JavaFX użycie zmiennej globalnej w metodzie initalize

Question

Witam. Próbuję przekazać Stringa do controllera nowego okna. Wygląda na to, że jest wszystko dobrze poza metodą initalize. Tutaj jak sprawdzam przekazaną wartość wypisuje null.

Jako rozwiązanie widzę stworzyć nową metodę i używać tego parametru np dopiero po kliknięciu na przycisk "start", ale wolałbym, żeby można było go używać już w funkcji initalize.
Poniżej załączam kod i bardzo proszę o pomoc

 

public class MainController implements Initializable {
    public Label lNumberOfQuestion;
    public Label lAmountOfQuestions;
    public Label lNick;
    public Pane pane;
    private String subject;

    public void setlNick(String nick) {
        lNick.setText(nick); // tutaj wyswietla poprawnie
    }

    public void setSubject(String subject) {
        this.subject = subject;
        System.out.println("set:"+this.subject); // tutaj wyswietla poprawnie
    }

    public String getSubject() {
        return subject;
    }
    
    @FXML
    public void buttonA(ActionEvent actionEvent) {
        System.out.println("bb" + subject);//tutaj tez jest dobrze
    }
    
    @FXML
    public void initialize(URL location, ResourceBundle resources) {
        System.out.println("init:"+this.subject); // tutaj jest null
        Pane newPane = null;
        try {
            newPane = FXMLLoader.load(getClass().getResource("../fxmlFile/fourAnswersPane.fxml"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        pane.getChildren().setAll(newPane);
    }


}

Metoda tworząca to nowe okno:

@FXML
public void openMainWindow(String subject) throws IOException {
    FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("../fxmlFile/main.fxml"));//
    Parent root = fxmlLoader.load();//
    Stage stage = new Stage();//
    MainController controller = fxmlLoader.getController();
    controller.setlNick(subject);
    controller.setSubject(subject);
    stage.setScene(new Scene(root));//
    stage.setMaximized(true);//
    stage.show();//
}

Comments

A czym jest subject z metody tworzącej okno, może on jest nie zainicjowany?

A nie sorry gdzie ja mam głowę. Wyjaśnię to w pelnej odpowiedzi

Answer 1

initialize jest wykonywane tutaj:

 Parent root = fxmlLoader.load();//

dlatego ustawienie później subject:

MainController controller = fxmlLoader.getController();
controller.setlNick(subject);
controller.setSubject(subject);

jest, powiedzmy, nieskuteczne. W tym przypadku nie ma ono sensu, ponieważ initialize już się wykonało.

Comments

Teraz już wiem czemu to nie działa, dziękuję :)
Siedzę nad tym od jakiegoś czasu, ale nie potrafię przekazać w żaden sposób tej zmiennej. Jest jakiś sposób na przekazanie parametru do metody initalize?

---

Może przez konstruktor zerknij na ten wątek:

forum.pasja-informatyki.pl/373815/blad-przy-otwieraniu-nowego-okna-javafx

Answer 2

W funkcji otwierającej nowe okno dodałem wiersze opisane *** :

public void openMainWindow(String subject) throws IOException {
        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("../fxmlFile/main.fxml"));//
        MainController controller = new MainController(subject); // ***
        fxmlLoader.setController(controller);//***
        Parent root = fxmlLoader.load();//***
        System.out.println("aaaaaaa");
        Stage stage = new Stage();//
        stage.setScene(new Scene(root));//
        stage.setMaximized(true);//
        stage.show();//
    }

Oraz stworzyłem konstruktor:

public MainController(String subject){
        this.subject = subject;
        System.out.println("z konstruktora: " + subject);
    }

Jednak okno nie otwiera się, a wyswietla się stos wyjątków:

z konstruktora: Informatyka
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
	at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
	at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
	at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
	at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
	at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
	at javafx.event.Event.fireEvent(Event.java:198)
	at javafx.scene.Node.fireEvent(Node.java:8413)
	at com.sun.javafx.scene.control.skin.ComboBoxListViewSkin.handleControlPropertyChanged(ComboBoxListViewSkin.java:179)
	at com.sun.javafx.scene.control.skin.BehaviorSkinBase.lambda$registerChangeListener$61(BehaviorSkinBase.java:197)
	at com.sun.javafx.scene.control.MultiplePropertyChangeListenerHandler$1.changed(MultiplePropertyChangeListenerHandler.java:55)
	at javafx.beans.value.WeakChangeListener.changed(WeakChangeListener.java:89)
	at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
	at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
	at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:105)
	at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112)
	at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
	at javafx.scene.control.ComboBoxBase.setValue(ComboBoxBase.java:150)
	at javafx.scene.control.ComboBox.updateValue(ComboBox.java:463)
	at javafx.scene.control.ComboBox.access$200(ComboBox.java:192)
	at javafx.scene.control.ComboBox$3.changed(ComboBox.java:446)
	at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
	at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
	at javafx.beans.property.ReadOnlyObjectPropertyBase.fireValueChangedEvent(ReadOnlyObjectPropertyBase.java:74)
	at javafx.beans.property.ReadOnlyObjectWrapper.fireValueChangedEvent(ReadOnlyObjectWrapper.java:102)
	at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112)
	at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
	at javafx.scene.control.SelectionModel.setSelectedItem(SelectionModel.java:102)
	at javafx.scene.control.ComboBox$ComboBoxSelectionModel.lambda$new$154(ComboBox.java:494)
	at com.sun.javafx.binding.ExpressionHelper$SingleInvalidation.fireValueChangedEvent(ExpressionHelper.java:137)
	at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
	at javafx.beans.property.ReadOnlyIntegerPropertyBase.fireValueChangedEvent(ReadOnlyIntegerPropertyBase.java:72)
	at javafx.beans.property.ReadOnlyIntegerWrapper.fireValueChangedEvent(ReadOnlyIntegerWrapper.java:102)
	at javafx.beans.property.IntegerPropertyBase.markInvalid(IntegerPropertyBase.java:113)
	at javafx.beans.property.IntegerPropertyBase.set(IntegerPropertyBase.java:147)
	at javafx.scene.control.SelectionModel.setSelectedIndex(SelectionModel.java:68)
	at javafx.scene.control.SingleSelectionModel.updateSelectedIndex(SingleSelectionModel.java:215)
	at javafx.scene.control.SingleSelectionModel.select(SingleSelectionModel.java:149)
	at javafx.scene.control.SingleSelectionModel.selectNext(SingleSelectionModel.java:168)
	at com.sun.javafx.scene.control.behavior.ComboBoxListViewBehavior.selectNext(ComboBoxListViewBehavior.java:87)
	at com.sun.javafx.scene.control.behavior.ComboBoxListViewBehavior.callAction(ComboBoxListViewBehavior.java:68)
	at com.sun.javafx.scene.control.behavior.BehaviorBase.callActionForEvent(BehaviorBase.java:218)
	at com.sun.javafx.scene.control.behavior.ComboBoxBaseBehavior.callActionForEvent(ComboBoxBaseBehavior.java:136)
	at com.sun.javafx.scene.control.behavior.BehaviorBase.lambda$new$74(BehaviorBase.java:135)
	at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
	at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
	at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
	at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
	at javafx.event.Event.fireEvent(Event.java:198)
	at javafx.scene.Scene$KeyHandler.process(Scene.java:3964)
	at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3910)
	at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040)
	at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$352(GlassViewEventHandler.java:248)
	at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
	at com.sun.glass.ui.View.handleKeyEvent(View.java:546)
	at com.sun.glass.ui.View.notifyKey(View.java:966)
	at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
	at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
	at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
	at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
	... 80 more
Caused by: javafx.fxml.LoadException: Controller value already specified.
/E:/Projekty/Quiz/out/production/Quiz/fxmlFile/main.fxml:8

	at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2597)
	at javafx.fxml.FXMLLoader.access$100(FXMLLoader.java:103)
	at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:914)
	at javafx.fxml.FXMLLoader$InstanceDeclarationElement.processAttribute(FXMLLoader.java:971)
	at javafx.fxml.FXMLLoader$Element.processStartElement(FXMLLoader.java:220)
	at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:744)
	at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
	at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
	at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
	at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
	at controllers.SelectionController.openMainWindow(SelectionController.java:51)
	at controllers.SelectionController.clickWyslij(SelectionController.java:90)
	at controllers.SelectionController.clickCbSelectQuestions(SelectionController.java:94)
	... 90 more

Po wyszukaniu jednego z nich znalazłem informację, że powinieniem usunąć fx:controller z pliku fxml. Jednak nie do końca wiem jak inaczej wtedy uzyskać dostęp do Controllera dla tego pliku fxml

Comments

Kontroler przypisujesz tutaj:

fxmlLoader.setController(controller)

więc linia w fxml jest zbędna.

---

Kurcze, w pliku fxml świeciło mi się na czerwono i to mnie zmyliło.
Dziękuję bardzo za pomoc :)