Я не могу установить текст на ярлык

Question

В основном, что я хочу сделать, это отобразить текст на метке при нажатии кнопки, и это дает мне исключение NullPointerException. Я использую JavaFX. Вот сам код (я удалил некоторые из них, потому что я не думаю, что это необходимо):

package controller; 

import java.sql.*; 

import javafx.event.*; 
import javafx.fxml.FXML; 
import javafx.scene.control.*; 

public class LoginController { 
    @FXML private TextField user; 
    @FXML private PasswordField password; 
    @FXML private Button loginButton; 
    @FXML private Button registerButton; 
    @FXML private Label errorLabel1; 

    public void initialize() {} 


    public void login(final WindowManager Manager) { 
    loginButton.setOnAction(new EventHandler<ActionEvent>() { 
     @Override public void handle(ActionEvent event) { 
      user.clear(); 
      password.clear(); 
//The error is in the next line 
      errorLabel1.setText("test"); 
     } 
     }); 
    } 

А вот ошибка я получаю, когда я нажимаю кнопку

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException 
at controller.LoginController$1.handle(LoginController.java:28) 
at controller.LoginController$1.handle(LoginController.java:1) 
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source) 
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source) 
at javafx.event.Event.fireEvent(Unknown Source) 
at javafx.scene.Node.fireEvent(Unknown Source) 
at javafx.scene.control.Button.fire(Unknown Source) 
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(Unknown Source) 
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(Unknown Source) 
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(Unknown Source) 
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(Unknown Source) 
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source) 
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source) 
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source) 
at javafx.event.Event.fireEvent(Unknown Source) 
at javafx.scene.Scene$MouseHandler.process(Unknown Source) 
at javafx.scene.Scene$MouseHandler.access$1500(Unknown Source) 
at javafx.scene.Scene.impl_processMouseEvent(Unknown Source) 
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source) 
at java.security.AccessController.doPrivileged(Native Method) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$350(Unknown Source) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda$175/420645852.get(Unknown Source) 
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(Unknown Source) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source) 
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source) 
at com.sun.glass.ui.View.notifyMouse(Unknown Source) 
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
at com.sun.glass.ui.win.WinApplication.lambda$null$145(Unknown Source) 
at com.sun.glass.ui.win.WinApplication$$Lambda$36/2117255219.run(Unknown Source) 
at java.lang.Thread.run(Unknown Source) 

FXML файл:

<?xml version="1.0" encoding="UTF-8"?> 
<?import javafx.scene.text.*?> 
<?import javafx.scene.control.*?> 
<?import javafx.scene.image.*?> 
<?import java.lang.*?> 
<?import javafx.scene.layout.*?> 
<?import javafx.scene.layout.AnchorPane?> 

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="450.0" prefWidth="330.0" styleClass="background" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="controller.LoginController"> 
    <children> 
     <ImageView fitHeight="128.0" fitWidth="128.0" layoutX="101.0" layoutY="36.0" pickOnBounds="true" preserveRatio="true"> 
     <image> 
      <Image url="@images/safe-icon.png" /> 
     </image> 
     </ImageView> 
     <Label layoutX="24.0" layoutY="175.0" styleClass="label-bright" text="Welcome!"> 
     <font> 
      <Font size="14.0" /> 
     </font> 
     </Label> 
     <Label id="usernameLabel" layoutX="24.0" layoutY="215.0" text="Username:" /> 
     <TextField id="user" fx:id="user" layoutX="165.0" layoutY="213.0" prefHeight="25.0" prefWidth="151.0" /> 
     <Label layoutX="21.0" layoutY="278.0" text="Master password:" /> 
     <Button fx:id="loginButton" layoutX="21.0" layoutY="364.0" mnemonicParsing="false" prefHeight="33.0" prefWidth="111.0" text="Log in." /> 
     <Button fx:id="registerButton" layoutX="144.0" layoutY="364.0" mnemonicParsing="false" prefHeight="33.0" prefWidth="170.0" text="New Registration" /> 
     <PasswordField id="password" fx:id="password" layoutX="165.0" layoutY="276.0" prefHeight="25.0" prefWidth="151.0" /> 
     <Label id="errorLabel1" layoutX="27.0" layoutY="322.0" textFill="RED"> 
     <font> 
      <Font size="14.0" /> 
     </font> 
     </Label> 
    </children> 
</AnchorPane> 

Answer 1

Label не имеет атрибута fx:id. Вам нужно

<Label id="errorLabel1" fx:id="errorLabel1" layoutX="27.0" layoutY="322.0" textFill="RED"> 

(вам не нужно атрибут id дэ, в зависимости от того, или нет, вы используете его для CSS).