java.lang.reflect.InvocationTargetException當從TextField獲取值時 - Javafx

我是Javafx的新手。我通過開發一個簡單的應用程序來學習Javafx。我想從javaFXML中的TextField獲取值。我得到了java.lang.reflect.InvocationTargetException。java.lang.reflect.InvocationTargetException當從TextField獲取值時 - Javafx

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

<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="480.0" prefWidth="640.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/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

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 
    }  

}

我使用NetBeans與現場建設者發展。當我運行這個項目並點擊添加數字按鈕時，我收到了一個異常。

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

請幫我擺脫這個例外。提前致謝。

來源

2014-10-17 Mdumanoj

檢查控制器：'textone'沒有'@ FXML'註釋，所以當你點擊按鈕時，調用'addNumber'，但'textone'是空的，因爲它沒有被實例化。 – 2014-10-17 08:17:30

感謝您的意見Jose Pereda。

只是一個簡單的粗心的錯誤。由於Jose Pereda表示，我爲textone添加了@FXML註釋，它工作正常。

來源

2014-10-18 15:39:34 Mdumanoj

package net.remark.abs.invoice; 

import java.util.Date; 
import javafx.event.ActionEvent; 
import javafx.fxml.FXML; 
import javafx.scene.control.Label; 
import javafx.scene.control.TextField; 
import javafx.scene.layout.AnchorPane; 
import net.remark.abs_bos.Invoice; 
import net.rojer.core.db.DataBase; 
import net.rojer.javafx.tool.Tools; 

public class FrameInvoice extends AnchorPane{ 

    @FXML 
    private TextField fldInvoiceNumber; 

    @FXML 
    private Label lblPrice; 

    public FrameInvoice(){ 
     Tools.innitiateFxml(this); 

    } 

    @FXML 
    private void onSave (ActionEvent event){ 
     Invoice invo = new Invoice(); 
     invo.setDate(new Date()); 
     invo.setTotal(0); 
     invo.setStat((true)); 
     DataBase.begin(); 
     DataBase.em().persist(invo); 
     DataBase.commit(); 
     System.out.println("true"); 
    } 
}

來源

2017-04-08 15:27:41 nelka

您可以通過解釋這些更改來改進此答案，以及如何解決問題 – moondaisy 2017-04-08 16:08:04

我看過很多關於這個錯誤的帖子，其中很多都失敗了。對我來說也是一樣的。嘗試再次製作fxml文件並讓IDE創建控制器和css。保持默認控制器和css名稱的原樣，並將新創建的'.fxml'文件附加到代碼中。對我來說，它可以從場景構建器中複製內容，但不能通過xml代碼。

來源

2017-06-24 11:06:30 Hemantha

java.lang.reflect.InvocationTargetException當從TextField獲取值時 - Javafx

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