java.lang.reflect.InvocationTargetException从TextField获取值时

本文介绍了java.lang.reflect.InvocationTargetException从TextField获取值时 - Javafx的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是Javafx的新手。我正在通过开发一个简单的应用程序来学习Javafx。我正在尝试从javaFXML中的TextField获取值。我得到了 java.lang.reflect.InvocationTargetException 。

I am new to Javafx. I am learning Javafx by developing a simple application. I am trying go get value from TextField in javaFXML. I got java.lang.reflect.InvocationTargetException.

Javafx文件。

public class Manoj extends Application { @Override public void start(Stage stage) throws Exception { Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml")); Scene scene = new Scene(root); stage.setScene(scene); stage.show(); } /** * @param args the command line arguments */ public static void main(String[] args) { launch(args); } }

FXMLDocument.fxml

FXMLDocument.fxml

<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="480.0" prefWidth="640.0" xmlns="javafx/javafx/8" xmlns:fx="javafx/fxml/1" fx:controller="manoj.FXMLDocumentController"> <children> <AnchorPane layoutX="142.0" layoutY="36.0" prefHeight="361.0" prefWidth="360.0"> <children> <Label fx:id="result" alignment="CENTER" contentDisplay="CENTER" layoutX="61.0" layoutY="289.0" opacity="0.51" prefHeight="77.0" prefWidth="169.0" text="Result Of Addition"> <font> <Font size="18.0" /> </font> </Label> <Label layoutX="26.0" layoutY="108.0" prefHeight="32.0" prefWidth="90.0" text="Number#1 "> <font> <Font size="14.0" /> </font> </Label> <Label alignment="TOP_CENTER" contentDisplay="CENTER" text="First Application" textAlignment="CENTER"> <font> <Font name="Cambria" size="50.0" /> </font> </Label> <Label layoutX="26.0" layoutY="155.0" prefHeight="32.0" prefWidth="90.0" text="Number#2"> <font> <Font size="14.0" /> </font> </Label> <Button fx:id="button" alignment="CENTER" contentDisplay="CENTER" layoutX="83.0" layoutY="216.0" onAction="#addNumber" prefHeight="44.0" prefWidth="125.0" text="Add Number"> <font> <Font name="Cambria" size="14.0" /> </font> </Button> <TextField fx:id="textone" layoutX="141.0" layoutY="108.0" prefHeight="32.0" prefWidth="179.0" /> <TextField fx:id="texttwo" layoutX="141.0" layoutY="155.0" prefHeight="32.0" prefWidth="179.0" /> </children> <padding> <Insets bottom="20.0" left="20.0" right="20.0" /> </padding> </AnchorPane> </children> <padding> <Insets top="20.0" /> </padding> </AnchorPane>

FXMLDocumentController.java

FXMLDocumentController.java

public class FXMLDocumentController implements Initializable { @FXML private Label result; private TextField textone; public FXMLDocumentController() { } @FXML private void addNumber(ActionEvent event) { System.out.println("Clicked. !"); String str = textone.getText(); result.setText(str); } @Override public void initialize(URL url, ResourceBundle rb) { // TODO } }

我正在使用带有场景构建器的netbeans进行开发。当我运行这个项目并单击Add Number按钮时，我得到了一个例外。

I am developing using netbeans with scene builder. When I run this project and click Add Number button, I got an exception.

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1768) at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1651) 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:204) at javafx.scene.Node.fireEvent(Node.java:8175) 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:204) at javafx.scene.Scene$MouseHandler.process(Scene.java:3746) at javafx.scene.Scene$MouseHandler.access$1800(Scene.java:3471) at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1695) at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2486) at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:314) at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:243) at java.security.AccessController.doPrivileged(Native Method) at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:345) at com.sun.glass.ui.View.handleMouseEvent(View.java:526) at com.sun.glass.ui.View.notifyMouse(View.java:898) at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39) at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112) at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:483) at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:483) at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1763) ... 47 more Caused by: java.lang.NullPointerException at manoj.FXMLDocumentController.addNumber(FXMLDocumentController.java:33) ... 57 more

请帮我摆脱这个例外。在此先感谢。

Please help me to get out of this exception. Thanks in advance.

推荐答案

感谢您的评论 Jose Pereda 。

只是一个简单的粗心错误。 Jose Pereda 说，我为 textone ，它工作正常。

Just a simple careless mistake. As Jose Pereda said, I added @FXML annotation for textone and it worked fine.