为什么我的弹出窗口与我的 ListView 发生冲突？答案

【问题标题】：Why do my popup window collide with my ListView?为什么我的弹出窗口与我的 ListView 发生冲突？
【发布时间】：2016-10-25 19:50:47
【问题描述】：

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

在底部的方法 setListView() 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！

感谢您的帮助！

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.
    }

}

例外：

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

【问题讨论】：

从堆栈跟踪中，当FXMLpopUp1.fxml 文件被加载时，当initialize() 方法调用setListView() 时，您似乎得到了一个空指针异常。但看起来 FXML 文件正在从此控制器加载（在addCustomer() 中）。您是否对两个不同的 FXML 文件使用相同的控制器类？（如果是，为什么？？？）
是的，我使用的是同一个控制器！ FXMLpopUp1.fxml 只是一个带有确认按钮和取消按钮的窗口，但我希望能够根据答案在这个控制器中做不同的事情！我不明白为什么会导致这样的碰撞。我应该补充一点，当我单击按钮并且删除该行时会发生这种情况：customersList.setItems(oList);弹出窗口工作正常！
好吧，您使用的不是同一个控制器，但您的两个控制器（原因只有您知道）来自同一个类。大概你的FXMLpopUp1.fxml 没有fx:id="customersList" 的控件，所以在那个控制器中customersList 是空的，当那个控制器的initialize() 方法调用setListView() 你得到一个空指针异常。即使你使用相同的实际控制器实例，您不会希望在加载第二个 FXML 时重置 customersList。为每个 FXML 文件使用不同的控制器类。
（顺便说一句，“碰撞”这个词并不意味着你认为它的意思：不确定你打算在那里说什么。）
好的，感谢您的快速回答，我将尝试为 FXMLpopUp1.fxml 创建一个新控制器，抱歉我的英语不好！

标签： java listview javafx event-handling

【解决方案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控制器。从堆栈跟踪中可以看出，您已经配置了一些东西，以便两个控制器都来自同一个类。

当FXMLLoader加载FXML文件并创建控制器实例时，它会注入带有fx:id属性匹配的FXML文件中元素注释@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 在该控制器中保持为空。因此，当initialize() 方法调用setListView() 时，您会得到一个空指针异常。

您应该为每个 FXML 文件使用不同的控制器类。 FXMLpopUp1.fxml 的控制器类可能类似于

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”控制器中你可以这样做

@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...
    }
}

【讨论】：