当我执行MouseClickEvent时，我想获取GridPane的索引。我在GridPane中的AnchorPane上创建了clickevent。我成功地在点击时将main menu. fxml更改为大韩食品.fxml。但是我想获得GridPane的索引，因为当我在GridPane中单击另一个AnchorPane时，我想在一个.fxml上做同样的事情。
我试过这个方法还有这个方法还有这个方法
但是getRowIndex（）和getColumnIndex（）总是返回null
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);
}
}
Controller.java：
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 {
@FXML
private Label food;
@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();
Integer row = GridPane.getRowIndex((Node)event.getSource() );
int column=GridPane.getColumnIndex((Node)event.getSource() );
System.out.println("r : "+row+"c : "+column);
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;
}
}
primaryStage.setScene(scene);
primaryStage.setTitle("recipe");
} 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();
}
}
}
主菜单. 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>
<GridPane 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 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>
<Label layoutX="300.0" layoutY="47.0" prefHeight="94.0" prefWidth="220.0" text="뭐먹어">
<font>
<Font size="72.0" />
</font>
</Label>
</children>
</AnchorPane>
韩国食品. 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="146.0">
<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:25)
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)
我该怎么办？有人能帮我吗？？
除非您初始化此属性，否则rowIndex/列Index为null。没有必要指定这些属性，因为GridPane默认将它们视为0。
另请注意，MouseEvent. source包含添加事件处理程序的节点，因此
（0,0），为了减小fxml大小，SceneBuilder不指定值，因为对布局的影响是相同的，导致值为null。GridPane的子节点，而是GridPane的子节点，因此既没有指定rowIndex也没有指定列Index。（除了按钮之外，最好使用onAction事件；不过这是一个ActionEvent。）尽管如此，你还是可以通过
GridPane的子节点。null视为0private static int toIndex(Integer value) {
return value == null ? 0 : value;
}
@FXML
private GridPane grid;
<GridPane fx:id="grid" hgap="30.0" layoutX="70.0" layoutY="200.0" prefHeight="320.0" prefWidth="682.0" vgap="30.0">
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));
