How to stay in the same fxml when calling an Alert Class? - javafx

Question

I have created this methode for Email validation
The issue is that the Alert displayed goes on the top of the previous fxml instead of the same and the user have to fulfill all the fields again
I have this method
public boolean validateEmail() {
Pattern p = Pattern.compile("[a-zA-Z0-9][a-zA-Z0-9._]*#[a-zA-Z0-9]+([.][a-zA-Z]+)+");
Matcher m = p.matcher(emailField.getText());
if (m.find() && m.group().equals(emailField.getText())) {
return true;
} else {
Alert alert = new Alert(Alert.AlertType.WARNING);
alert.setTitle("Validation of Email");
alert.setHeaderText(null);
alert.setContentText("Please enter a valid Email");
alert.showAndWait();
return false;
}
}
I have a button which onAction calls the method below
public void showSubscription() throws IOException {
Dialog<ButtonType> dialog = new Dialog<>();
dialog.setTitle("New Subscription");
dialog.setHeaderText("Please Fulfill your information to subscribe");
FXMLLoader fxmlLoader = new FXMLLoader();
fxmlLoader.setLocation(getClass().getResource("Registration.fxml"));
try {
dialog.getDialogPane().setContent(fxmlLoader.load());
} catch (IOException e) {
System.out.println("Couldn't load the Dialog");
e.printStackTrace();
return;
}
dialog.getDialogPane().getButtonTypes().add(ButtonType.OK);
dialog.getDialogPane().getButtonTypes().add(ButtonType.CANCEL);
Optional<ButtonType> result = dialog.showAndWait();
if (result.isPresent() && result.get()==ButtonType.OK) {
RegistrationController controller = fxmlLoader.getController();
if (controller.validateEmail()) {
controller.loadRegistration();
Alert alert = new Alert(Alert.AlertType.INFORMATION);
alert.setTitle("Information");
alert.setHeaderText(null);
alert.setContentText("Subscription Done Correctly");
alert.showAndWait();
}
}
else {
System.out.println("CANCEL pressed");
}
}
I don't know what to add to make this Alert popup in the same Registration.fxml and not go back to the previous one.

Answer 1

Alert inherits an initOwner(Window) method from Dialog. So you can call initOwner(...) and pass in the window responsible for showing the dialog. There's no direct reference to this, but you can get it from the scene containing the dialog's dialog pane:
alert.initOwner(dialog.getDialogPane().getScene().getWindow());
This line just needs to be called sometime before alert.showAndWait().
If you need the Alert created in the validateEmail() method to have the same owner, just pass a reference to the appropriate window to that method:
public boolean validateEmail(Window mainWindow) {
// ...
Alert alert = new Alert(Alert.AlertType.WARNING);
alert.initOwner(mainWindow);
// ...
alert.showAndWait();
// ...
}
and
RegistrationController controller = fxmlLoader.getController();
if (controller.validateEmail(dialog.getDialogPane().getScene().getWindow())) {
// ...
}