java - 为什么我的弹出窗口与 ListView 发生冲突？

Question

嘿，这是我正在为学校编写的程序的一部分，出于某种原因，我的弹出窗口“event addCustomer”与以下行发生冲突: customerList.setItems(oList);

在底部的setListView()方法中？ 有任何想法吗？ 如果您需要程序的其余部分，我可以根据要求发布!

感谢帮助!

public class FXMLDocumentController implements Initializable {

    private BankLogic b;

    private ObservableList<String> oList;

    @FXML
    private ListView customersList;

    @FXML
    private Button addCustomerButton, deleteCustomerButton;

    @FXML
    private Button confirmPop1, cancelPop1, confirmPop2, cancelPop2;


    @FXML
    private void addCustomer(ActionEvent event) throws IOException {

        Stage stage;
        Parent root;

        stage = new Stage();
        root = FXMLLoader.load(getClass().getResource("FXMLpopUp1.fxml"));
        stage.setScene(new Scene(root));
        stage.initModality(Modality.APPLICATION_MODAL);
        stage.initOwner(addCustomerButton.getScene().getWindow());
        stage.showAndWait();
    } // opens a confirm window with 2 buttons:

    @FXML
    private void confirmPop1(ActionEvent event) {

        Stage stg = (Stage) ((Node) event.getSource()).getScene().getWindow();
        stg.close();

    }

    @FXML
    private void cancelPop1(ActionEvent event) {

        Stage stg = (Stage) ((Node) event.getSource()).getScene().getWindow();
        stg.close();

    }

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        b = BankLogic.getInstance();


        long nr = 198905643943L;
        b.addCustomer("Kalle karlsson", nr); 
        nr = 198905643843L;
        b.addCustomer("Peter haraldsson", nr);
        nr = 198967643943L;
        b.addCustomer("Hans haraldsson", nr);
        nr = 198905643978L;
        b.addCustomer("Harry haraldsson", nr);
       // 4 objects of a class called Customer!

        setListView(); // calling method to fill ListView 

    }

    public void setListView() {  
        oList = FXCollections.observableArrayList();

        ArrayList<Customer> tC = b.getCustomerList();
        for (Customer c : tC) {
            String s = c.getName() + " " + c.getPnr();
            oList.add(s);
        }

        customersList.setItems(oList); // This line collides with my popup window and givs me an exception.
    }

}

异常(exception):

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:8411)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:352)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:388)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:387)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)

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:497)
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:497)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
... 45 more
Caused by: javafx.fxml.LoadException: file:/NetBeansProjects/Grupp1-Bank/dist/run1287972729/BankSystem.jar!/banksystem/FXMLpopUp1.fxml

at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at banksystem.FXMLDocumentController.addCustomer(FXMLDocumentController.java:86)
... 55 more
Caused by: java.lang.NullPointerException
at banksystem.FXMLDocumentController.setListView(FXMLDocumentController.java:193)
at banksystem.FXMLDocumentController.initialize(FXMLDocumentController.java:180)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
... 63 more

Answer 1

您正在加载两个不同的 FXML 文件，因此会为您创建两个不同的 Controller 。从堆栈跟踪看来，您已经配置了一些东西，以便两个 Controller 都来自同一个类。

当 FXMLLoader 加载 FXML 文件并创建 Controller 实例时，它会使用 FXML 文件中具有匹配 fx:id 属性的元素注入(inject)注释为 @FXML 的字段，然后调用 initialize() 方法。

您的 FXMLpopUp1.fxml 似乎没有任何带有 fx:id="customersList" 的元素，因此 customersList 在该 Controller 中保持为 null。因此，当 initialize() 方法调用 setListView() 时，您会遇到空指针异常。

您应该为每个 FXML 文件使用不同的 Controller 类。 FXMLpopUp1.fxml 的 Controller 类可能类似于

public class PopupController {

    @FXML
    private Button confirmPop ;

    private boolean confirmed = false ;

    public void isConfirmed() {
        return confirmed ;
    }

    @FXML
    private void confirmPop() {
        confirmed = true ;
        confirmPop.getScene().getWindow().hide();
    }

    @FXML
    private void cancelPop() {
        confirmed = false ;
        confirmPop.getScene().getWindow().hide();
    }
}

然后在你的“主” Controller 中你可以这样做

@FXML
private void addCustomer(ActionEvent event) throws IOException {

    Stage stage;
    Parent root;

    stage = new Stage();
    FXMLLoader loader = new FXMLLoader(getClass().getResource("FXMLpopUp1.fxml"));
    root = loader.load();
    PopupController popupController = loader.getController();
    stage.setScene(new Scene(root));
    stage.initModality(Modality.APPLICATION_MODAL);
    stage.initOwner(addCustomerButton.getScene().getWindow());
    stage.showAndWait();
    if (popupController.isConfirmed()) {
        // confirm button was pressed...
    }
}