsInternalMedicineView.fxml"));
Button button = (Button) event.getSource();
Scene scene = button.getScene();
Stage stage = (Stage) scene.getWindow();
loader.setController(new ListOfPatientsInternalMedicineController(patientTableViewModel));
stage.setScene(new Scene(loader.load()));
}
And ListOfPatientsInternalMedicineController class;
public class ListOfPatientsInternalMedicineController {
IPatientDAO patientDAO = new PatientDAO();
ContentOfPatientTableView patientTableViewModel;
public ListOfPatientsInternalMedicineController(ContentOfPatientTableView content) {
patientTableViewModel=content;
}
#FXML
public void goBacktoMainMenuButtonClicked(ActionEvent event)
{
FXMLLoader loader = new FXMLLoader(MainMenuController.class.getResource("/fxml/MainMenuView.fxml");
loader.setController(?????????); // Here if I will pass new MainController() i will create new instance, not this which is corresponding with fxml file. How am I able to refer to instance MainController created in LogInController ?
}
}

Answer 1

Consider using another model to represent the current view. You could implement this along the following lines:
public class ViewState {
private final ContentOfPatientTableView patientTableViewModel ;
private final ReadOnlyObjectWrapper<Parent> currentView = new ReadOnlyObjectWrapper<>();
private Parent logInView ;
private Parent mainMenuView ;
private Parent listOfPatientsMainMedicineView ;
public ViewState(ContentOfPatientTableView patientTableViewModel) {
this.patientTableViewModel = patientTableViewModel ;
}
public ReadOnlyObjectProperty<Parent> currentViewProperty() {
return currentView.getReadOnlyProperty();
}
public void showLogIn() {
if (logInView == null) {
try {
FXMLLoader loader = new FXMLLoader("/fxml/LogIn.fxml");
loader.setController(new LogInController(this));
logInView = loader.load();
} catch (IOException exc) {
// fatal...
throw new UncheckedIOException(exc);
}
}
currentView.set(logInView);
}
public void showMainMenu() {
// similarly...
}
public void showListOfPatientsMainMedicineView() {
// ...
}
}
Now your LogInController can do:
public class LogInController {
private final ViewState viewState ;
#FXML
private JFXTextField logInTextField;
#FXML
private JFXButton logInButton;
#FXML
private JFXPasswordField passwordTextField;
public LogInController(ViewState viewState) {
this.viewState = viewState ;
}
#FXML
void logInButtonClicked(ActionEvent event) {
LogInDAO logInDAO = new LogInDAO();
if(logInDAO.checkIfLoginAndPasswordIsCorrect(logInTextField.getText(),passwordTextField.getText()))
{
viewState.showMainMenu();
}
else
{
(...)
}
}
}
Similarly,
public class MainMenuController {
private final ViewState viewState ;
public MainMenuController(ViewState viewState) {
this.viewState = viewState ;
}
#FXML
void internalMedicineButtonClicked(ActionEvent event) throws IOException {
viewState.showListOfPatientsMainMedicineView();
}
}
and similarly for the other controller.
Note that you are instantiating each controller in ViewState, so just give that class access to each of the other models it may need.
Finally, you boot all this up with
public class MyApp extends Application {
#Override
public void start(Stage primaryStage) {
ViewState viewState = new ViewState(/* pass models here...*/);
viewState.showLogIn();
Scene scene = new Scene(viewState.currentViewProperty().get());
scene.rootProperty().bind(viewState.currentViewProperty());
primaryStage.setScene(scene);
primaryStage.show();
}
}