コンポーネントをコンポーネントにロードするときのJavaFX NullPointerException

-1

BorderPaneの中心にいくつかのHBoxを追加しようとしています。ボタンを押すとNullPointerExceptionが表示されます。なぜ私はそれが働いてチュートリアルアプリではわからない。コンポーネントをコンポーネントにロードするときのJavaFX NullPointerException

はcontrollers.MainController.setCenter でcontrollers.TopMenuButtonsController.todoOnAction

public class Main extends Application { 
    public static void main(String[] args) { 
     launch(args); 
    } 
    public void start(Stage primaryStage) throws Exception { 
     FXMLLoader fxmlLoader = new FXMLLoader(this.getClass().getResource("/fxml/BorderPaneMainFXML.fxml")); 
     BorderPane borderPane = fxmlLoader.load(); 
     Scene scene = new Scene(borderPane); 
     primaryStage.setScene(scene); 
     primaryStage.setTitle("TITLE"); 
     primaryStage.show(); 
    } 
} 



public class TopMenuButtonsController { 
    @FXML 
    private MainController mainController; 

    public void setMainController(MainController mainController) { 
     this.mainController = mainController; 
    } 

    @FXML 
    public void todoOnAction() { 
     mainController.setCenter("/fxml/TodoFXML.fxml"); 

    } 
} 



public class MainController { 
    @FXML 
    public BorderPane borderPane; 
    @FXML 
    public TopMenuButtonsController topMenuButtonsController; 
    @FXML 
    public void initialize(){ 
     topMenuButtonsController.setMainController(this); 
    } 

    public void setCenter(String fxmlPatch) { 
     FXMLLoader fxmlLoader = new FXMLLoader(this.getClass().getResource(fxmlPatch)); 
     Parent parent = null; 
     try { 
      parent = fxmlLoader.load(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     borderPane.setCenter(parent); 
    } 
} 



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

<?import javafx.scene.layout.BorderPane?> 


<?import javafx.scene.layout.VBox?> 
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="800.0" prefWidth="640.0" style="-fx-background-color: #2C3E50;" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="controllers.MainController" > 
    <top> 
     <VBox> 
      <fx:include fx:id="topMenuButtons" source="TopMenuButtons.fxml"/> 
     </VBox> 
    </top> 


</BorderPane> 


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

<?import com.jfoenix.controls.JFXButton?> 
<?import javafx.scene.layout.HBox?> 
<?import javafx.scene.text.Font?> 

<HBox maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="controllers.TopMenuButtonsController"> 
    <children> 
     <JFXButton onAction="#todoOnAction" ripplerFill="#3498db" text="todo" textFill="#ecf0f1"> 
     <font> 
      <Font name="MS Outlook" size="14.0" /> 
     </font></JFXButton> 
     <JFXButton onAction="#gridOnAction" ripplerFill="#3497d9" text="grid" textFill="#ecf0f1"> 
     <font> 
      <Font name="MS Outlook" size="14.0" /> 
     </font></JFXButton> 
     <JFXButton onAction="#statsOnAction" ripplerFill="#3497d9" text="statistics" textFill="#ecf0f1"> 
     <font> 
      <Font name="MS Outlook" size="14.0" /> 
     </font></JFXButton> 
     <JFXButton onAction="#notesOnAction" ripplerFill="#3497d9" text="notes" textFill="#ecf0f1"> 
     <font> 
      <Font name="MS Outlook" size="14.0" /> 
     </font></JFXButton> 
     <JFXButton onAction="#prefOnActionn" ripplerFill="#3497d9" text="preferences" textFill="#ecf0f1"> 
     <font> 
      <Font name="MS Outlook" size="14.0" /> 
     </font></JFXButton> 
     <JFXButton onAction="#settingsOnAction" ripplerFill="#3497d9" text="settings" textFill="#ecf0f1"> 
     <font> 
      <Font size="14.0" /> 
     </font></JFXButton> 
    </children> 
</HBox> 


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

<?import javafx.scene.control.Label?> 
<?import javafx.scene.layout.HBox?> 


<HBox maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1"> 
    <children> 
     <Label prefHeight="136.0" prefWidth="221.0" text="Lasdfasdfsdafsdfsdbel" /> 
    </children> 
</HBox>

<!-- language: lang-none --> 

    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 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$MouseEventNotification.run(GlassViewEventHandler.java:381) 
     at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295) 
     at java.security.AccessController.doPrivileged(Native Method) 
     at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417) 
     at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389) 
     at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416) 
     at com.sun.glass.ui.View.handleMouseEvent(View.java:555) 
     at com.sun.glass.ui.View.notifyMouse(View.java:937) 
     at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
     at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191) 
     at java.lang.Thread.run(Thread.java:745) 
    Caused by: java.lang.reflect.InvocationTargetException 
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
     at java.lang.reflect.Method.invoke(Method.java:498) 
     at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
     at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
     at java.lang.reflect.Method.invoke(Method.java:498) 
     at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
     at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771) 
     ... 48 more 
    Caused by: java.lang.NullPointerException 
     at controllers.MainController.setCenter(MainController.java:34) 
     at controllers.TopMenuButtonsController.todoOnAction(TopMenuButtonsController.java:40) 
     ... 58 more

出典

2017-05-26 m.s

の質問では、完全なスタックトレースを必要とします。どの実際の行が例外をスローしていますか？ –

これは34行目ですか？ –

borderPane.setCenter（親）; --- 34 mainController.setCenter（ "/ fxml/TodoFXML.fxml"）; --- 40 –

であなたの<BorderPane>タグがfx:id属性が欠落しているので、それをコントローラに注入取得されていません。したがって、borderPaneはコントローラではnullであり、borderPane.setCenter(...)を呼び出すとnullポインタ例外が発生します。

あなたが

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

<?import javafx.scene.layout.BorderPane?> 


<?import javafx.scene.layout.VBox?> 
<BorderPane fx:id="borderPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="800.0" prefWidth="640.0" style="-fx-background-color: #2C3E50;" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="controllers.MainController" > 
    <top> 
     <VBox> 
      <fx:include fx:id="topMenuButtons" source="TopMenuButtons.fxml"/> 
     </VBox> 
    </top> 


</BorderPane>

出典

2017-05-26 17:57:50

コンポーネントをコンポーネントにロードするときのJavaFX NullPointerException

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