我想在另一个fxml中更改标签中的文本。

Question

我想根据发生事件的GridPane的行和列来更改另一个fxml中标签中的文本。我发现了类似的错误和方法，但无法应用代码。我知道Label食物为空。但是我不知道如何实例化食物（标签）。我在另一个fxml中的Label中声明了Label，并尝试执行“ food.setText（“ ~~”）“，但是发生错误。如何在另一个fxml文件中实例化Label？

Main.java：

package application;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {
    @Override
    public void start(Stage primaryStage) {
        try {
            Parent root=FXMLLoader.load(getClass().getResource("mainmenu.fxml"));
            primaryStage.setScene(new Scene(root));         
            primaryStage.setTitle("recipe");
            primaryStage.show();
//          primaryStage.setResizable(false);
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        launch(args);
    }
}

控制器：

package application;

import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class Controller {
    private static int toIndex(Integer value) {
        return value == null ? 0 : value;
    }
    @FXML
    private Label food;
    @FXML
    private GridPane grid;

    @FXML
    private void clickmainmenu(MouseEvent event) {

        try {
            Parent koreanfood = FXMLLoader.load(getClass().getResource("koreanfood.fxml"));
            Scene scene = new Scene(koreanfood);
            Stage primaryStage = (Stage)((Node) event.getSource()).getScene().getWindow();

            Node node = (Node) event.getSource();
            Parent p = node.getParent();

            while (p != grid) {
                node = p;
                p = p.getParent();
            }

            int row = toIndex(GridPane.getRowIndex(node));
            int column = toIndex(GridPane.getColumnIndex(node));
            System.out.println("r : "+row+" c : "+column);
            primaryStage.setScene(scene);
            primaryStage.setTitle("recipe");
            if(row==0) {
                switch(column) {
                case 0:
                    food.setText("한식");
                    break;
                case 1:
                    food.setText("중식");
                    break;
                case 2:
                    food.setText("일식");
                    break;
                case 3:
                    food.setText("양식");
                    break;      
                }
            }
            else if(row==1) {
                switch(column) {
                case 0:
                    food.setText("분식");
                    break;
                case 1:
                    food.setText("야식");
                    break;
                case 2:
                    food.setText("랜덤");
                    break;
                case 3:
                    food.setText("ㅋ");
                    break;      
                }
            }           


        } catch(Exception e) {
            e.printStackTrace();
        }

    }
    @FXML
    private void clickfoodmenu(MouseEvent event) {
        try {
            Parent cookingrecipe = FXMLLoader.load(getClass().getResource("cookingrecipe.fxml"));
            Scene scene = new Scene(cookingrecipe);

            Stage primaryStage = (Stage)((Node) event.getSource()).getScene().getWindow();

            primaryStage.setScene(scene);
            primaryStage.setTitle("recipe");
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
    @FXML
    private void clickBackMain(MouseEvent event) {
        try {
            Parent koreanfood = FXMLLoader.load(getClass().getResource("mainmenu.fxml"));
            Scene scene = new Scene(koreanfood);

            Stage primaryStage = (Stage)((Node) event.getSource()).getScene().getWindow();

            primaryStage.setScene(scene);
            primaryStage.setTitle("recipe");
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
    @FXML
    private void clickBackKor(MouseEvent event) {
        try {
            Parent mainmenu = FXMLLoader.load(getClass().getResource("koreanfood.fxml"));
            Scene scene = new Scene(mainmenu);

            Stage primaryStage = (Stage)((Node) event.getSource()).getScene().getWindow();

            primaryStage.setScene(scene);
            primaryStage.setTitle("recipe");
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}

mainmenu.fxml：

 <?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 prefHeight="600.0" prefWidth="800.0" style="-fx-background-color: yellow;" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.Controller">
   <children>
      <Label layoutX="300.0" layoutY="47.0" prefHeight="94.0" prefWidth="220.0" text="뭐먹어">
         <font>
            <Font size="72.0" />
         </font>
      </Label>
      <GridPane fx:id="grid" hgap="30.0" layoutX="70.0" layoutY="200.0" prefHeight="320.0" prefWidth="682.0" vgap="30.0">
        <columnConstraints>
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
          <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
          <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        </columnConstraints>
        <rowConstraints>
          <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
          <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        </rowConstraints>
         <children>
            <AnchorPane onMouseClicked="#clickmainmenu" prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;">
               <children>
                  <ImageView fitHeight="101.0" fitWidth="103.0" layoutX="27.0" layoutY="7.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@../../../resources/iconfinder_Food_C226_2427886.png" />
                     </image></ImageView>
                  <Label layoutX="54.0" layoutY="119.0" text="한식">
                     <font>
                        <Font size="21.0" />
                     </font></Label>
               </children>
            </AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" GridPane.columnIndex="1">
               <children>
                  <Button layoutY="1.0" mnemonicParsing="false" onMouseClicked="#clickmainmenu" prefHeight="123.0" prefWidth="119.0" style="-fx-background-color: white;" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0" />
                  <ImageView fitHeight="114.0" fitWidth="116.0" layoutX="14.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@../../../resources/dim-sum.png" />
                     </image>
                  </ImageView>
                  <Label layoutX="54.0" layoutY="119.0" text="중식">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
               </children>
            </AnchorPane>
            <AnchorPane onMouseClicked="#clickmainmenu" prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.columnIndex="2">
               <children>
                  <Label layoutX="51.0" layoutY="121.0" text="일식">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
                  <ImageView fitHeight="128.0" fitWidth="122.0" layoutX="13.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@../../../resources/iconfinder_Food_C212_2427856.png" />
                     </image>
                  </ImageView>
               </children>
            </AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.columnIndex="3">
               <children>
                  <ImageView fitHeight="114.0" fitWidth="114.0" layoutX="17.0" pickOnBounds="true" preserveRatio="true" />
                  <Label layoutX="51.0" layoutY="121.0" text="양식">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
               </children></AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.rowIndex="1">
               <children>
                  <ImageView fitHeight="114.0" fitWidth="114.0" layoutX="17.0" pickOnBounds="true" preserveRatio="true" />
                  <Label layoutX="51.0" layoutY="114.0" text="분식">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
               </children></AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.columnIndex="1" GridPane.rowIndex="1">
               <children>
                  <ImageView fitHeight="114.0" fitWidth="114.0" layoutX="21.0" pickOnBounds="true" preserveRatio="true" />
                  <Label layoutX="51.0" layoutY="114.0" text="야식">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
               </children></AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.columnIndex="2" GridPane.rowIndex="1">
               <children>
                  <ImageView fitHeight="114.0" fitWidth="114.0" layoutX="17.0" pickOnBounds="true" preserveRatio="true" />
                  <Label layoutX="51.0" layoutY="114.0" text="랜덤">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
               </children></AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.columnIndex="3" GridPane.rowIndex="1">
               <children>
                  <ImageView fitHeight="114.0" fitWidth="130.0" layoutX="11.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@../../../resources/food.png" />
                     </image></ImageView>
                  <Label layoutX="10.0" layoutY="119.0" text="너만의 레시피">
                     <font>
                        <Font size="21.0" />
                     </font>
                  </Label>
               </children></AnchorPane>
         </children>
      </GridPane>
   </children>
</AnchorPane>

koreanfood.fxml：

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

<?import javafx.scene.image.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane prefHeight="600.0" prefWidth="800.0" style="-fx-background-color: yellow;" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.Controller">
   <children>
      <Label fx:id="food" layoutX="327.0" layoutY="14.0" prefHeight="99.0" prefWidth="193.0" text=" 한식">
         <font>
            <Font size="70.0" />
         </font>
      </Label>
      <GridPane hgap="20.0" layoutX="61.0" layoutY="121.0" prefHeight="448.0" prefWidth="678.0" vgap="20.0">
        <columnConstraints>
          <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
          <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        </columnConstraints>
        <rowConstraints>
          <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
          <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        </rowConstraints>
         <children>
            <AnchorPane onMouseClicked="#clickfoodmenu" prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;">
               <children>
                  <ImageView fitHeight="99.0" fitWidth="121.0" layoutX="17.0" layoutY="14.0" pickOnBounds="true" preserveRatio="true" />
                  <Label layoutX="54.0" layoutY="104.0" prefHeight="29.0" prefWidth="58.0" text="111" />
               </children>
            </AnchorPane>
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.rowIndex="1" />
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.rowIndex="2" />
            <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: white;" GridPane.columnIndex="1" />
         </children>
      </GridPane>
      <ImageView fitHeight="72.0" fitWidth="132.0" layoutX="32.0" layoutY="24.0" onMouseClicked="#clickBackMain" pickOnBounds="true" preserveRatio="true">
         <image>
            <Image url="@../../../resources/reply%20(2).png" />
         </image>
      </ImageView>
   </children>
</AnchorPane>

错误：

java.lang.NullPointerException
    at application.Controller.clickmainmenu(Controller.java:53)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.reflect.misc.Trampoline.invoke(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.reflect.misc.MethodUtil.invoke(Unknown Source)
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
    at javafx.fxml.FXMLLoader$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:54)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3470)
    at javafx.scene.Scene$ClickGenerator.access$8100(Scene.java:3398)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3766)
    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$MouseEventNotification.run(GlassViewEventHandler.java:394)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$353(GlassViewEventHandler.java:432)
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
    at com.sun.glass.ui.View.notifyMouse(View.java:937)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Unknown Source)

“ food.setText（“”）“是Controller.java:53

有人可以帮助我吗？