使用 JavaFX 切换场景时出现 InvocationTargetException
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【中文标题】使用 JavaFX 切换场景时出现 InvocationTargetException【英文标题】：InvocationTargetException while switching scenes with JavaFX 【发布时间】：2017-09-11 21:06:32 【问题描述】：我正在使用 JavaFX 并使用 .fxml 文件和相关的控制器类，在场景之间移动并具有按钮等功能。
我的 MainMenuController 关注我正在开发的游戏的菜单。 MainController 与我要加载的游戏板有关。但是每当我按下“启动游戏”按钮时，我都会收到这些错误：
javafx.fxml.LoadException:
/C:/.../bin/client/ui/Main.fxml
cause: java.lang.NullPointerException
where:
/C:/.../bin/client/ui/Main.fxml
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(Unknown Source)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(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.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$354(Unknown Source)
at com.sun.javaenter code herefx.tk.quantum.QuantumToolkit.runWithoutRenderLock(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.notifyMouse(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
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)
... 49 more
Caused by: java.lang.NullPointerException: Root cannot be null
at javafx.scene.Scene.<init>(Unknown Source)
at javafx.scene.Scene.<init>(Unknown Source)
at client.ui.MainMenuController.handleButtonAction(MainMenuController.java:251)
... 58 more
对我来说，似乎是 MainController 导致了问题，并且 因此阻止 Main.fxml 加载。
这是 MainMenuController 的方法，其中“launchGame”应该切换到以 Main.fxml 为根的新场景（last else if(...) 指令）：
@FXML
private void handleButtonAction(ActionEvent e)
Stage stage = null;
Parent root = null;
try
if (e.getSource() == leaveBrowserButton)
stage = (Stage) leaveBrowserButton.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("PlayGameSelection.fxml"));
if (e.getSource() == connect1Button)
stage = (Stage) connect1Button.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("Lobby.fxml"));
StartUI.getClient().connect(0);
if (e.getSource() == connect2Button)
StartUI.getClient().connect(1);
if (e.getSource() == connect3Button)
StartUI.getClient().connect(2);
if (e.getSource() == playGame)
stage = (Stage) playGame.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("PlayGameSelection.fxml"));
else if (e.getSource() == login)
stage = (Stage) login.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("MainMenu.fxml"));
else if (e.getSource() == createProfile)
stage = (Stage) createProfile.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("CreateNewPlayer.fxml"));
else if (e.getSource() == goToMainMenu)
stage = (Stage) goToMainMenu.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("MainMenu.fxml"));
else if (e.getSource() == goToCreateNewPlayer)
stage = (Stage) goToCreateNewPlayer.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("CreateNewPlayer.fxml"));
else if (e.getSource() == backToLogin)
stage = (Stage) backToLogin.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("Login.fxml"));
else if (e.getSource() == manageProfile)
stage = (Stage) manageProfile.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("ManagePlayer.fxml"));
else if (e.getSource() == backToGame)
stage = (Stage) backToGame.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("Main.fxml"));
else if (e.getSource() == backToMain || e.getSource() == goBackButton)
stage = (Stage) backToMain.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("MainMenu.fxml"));
else if (e.getSource() == playLocalGame)
stage = (Stage) playLocalGame.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("Browser.fxml"));
else if (e.getSource() == launchGame)
stage = (Stage) launchGame.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("Main.fxml"));
StartGameMessage startGame =
new StartGameMessage(StartUI.getClient().getGamestate().whosTurnIsIt(), false, 0);
StartUI.getClient().addMessage(startGame);
else
stage = (Stage) playGame.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource(e.getClass().getName()));
catch (Exception e1)
System.out.println(e1.getMessage());
System.out.println(e1);
System.out.println("cause: " + e1.getCause());
System.out.println("where: " + e1.getLocalizedMessage());
System.out.println(e1.getStackTrace());
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
我在 Main.fxml 文件中将控制器设置为 MainController，所以我看不到那里有问题：
<AnchorPane fx:id="anchorPane" prefHeight="720.0" prefWidth="1200.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="client.ui.MainController">
这里是我的 MainController：
package client.ui;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.ResourceBundle;
import client.domain.DevelopmentCard;
import client.domain.NobleTile;
import javafx.animation.PauseTransition;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.control.SplitPane;
import javafx.scene.effect.ColorAdjust;
import javafx.scene.effect.DropShadow;
import javafx.scene.effect.Glow;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.text.Text;
import javafx.stage.Stage;
import javafx.util.Duration;
import networkcommunication.domain.ActionTakeThreeTokens;
import networkcommunication.domain.ActionTakeTwoTokens;
import server.application.GameController;
public class MainController implements Initializable, Repaintable
@FXML
protected ImageView top1;
@FXML
protected ImageView top2;
@FXML
protected ImageView top3;
@FXML
protected ImageView top4;
@FXML
protected ImageView center1;
@FXML
protected ImageView center2;
@FXML
protected ImageView center3;
@FXML
protected ImageView center4;
@FXML
protected ImageView bottom1;
@FXML
protected ImageView bottom2;
@FXML
protected ImageView bottom3;
@FXML
protected ImageView bottom4;
@FXML
protected ImageView tokenRed7;
@FXML
protected ImageView tokenBlack7;
@FXML
protected ImageView tokenBlue7;
@FXML
protected ImageView tokenYellow5;
@FXML
protected ImageView tokenGreen7;
@FXML
protected ImageView tokenWhite7;
@FXML
protected ImageView noble1;
@FXML
protected ImageView noble2;
@FXML
protected ImageView noble3;
@FXML
protected ImageView noble4;
@FXML
protected ImageView noble5;
@FXML
protected ImageView reserve1;
@FXML
protected ImageView reserve2;
@FXML
protected ImageView reserve3;
@FXML
protected ImageView buy1;
@FXML
protected AnchorPane anchorPane;
@FXML
protected ImageView currentPosition;
@FXML
protected VBox buyBox;
@FXML
protected Button reserve;
@FXML
protected Button buy;
@FXML
protected Button goToGameMenu;
@FXML
protected Button playGame;
@FXML
protected Button playLocalGame;
@FXML
protected Button backToMain;
@FXML
protected Text counterGameYellowToken;
@FXML
protected Label yellowGameLabel;
@FXML
protected Label blackGameLabel;
@FXML
protected Label blueGameLabel;
@FXML
protected Label greenGameLabel;
@FXML
protected Label whiteGameLabel;
@FXML
protected Label redGameLabel;
@FXML
protected Label yellowOwnLabel;
@FXML
protected Label blackOwnLabel;
@FXML
protected Label blueOwnLabel;
@FXML
protected Label greenOwnLabel;
@FXML
protected Label whiteOwnLabel;
@FXML
protected Label redOwnLabel;
@FXML
protected CheckBox checkBox;
@FXML
protected ColorAdjust colorConstant = new ColorAdjust();
@FXML
protected ImageView optionPreviewCard;
@FXML
protected HBox buyHbox;
private int[] counter;
private int[] saveInt = new int[] 0, 0, 0, 0, 0, 0;
private int[] saveForThree = new int[] 0, 0, 0, 0, 0, 0;
private int[] saveSpecificTokens = new int[] 0, 0, 0, 0, 0, 0;
private int[] previousCounter = new int[] 0, 0, 0, 0, 0, 0;
private Image forReserve;
protected List<ImageView> devCardsLevelO;
protected List<ImageView> devCardsLevelOO;
protected List<ImageView> devCardsLevelOOO;
protected List<ImageView> yellowTokens;
protected List<ImageView> blackTokens;
protected List<ImageView> redTokens;
protected List<ImageView> blueTokens;
protected List<ImageView> greenTokens;
protected List<ImageView> whiteTokens;
protected List<ImageView> nobleTilesImgV;
protected List<DevelopmentCard> devCards1;
protected List<DevelopmentCard> devCards2;
protected List<DevelopmentCard> devCards3;
protected List<NobleTile> nobleTiles;
private List<Label> pressableTokens = new ArrayList<>();
private List<Label> ownTokens = new ArrayList<>();
@FXML
protected Label player2view;
@FXML
protected SplitPane enemySplitPane;
@FXML
protected ImageView enemyReserve1;
@FXML
protected ImageView enemyReserve2;
@FXML
protected ImageView enemyReserve3;
@FXML
protected HBox enemyReserveBox;
@FXML
public void changeTokenCount(MouseEvent e) throws IOException
pressableTokens.addAll(
Arrays.asList(blackGameLabel, whiteGameLabel, redGameLabel, greenGameLabel, blueGameLabel));
ownTokens.addAll(
Arrays.asList(blackOwnLabel, whiteOwnLabel, redOwnLabel, greenOwnLabel, blueOwnLabel));
for (int cycle = 0; cycle < pressableTokens.size(); cycle++)
if (e.getSource() == pressableTokens.get(cycle) && counter[cycle] < 2)
previousCounter = counter.clone();
counter[cycle]++;
pressableTokens.get(cycle).setText("x" + Integer.toString(5 - counter[cycle]));
ownTokens.get(cycle).setText("x" + Integer.toString(counter[cycle]));
if (counter[cycle] == 2 && lastEntryPosition() == cycle)
System.out.println("I just pressed x" + pressableTokens.get(cycle).getId() + " twice!");
if (counter[cycle] == 2)
pressableTokens.get(cycle).setDisable(true);
if (tookThreeDifferentTokens())
System.out.println("I just took three tokens");
ActionTakeThreeTokens tookThree = new ActionTakeThreeTokens(
StartUI.getClient().getGamestate().whosTurnIsIt(), saveSpecificTokens);
StartUI.getClient().addMessage(tookThree);
System.out.println(Arrays.toString(saveSpecificTokens));
saveSpecificTokens = new int[] 0, 0, 0, 0, 0, 0;
System.out.println("I just pressed: " + pressableTokens.get(cycle).getId());
break;
for (
int i = 0; i < 4; i++)
setBrightness(devCardsLevelO.get(i), -0.2);
setBrightness(devCardsLevelOO.get(i), -0.2);
setBrightness(devCardsLevelOOO.get(i), -0.2);
colorConstant.setBrightness(-0.2);
if (devCards1.get(i).getPriceDiamond() <= counter[2]
&& devCards1.get(i).getPriceEmerald() <= counter[4]
&& devCards1.get(i).getPriceSapphire() <= counter[5]
&& devCards1.get(i).getPriceRuby() <= counter[3]
&& devCards1.get(i).getPriceOnyx() <= counter[1])
setBrightness(devCardsLevelO.get(i), 0.35);
if (devCards2.get(i).getPriceDiamond() <= counter[2]
&& devCards2.get(i).getPriceEmerald() <= counter[4]
&& devCards2.get(i).getPriceSapphire() <= counter[5]
&& devCards2.get(i).getPriceRuby() <= counter[3]
&& devCards2.get(i).getPriceOnyx() <= counter[1])
setBrightness(devCardsLevelOO.get(i), 0.35);
if (devCards3.get(i).getPriceDiamond() <= counter[2]
&& devCards3.get(i).getPriceEmerald() <= counter[4]
&& devCards3.get(i).getPriceSapphire() <= counter[5]
&& devCards3.get(i).getPriceRuby() <= counter[3]
&& devCards3.get(i).getPriceOnyx() <= counter[1])
setBrightness(devCardsLevelOOO.get(i), 0.35);
System.out.println("counter: " + Arrays.toString(counter) + "\tpreviousCounter: "
+ Arrays.toString(previousCounter) + "\tsaveThree: " + Arrays.toString(saveForThree)
+ "\tYou took those different tokens: " + Arrays.toString(saveSpecificTokens));
System.out.println("");
@FXML
public void manageCardClick(MouseEvent e) throws IOException
if (e.getSource() == reserve)
setReserveImage(forReserve);
buyBox.setVisible(false);
counter[0]++;
yellowGameLabel.setText("x" + Integer.toString(4 - counter[0]));
yellowOwnLabel.setText("x" + Integer.toString(counter[0]));
else if (e.getSource() == buy)
setBuyImage(forReserve);
buyBox.setVisible(false);
blackGameLabel
.setText("x" + Integer.toString(5 - counter[1] + devCards1.get(1).getPriceOnyx()));
blackOwnLabel.setText("x" + Integer.toString(counter[1] - devCards1.get(1).getPriceOnyx()));
redGameLabel
.setText("x" + Integer.toString(5 - counter[3] + devCards1.get(1).getPriceRuby()));
redOwnLabel.setText("x" + Integer.toString(counter[3] - devCards1.get(1).getPriceRuby()));
blueGameLabel
.setText("x" + Integer.toString(5 - counter[5] + devCards1.get(1).getPriceSapphire()));
blueOwnLabel
.setText("x" + Integer.toString(counter[5] - devCards1.get(1).getPriceSapphire()));
greenGameLabel
.setText("x" + Integer.toString(5 - counter[4] + devCards1.get(1).getPriceEmerald()));
greenOwnLabel
.setText("x" + Integer.toString(counter[4] - devCards1.get(1).getPriceEmerald()));
whiteGameLabel
.setText("x" + Integer.toString(5 - counter[2] + devCards1.get(1).getPriceDiamond()));
whiteOwnLabel
.setText("x" + Integer.toString(counter[2] + devCards1.get(1).getPriceDiamond()));
private int lastEntryPosition()
int out = -1;
for (int i = 0; i < counter.length; i++)
if (counter[i] - previousCounter[i] != 0)
out = i;
break;
System.out.println("Position: " + out);
return out;
private boolean tookThreeDifferentTokens()
int countToThree = 0;
for (int i = 0; i < counter.length; i++)
if (counter[i] - saveForThree[i] != 0)
countToThree++;
System.out.println(countToThree);
if (countToThree == 3)
for (int j = 0; j < counter.length; j++)
saveSpecificTokens[j] = counter[j] - saveForThree[j];
saveForThree = counter.clone();
return true;
else
return false;
@FXML
protected void handleButtonAction(ActionEvent e) throws IOException
Stage stage;
Parent root;
if (e.getSource() == goToGameMenu)
stage = (Stage) goToGameMenu.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("GameMenu.fxml"));
else
stage = (Stage) playGame.getScene().getWindow();
root = FXMLLoader.load(getClass().getResource("Main.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
public void hideImgView(ImageView imgV)
imgV.setVisible(false);
public void selectDevCard(ImageView imgV)
if (imgV.getScaleX() == 1.0)
imgV.setEffect(new Glow(0.7));
imgV.setScaleX(1.15);
imgV.setScaleY(1.15);
else
DropShadow shadow = new DropShadow();
imgV.setEffect(shadow);
imgV.setScaleX(1.0);
imgV.setScaleY(1.0);
public void setReserveImage(Image im) throws IOException
if (reserve1.getImage() == null)
reserve1.setImage(im);
setNewCard();
else if (reserve2.getImage() == null)
reserve2.setImage(im);
setNewCard();
else if (reserve3.getImage() == null)
reserve3.setImage(im);
setNewCard();
else
Stage warning = new Stage();
Parent root = FXMLLoader.load(getClass().getResource("Warning.fxml"));
Scene warningScene = new Scene(root);
warning.setScene(warningScene);
warning.show();
PauseTransition delay = new PauseTransition(Duration.seconds(5));
delay.setOnFinished(e -> warning.close());
delay.play();
public void setBuyImage(Image im)
ImageView buyView = new ImageView(optionPreviewCard.getImage());
buyView.fitHeightProperty().bind(buyHbox.heightProperty());
buyView.setPreserveRatio(true);
buyHbox.getChildren().add(buyView);
setNewCard();
public void setImageEffect(ImageView imageView, double brightness)
ColorAdjust colorAdjust = new ColorAdjust();
colorAdjust.setBrightness(brightness);
imageView.addEventFilter(MouseEvent.MOUSE_ENTERED, e -> imageView.setEffect(colorAdjust));
imageView.addEventFilter(MouseEvent.MOUSE_EXITED, e -> imageView.setEffect(colorConstant));
public void setBrightness(ImageView imageView, double brightness)
ColorAdjust colorAdjust = new ColorAdjust();
colorAdjust.setBrightness(brightness);
imageView.setEffect(colorAdjust);
private void setNewCard()
for (int i = 0; i < 4; i++)
if (devCardsLevelO.get(i).getImage() == null)
devCardsLevelO.get(i)
.setImage(new Image(this.getClass().getResourceAsStream(devCards1.get(4).getPath())));
if (devCardsLevelOO.get(i).getImage() == null)
devCardsLevelOO.get(i)
.setImage(new Image(this.getClass().getResourceAsStream(devCards2.get(4).getPath())));
if (devCardsLevelOOO.get(i).getImage() == null)
devCardsLevelOOO.get(i)
.setImage(new Image(this.getClass().getResourceAsStream(devCards3.get(4).getPath())));
@Override
public void initialize(URL location, ResourceBundle resources)
StartUI.getRepaintThread().addInterface(this);
this.counter = new int[6];
this.saveInt = new int[6];
for (int i = 0; i < this.counter.length; i++)
this.counter[i] = 0;
this.saveInt[i] = 0;
this.devCardsLevelO = new ArrayList<ImageView>();
this.devCardsLevelOO = new ArrayList<ImageView>();
this.devCardsLevelOOO = new ArrayList<ImageView>();
this.yellowTokens = new ArrayList<ImageView>();
this.blackTokens = new ArrayList<ImageView>();
redTokens = new ArrayList<ImageView>();
this.blueTokens = new ArrayList<ImageView>();
this.greenTokens = new ArrayList<ImageView>();
this.whiteTokens = new ArrayList<ImageView>();
this.nobleTilesImgV = new ArrayList<ImageView>();
this.devCards1 = new ArrayList<DevelopmentCard>();
this.devCards2 = new ArrayList<DevelopmentCard>();
this.devCards3 = new ArrayList<DevelopmentCard>();
this.nobleTiles = new ArrayList<NobleTile>();
this.devCardsLevelO.addAll(Arrays.asList(bottom1, bottom2, bottom3, bottom4));
this.devCardsLevelOO.addAll(Arrays.asList(center1, center2, center3, center4));
this.devCardsLevelOOO.addAll(Arrays.asList(top1, top2, top3, top4));
this.nobleTilesImgV.addAll(Arrays.asList(noble1, noble2, noble3, noble4, noble5));
for (int i = 0; i < devCardsLevelO.size(); i++)
int k = i;
setImageEffect(devCardsLevelO.get(k), 0.2);
devCardsLevelO.get(i).setSmooth(true);
devCardsLevelO.get(i).setOnMouseClicked(e ->
forReserve = devCardsLevelO.get(k).getImage();
optionPreviewCard.setImage(forReserve);
buyBox.setVisible(true);
devCards1.get(k).setSelectable(false);
devCardsLevelO.get(k).setImage(null);
);
setImageEffect(devCardsLevelOO.get(k), 0.2);
devCardsLevelOO.get(k).setOnMouseClicked(e ->
buyBox.setVisible(true);
forReserve = devCardsLevelOO.get(k).getImage();
optionPreviewCard.setImage(forReserve);
devCards2.get(k).setSelectable(false);
devCardsLevelOO.get(k).setImage(null);
);
setImageEffect(devCardsLevelOOO.get(k), 0.2);
devCardsLevelOOO.get(k).setOnMouseClicked(e ->
buyBox.setVisible(true);
forReserve = devCardsLevelOOO.get(k).getImage();
optionPreviewCard.setImage(forReserve);
devCards3.get(k).setSelectable(false);
devCardsLevelOOO.get(k).setImage(null);
);
@Override
public void update()
Platform.runLater(new Runnable()
@Override
public void run()
devCards1 = StartUI.getClient().getGamestate().getDevelopmentCardsLevelO();
devCards2 = StartUI.getClient().getGamestate().getDevelopmentCardsLevelOO();
devCards3 = StartUI.getClient().getGamestate().getDevelopmentCardsLevelOOO();
nobleTiles = StartUI.getClient().getGamestate().getNobleTiles();
for (int i = 0; i < nobleTilesImgV.size(); i++)
if (nobleTiles.get(i).isSelectable())
nobleTilesImgV.get(i).setImage(
new Image(this.getClass().getResourceAsStream(nobleTiles.get(i).getPath())));
for (int i = 0; i < devCardsLevelO.size(); i++)
if (devCards1.get(i).isSelectable())
devCardsLevelO.get(i).setImage(
new Image(this.getClass().getResourceAsStream(devCards1.get(i).getPath())));
for (int i = 0; i < devCardsLevelOO.size(); i++)
if (devCards2.get(i).isSelectable())
devCardsLevelOO.get(i).setImage(
new Image(this.getClass().getResourceAsStream(devCards2.get(i).getPath())));
for (int i = 0; i < devCardsLevelOOO.size(); i++)
if (devCards3.get(i).isSelectable())
devCardsLevelOOO.get(i).setImage(
new Image(this.getClass().getResourceAsStream(devCards3.get(i).getPath())));
);
我在这个漏洞上工作了一天，但仍然无法弄清楚是什么导致了这个错误。它开始变得非常令人沮丧，如果我们能解决这个问题，那就太棒了:)
【问题讨论】：
第一个错误告诉您在尝试加载Main.fxml 时出现问题。由于加载失败，您有一个空根，并且您发布的异常表明场景无法加载空根。能否将e1.printStackTrace() 添加到catch 子句catch (Exception e1) ，再次运行并发布异常？
感谢您的快速回答！哇！我实际上可以用 e1.printStackTrace() 解决这个问题，因为它给了我一个额外的错误和问题的确切行。我没有在 System.out.print(e1.getStackTrace()) 中看到这一点。非常感谢！ :)
【参考方案1】：
通过阅读您的 StackTrace，我看到以下行：Caused by: java.lang.NullPointerException: Root cannot be null。
这意味着您不能将 Root 设置为空。
在您的一个 sn-ps 中，您有以下几行：
@FXML
private void handleButtonAction(ActionEvent e)
Stage stage = null;
Parent root = null;
您正在为您分配 Parent 以具有空值，这会导致您得到 NullPointException。我建议您删除分配给Parent 的null 值。
【讨论】：
感谢您的快速回答！就是 root 保持为空。但是需要这些行来初始化阶段和根。问题是，应该为根分配 FXMLLoader.load(...)。这适用于我想切换到的所有其他场景，除了 Main.fxml。 FXMLLoader.load(getClass().getResource("Main.fxml"));返回 null 但我不明白为什么。以上是关于使用 JavaFX 切换场景时出现 InvocationTargetException的主要内容，如果未能解决你的问题，请参考以下文章
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