Subcontroller loses passed data from MainController

Question

I have searched this problem for days now and can't find a solution. I have a MainController which is supposed to hold an ArrayList. When I start the Application the SubController is supposed to be initialised in the initialize() method of the MainController. It does work, but if i try to refer on the ArrayList from the MainController from another method in the SubController I always get a NullPointerExeption and I have no idea why. Here is my Code.

Controller.java:

public class Controller {

    public ArrayList<Film> filme = new ArrayList<Film>();

    @FXML Controller1 controller1 = new Controller1();

    ...

    @FXML
    public void initialize() {
        ...
        controller1.init(this);
        ...
    }

    ...
}

Rahmen.fxml:

<?xml version="1.0" encoding="UTF-8"?>

<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>


<AnchorPane xmlns:fx="http://javafx.com/fxml/1" 
xmlns="http://javafx.com/javafx/8" fx:controller="GUI.Controller" 
fx:id="test">
    <!-- TODO Add Nodes -->
    <fx:include fx:id="tab1" source="StartBildschirm.fxml" />
</AnchorPane>

Controller1.java:

public class Controller1 {

    private Controller main;

    @FXML private Pane film1;

    public void init(Controller controller) {
        main = controller;
        System.out.println(main.filme.get(0).getTitel());
    }

    @FXML
    public void test(MouseEvent e) {

        System.out.println(main.filme.get(0).getTitel());
    }

    ...
}

StartBildschirm.fxml:

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.text.*?>
<?import javafx.geometry.*?>
<?import javafx.scene.image.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane prefWidth="1040.0" xmlns="http://javafx.com/javafx/8" 
xmlns:fx="http://javafx.com/fxml/1" fx:controller="GUI.Controller1">

...

</AnchorPane>

The first Syso works just fine and gives me the correct value, but as I said, the second one always has a NullPointerExeption. Does anyone has an idea on how to getting it fixed?

https://stackoverflow.com/questions/50653235/show-tableview-data-into-another-window-contains-textfield-in-javafx/50653518#50653518 — SedJ601, Aug 11 '18 at 19:21
https://stackoverflow.com/questions/50774910/gethostservices-showdocument-in-a-fxml-file/50775157#50775157 — SedJ601, Aug 11 '18 at 19:21
Possible duplicate of [Passing Parameters JavaFX FXML](https://stackoverflow.com/questions/14187963/passing-parameters-javafx-fxml) — SedJ601, Aug 11 '18 at 19:22

score 1 · Accepted Answer · answered Aug 12 '18 at 03:22

You're creating a new instance of the Controller1 class that is not used with any fxml instead of using the instance used with the included fxml. To inject the controller of a included fxml to a field of the controller for the fxml containing the <fx:include> the name of the field needs to be the fx:id of the <fx:include> element concatenated with "Controller" i.e. in your case

@FXML
private Controller1 tab1Controller;

score 0 · Answer 2 · answered Aug 11 '18 at 19:18

0

JavaFX will create an instance of the controller class on its own, if you want to use an instance you created in your code, you need to pass this instance to the respective FXMLLoader via its setController method.

answered Aug 11 '18 at 19:18

Lukas Körfer

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Subcontroller loses passed data from MainController

2 Answers2