CODEWITHSUNDEEP
javajavafxfxmlloader
Fabio Cirelli
Fabio Cirelli

Reputation: 65

FXMLLoader.getController() returns null

This section of code executes when the user presses a button, and it should change the scene. The controller of the new scene needs an instance of an object, so I thought of creating a setter method in the new controller class that accepts such object.

Though, when I loader.getController(), this method seems to return null, which causes a NullPointerException to be thrown, as I use try to use that controller's set method. The new controller is instantiated in the new root node in a FXML file.

Here's the code that should load the new scene from the FXML file and do what I said above:

try {
Stage stage = (Stage) anchorPane.getScene().getWindow();
FXMLLoader loader = new FXMLLoader();
Parent newRoot = loader.load(getClass().getResource("ViewRegistrazione.fxml"));
Scene newScene = new Scene(newRoot);
stage.setScene(newScene);
stage.setMinWidth(600);
stage.setMinHeight(400);
stage.setResizable(false);

ViewRegistrazioneController viewRegistrazioneController = loader.getController();
viewRegistrazioneController.setUser(c);
} catch (Exception e) {
        e.printStackTrace();
}

Here's the line in the new FXML file that sets the controller:

<AnchorPane fx:id="anchorPane" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/10.0.2-internal" xmlns:fx="http://javafx.com/fxml/1" fx:controller="EatAdvisor.clienti.ViewRegistrazioneController">

How can I avoid getting a NullPointerException at viewRegistrazioneController.setUser(c); ?

Upvotes: 0

Views: 928

Answers (1)

James_D
James_D

Reputation: 209339

The FXMLLoader.load(URL) method you are calling is a static method. Consequently, it cannot change the state of any FXMLLoader instance (including loader) and so the controller instance in loader remains null.

You need to set the location on the FXMLLoader instance and then call the instance method loader.load() taking no parameters. You can do this either by calling setLocation(...):

FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("ViewRegistrazione.fxml"));
Parent newRoot = loader.load();

or by using the constructor that takes a URL parameter:

FXMLLoader loader = new FXMLLoader(getClass().getResource("ViewRegistrazione.fxml"));
Parent newRoot = loader.load();

Upvotes: 3

Related Questions