Tabs NPE Tab.getSelectionModel（）JavaFx

我有一个问题： 我得到了一个选项卡窗格，设计在一个FXML文件中。现在我想在单击“检查”按钮时更改所选选项卡的名称

public void onAddDateRequest(){ 
    try {
        //datePane wird in den FXML Loader geladen
        FXMLLoader loader = new FXMLLoader(getClass().getResource("/homenizer/view/datePane.fxml"));
        Parent content = (Parent)loader.load();
        Tab tab = new Tab("Neuer Termin");
        tab.setContent(content); //Dem neuen Tab wird das Layout der FXXML Datei aus Content zugewiesen
        tabPane.getTabs().add(tab);
    } catch (IOException ex) {
        Logger.getLogger(HomenizerController.class.getName()).log(Level.SEVERE, null, ex);
    }
  }

  public void onCheckRequest(){
    Date date = new Date();
    tabPane.getSelectionModel().getSelectedItem().setText("A");

  }

单击按钮添加新选项卡时，将调用“onAddDateRequest”方法

这里是FXML文件：

<TabPane fx:id="tabPane">
        <Tab text="Willkommen" closable="true" > 
            <VBox>
                <TitledPane text="Allgemeines" expanded="true">
                    <GridPane>
                        <Label text="Benutzername:" GridPane.columnIndex="0" GridPane.rowIndex="0" />
                        <Label fx:id="username" GridPane.columnIndex="1" GridPane.rowIndex="0" />
                        <Label text="Termine gesamt:" GridPane.columnIndex="0" GridPane.rowIndex="1" />
                        <Label fx:id="dates" GridPane.columnIndex="1" GridPane.rowIndex="1" /> 
                        <Label text="Aufgaben gesamt:" GridPane.columnIndex="0" GridPane.rowIndex="2" /> 
                        <Label fx:id="toDos" GridPane.columnIndex="1" GridPane.rowIndex="2" />
                    </GridPane>
                </TitledPane>
                <TitledPane text="Aktuell" expanded="true" >
                    <ScrollPane>
                        <GridPane>
                            <Label text="Aktuelle Termine:" GridPane.columnIndex="0" GridPane.rowIndex="0" />
                            <Label fx:id="actualDates" GridPane.columnIndex="1" GridPane.rowIndex="0" />
                            <Label text="Aktuelle Aufgaben:" GridPane.columnIndex="0" GridPane.rowIndex="1" />
                            <Label fx:id="actualToDos" GridPane.columnIndex="1" GridPane.rowIndex="1" /> 
                        </GridPane> 
                    </ScrollPane>
                </TitledPane>
            </VBox>
        </Tab>
       </TabPane>

---

谢谢你的帮助，我不知道你是否需要更多我的代码，但是我确信他们在我的代码中没有错误

因此我发现了错误：）我在controllercode中为我的FXML设置了控制器，而不是在FXML文件本身中，现在它可以工作了

发布其余代码。如果tabPane不为null，是否在调试模式下选中？tabPane是您在FXML上指示的fx:id吗？很难知道该代码的问题好吧，我已经编辑了我的邮戳，因为您的选项卡窗格不为空，但可能存在这样一种情况，即您没有选择任何内容，并且getSelectedItem（）必须返回nullHmm…当我调用getSelectedIndex（）方法时，它始终返回-1。如果调用getTabs（）.getSize（）方法，它总是返回0。另外，我想知道为什么我必须在我的控制器中初始化我的TabPane，如果我不初始化它，我还通过上面提到的两种方法得到了一个NPE。

<ScrollPane fx:id="scrollPane" minHeight="350.0" xmlns:fx="http://javafx.com/fxml" fx:controller="homenizer.controller.HomenizerController"> 
<VBox>
    <TitledPane text="Termin" expanded="true"> 
        <GridPane fx:id="datePane" alignment="TOP_LEFT" hgap="10" vgap="10" prefWidth="900" >
            <Label text="Termin Beschreibung" GridPane.columnIndex="0" GridPane.rowIndex="1" />
            <TextField fx:id="dateInformation" GridPane.columnIndex="1" GridPane.rowIndex="1" />
            <Label text="Datum" GridPane.columnIndex="0" GridPane.rowIndex="2" />
            <TextField fx:id="dateOfDate" GridPane.columnIndex="1" GridPane.rowIndex="2" />
            <Label text="Termin beginn" GridPane.columnIndex="0" GridPane.rowIndex="3" />
            <TextField fx:id="dateTimeBegin" GridPane.columnIndex="1" GridPane.rowIndex="3" />
            <Label text="Termin ende" GridPane.columnIndex="2" GridPane.rowIndex="3" />
            <TextField fx:id="dateTimeEnd" GridPane.columnIndex="3" GridPane.rowIndex="3" /> 
            <Label text="Priorität" GridPane.columnIndex="0" GridPane.rowIndex="4" />
            <fx:define>
                <ToggleGroup fx:id="priorityGroup" />
            </fx:define>
            <RadioButton text="Hoch" GridPane.columnIndex="1" GridPane.rowIndex="4" toggleGroup="$priorityGroup" />
            <RadioButton text="Normal" GridPane.columnIndex="1" GridPane.rowIndex="5" toggleGroup="$priorityGroup"/>
            <RadioButton text="Niedrig" GridPane.columnIndex="1" GridPane.rowIndex="6" toggleGroup="$priorityGroup"/>
        </GridPane>    
    </TitledPane>
    <TitledPane text="Person/Unternehmen" ellipsisString="Persson / Unternehmen"  expanded="false" >
        <GridPane fx:id="personCompanyPane" hgap="10" vgap="10">
            <Label text="Name" GridPane.columnIndex="0" GridPane.rowIndex="0" />
            <TextField fx:id="name" GridPane.columnIndex="1" GridPane.rowIndex="0" /> 
            <Label text="Vorname" GridPane.columnIndex="0" GridPane.rowIndex="1" />
            <TextField fx:id="firstname" GridPane.columnIndex="1" GridPane.rowIndex="1" />
            <Label text="Ort" GridPane.columnIndex="0" GridPane.rowIndex="2" />
            <TextField fx:id="city" GridPane.columnIndex="1" GridPane.rowIndex="2" />
            <Label text="PLZ" GridPane.columnIndex="2" GridPane.rowIndex="2" />
            <TextField fx:id="place" maxWidth="60"  GridPane.columnIndex="3" GridPane.rowIndex="2" />    
            <Label text="Strasse" GridPane.columnIndex="0" GridPane.rowIndex="3" />
            <TextField fx:id="street" GridPane.columnIndex="1" GridPane.rowIndex="3" />
            <Label text="Hausnr." GridPane.columnIndex="2" GridPane.rowIndex="3" />
            <TextField fx:id="houseNr" maxWidth="35" GridPane.columnIndex="3" GridPane.rowIndex="3"  />
            <Label text="Unternehmen" GridPane.columnIndex="0" GridPane.rowIndex="4" />
            <TextField fx:id="company" GridPane.columnIndex="1" GridPane.rowIndex="4" />
        </GridPane>
    </TitledPane>  
    <TitledPane text="Notiz" expanded="false" >
        <GridPane>
            <Label text="Notiz" GridPane.columnIndex="0" GridPane.rowIndex="0" />
            <TextArea GridPane.columnIndex="0" GridPane.rowIndex="1" prefWidth="900"  />    
        </GridPane>
    </TitledPane> 
    <HBox>
        <Button fx:id="check" text="bestätigen" 
            onAction="#onCheckRequest"/>
        <Button fx:id="cancel" text="abbrechen" />
    </HBox>
</VBox> 

    java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1456)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.Node.fireEvent(Node.java:6867)
    at javafx.scene.control.Button.fire(Button.java:179)
    at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:193)
    at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:336)
    at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:329)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:64)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
    at javafx.event.Event.fireEvent(Event.java:171)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3369)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3209)
    at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3164)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1582)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2267)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:250)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:173)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:292)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:530)
    at com.sun.glass.ui.View.notifyMouse(View.java:924)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:17)
    at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:67)
    at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:75)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:279)
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1453)
    ... 64 more
Caused by: java.lang.NullPointerException
    at homenizer.controller.HomenizerController.onCheckRequest(HomenizerController.java:105)
    ... 74 more