Null 포인터 JavaFX 대화 상자를 닫을 때 예외가 발생했습니다.

Question

기본 단계부터 시작하는 간단한 프로그램이 있습니다. 그런 다음 대화 상자를 시작하는 메뉴 항목을 선택합니다. 대화 상자에 아무 것도하지 않고 현재 스테이지를 닫는 버튼이 있습니다. 나는 대화가 닫히고, 초점이 초기 단계로 돌아갈 것이라고 기대하고있었습니다. 그러나 Create Game 버튼을 클릭하면 null 포인터 예외가 발생합니다. 나는 Java에 상당히 익숙하지 않고 아마 명백한 것을 놓치고있을 것이다. 도와주세요.

HWFX.JAVA 

package Main; 

import java.util.Date; 

import javafx.application.Application; 
import javafx.collections.FXCollections; 
import javafx.collections.ObservableList; 
import javafx.fxml.FXMLLoader; 
import javafx.scene.Group; 
import javafx.scene.Parent; 
import javafx.scene.Scene; 
import javafx.scene.control.TableView; 
import javafx.scene.control.TextField; 
import javafx.scene.layout.GridPane; 
import javafx.scene.layout.VBox; 
import javafx.stage.Stage; 

public class HWFX extends Application { 

    public static void main(String[] args) { 
     // TODO Auto-generated method stub 
    launch(args); 
    } 

    @Override 
    public void start(Stage primaryStage) throws Exception { 
     // TODO Auto-generated method stub 
    FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/Main.fxml")); 
    Parent root = loader.load(); 
    MainController controller = (MainController) loader.getController(); 
    controller.init(primaryStage); 

    Scene scene = new Scene(root,600,400); 
    scene.getStylesheets().add("/fxml/styles/mainfx.css"); 

    primaryStage.setScene(scene); 
    primaryStage.setTitle("Hello World FX"); 
    primaryStage.show(); 

    } 

MainController.java

package Main; 

import java.io.File; 
import java.io.IOException; 
import java.net.URL; 
import java.util.ResourceBundle; 

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.control.Button; 
import javafx.scene.control.TextField; 
import javafx.stage.FileChooser; 
import javafx.stage.Stage; 
import javafx.stage.StageStyle; 

import java.sql.*; 

import javax.sql.*; 

import oracle.jdbc.*; 
import oracle.jdbc.pool.OracleDataSource; 

public class MainController implements Initializable { 

    private Stage stage; 
    @FXML 
    javafx.scene.layout.AnchorPane AnchorPane; 
    @FXML 
    javafx.scene.layout.GridPane GridPane; 
    @FXML 
    javafx.scene.layout.GridPane GridPaneMain; 
    @FXML 
    Button TestButton1; 
    Button TestButton2; 
    Button TestButton3; 
    @FXML 
    javafx.scene.control.TextField PlayerName; 


    @Override 
    public void initialize(URL arg0, ResourceBundle arg1) { 
     // TODO Auto-generated method stub 

    } 

    public void doExit() { 
     Platform.exit(); 
    } 

    public void openFile() { 
     FileChooser fileChooser = new FileChooser(); 
     fileChooser.setTitle("Open text file");  
     fileChooser.setInitialDirectory(new File(System.getProperty("user.home"))); 
     fileChooser.getExtensionFilters().addAll(
       new FileChooser.ExtensionFilter("Text Files","*.txt"), 
       new FileChooser.ExtensionFilter("All Files","*.*") 
       ); 
     File file = fileChooser.showOpenDialog(stage); 

     if (file != null){ 
      System.out.println("Choosen File: " + file); 
     } 
    } 

    public void ButtonClicked() throws SQLException { 
     System.out.println("Click!"); 
     final TextField F1 = new TextField(); 
     F1.setPromptText("F1"); 
     F1.setPrefColumnCount(10); 
     F1.getText(); 
//  javafx.scene.layout.GridPane.setConstraints(F1,10,10); 
     GridPaneMain.add(F1, 0, 0); 

     OracleDataSource ods = new OracleDataSource(); 

     // Set the user name, password, driver type and network protocol 
     ods.setUser("ppmcdev"); 
     ods.setPassword("ppmc"); 
     ods.setURL("jdbc:oracle:thin:@172.21.51.56:1521:INAVD"); 
     ods.setDriverType("oci8"); 
     ods.setNetworkProtocol("ipc"); 
     ods.setTNSEntryName("INAVD"); 

     // Retrieve a connection 
     Connection conn = ods.getConnection(); 
     getUserName(conn); 
     // Close the connection 
     conn.close(); 
     conn = null; 
    } 

     public void CreateGame(ActionEvent event) throws IOException { 
      System.out.println("Create Game Menu"); 
      CreateGameDialogController CreateGameDialog = new CreateGameDialogController(); 
      try { 
       CreateGameDialog.showCreateGameDialog(stage); 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
     } 

    public void init(Stage stage) { 
     // TODO Auto-generated method stub 
     this.stage = stage; 
    } 
} 

Main.fxml

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

<?import javafx.scene.input.*?> 
<?import javafx.geometry.*?> 
<?import javafx.scene.control.*?> 
<?import javafx.scene.layout.*?> 
<?import java.lang.*?> 
<?import javafx.scene.image.*?> 

<AnchorPane fx:id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Main.MainController"> 
    <children> 
     <BorderPane layoutX="-2.0" layoutY="-3.0" prefHeight="400.0" prefWidth="606.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0"> 
     <center> 
      <TextArea prefHeight="200.0" prefWidth="200.0" BorderPane.alignment="CENTER" /> 
     </center> 
     <top> 
      <MenuBar BorderPane.alignment="CENTER"> 
       <menus> 
       <Menu text="_File"> 
        <items> 
         <MenuItem onAction="#openFile" text="_Open"> 
          <accelerator> 
           <KeyCodeCombination alt="UP" code="O" control="DOWN" meta="UP" shift="UP" shortcut="UP" /> 
          </accelerator> 
         </MenuItem> 
        <MenuItem onAction="#doExit" text="E_xit"> 
          <accelerator> 
           <KeyCodeCombination alt="UP" code="X" control="DOWN" meta="UP" shift="UP" shortcut="UP" /> 
          </accelerator> 
         </MenuItem> 
        </items> 
       </Menu> 
        <Menu text="_Game"> 
        <items> 
         <MenuItem onAction="#CreateGame" text="_Create"> 
          <accelerator> 
           <KeyCodeCombination alt="DOWN" code="C" control="UP" meta="UP" shift="UP" shortcut="UP" /> 
          </accelerator></MenuItem> 
        </items> 
        </Menu> 
       </menus> 
      </MenuBar> 
     </top> 
     <bottom> 
      <Button mnemonicParsing="false" onAction="#ButtonClicked" text="ClickMeButton" BorderPane.alignment="CENTER" /> 
     </bottom> 
     </BorderPane> 
     <GridPane id="GridPane" fx:id="GridPane" layoutX="20.0" layoutY="70.0" prefHeight="68.0" prefWidth="594.0" AnchorPane.bottomAnchor="30.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="6.0"> 
     <columnConstraints> 
      <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" /> 
     </columnConstraints> 
     <rowConstraints> 
      <RowConstraints fillHeight="false" minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" /> 
     </rowConstraints> 
     <padding> 
      <Insets top="40.0" /> 
     </padding> 
     <children> 
      <Button id="TestButton1" alignment="TOP_LEFT" contentDisplay="BOTTOM" mnemonicParsing="false" prefHeight="22.0" prefWidth="94.0" text="Test Button 1" /> 
      <Button id="TestButton2" contentDisplay="BOTTOM" mnemonicParsing="false" prefHeight="25.0" prefWidth="91.0" text="Test Button 2"> 
       <GridPane.margin> 
        <Insets left="100.0" /> 
       </GridPane.margin> 
      </Button> 
      <Button id="addPlayer" fx:id="addPlayer" alignment="BASELINE_RIGHT" mnemonicParsing="false" onAction="#addPlayer" text="Add Player"> 
       <GridPane.margin> 
        <Insets left="300.0" /> 
       </GridPane.margin> 
      </Button> 
      <TextField fx:id="PlayerName" prefHeight="25.0" prefWidth="152.0" promptText="Player Name"> 
       <GridPane.margin> 
        <Insets left="400.0" /> 
       </GridPane.margin> 
      </TextField> 
     </children> 
     </GridPane> 
     <GridPane id="GridPaneMain" fx:id="GridPaneMain" gridLinesVisible="true" layoutY="29.0" prefHeight="308.0" prefWidth="600.0"> 
     <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> 
     <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> 
     </GridPane> 
    </children> 
</AnchorPane> 

CreateGameDialogController.java

package Main; 

import java.io.File; 
import java.io.IOException; 
import java.net.URL; 
import java.util.ResourceBundle; 

import javafx.application.Platform; 
import javafx.stage.Modality; 
import javafx.stage.Stage; 
import javafx.event.ActionEvent; 
import javafx.fxml.*; 
import javafx.scene.layout.*; 
import javafx.scene.*; 

public class CreateGameDialogController implements Initializable { 

    @FXML 
    private javafx.scene.layout.AnchorPane AnchorPane; 
    @FXML 
    private javafx.scene.control.Slider NumberOfPlayers; 

    private Stage myParent; 
    private Stage CreateGameDialogStage; 

    public void showCreateGameDialog(Stage parentStage) { 
    this.myParent = parentStage; 
    try { 
     CreateGameDialogStage = new Stage(); 
     AnchorPane page = (AnchorPane) FXMLLoader.load(CreateGameDialogController.class.getResource("/fxml/CreateGameDialog.fxml")); 
     Scene scene = new Scene(page); 
     CreateGameDialogStage.setScene(scene); 
     CreateGameDialogStage.setTitle("Create Game"); 
     CreateGameDialogStage.initOwner(this.myParent); 
     CreateGameDialogStage.initModality(Modality.WINDOW_MODAL); 
     CreateGameDialogStage.show(); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 

    } 

    public void CreateGame(ActionEvent event) { 
     try { 
     System.out.println("Create Game"); 
     CreateGameDialogStage.close(); 
     } catch (Exception e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

    @Override 
    public void initialize(URL location, ResourceBundle resources) { 
     // TODO Auto-generated method stub 

    } 

} 

CreateGameDialog.fxml

,536 내가 만들기 게임 버튼을 클릭하면

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

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

<AnchorPane id="AnchorPane" prefHeight="427.0" prefWidth="602.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Main.CreateGameDialogController"> 
    <children> 
     <BorderPane prefHeight="200.0" prefWidth="200.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0"> 
     <left> 
      <Pane prefHeight="427.0" prefWidth="257.0" BorderPane.alignment="CENTER"> 
       <children> 
        <Slider id="NumberOfPlayers" fx:id="NumberOfPlayers" blockIncrement="1.0" layoutX="14.0" layoutY="42.0" majorTickUnit="1.0" max="8.0" min="3.0" minorTickCount="0" orientation="VERTICAL" prefHeight="310.0" prefWidth="14.0" showTickLabels="true" showTickMarks="true" snapToTicks="true" value="1.0" /> 
        <Label alignment="CENTER" contentDisplay="CENTER" prefHeight="29.0" prefWidth="257.0" text="Select the Players" textAlignment="CENTER"> 
        <font> 
         <Font name="System Bold" size="14.0" /> 
        </font> 
        </Label> 
        <Button id="CreateGameButton" layoutX="79.0" layoutY="388.0" mnemonicParsing="false" onAction="#CreateGame" prefHeight="25.0" prefWidth="102.0" text="Create Game" /> 
       </children> 
      </Pane> 
     </left> 
     <right> 
      <ScrollPane prefHeight="427.0" prefWidth="360.0" BorderPane.alignment="CENTER" /> 
     </right> 
     </BorderPane> 
    </children> 
</AnchorPane> 

, 내가 얻을 :

Create Game 
java.lang.NullPointerException 
    at Main.CreateGameDialogController.CreateGame(CreateGameDialogController.java:47) 
    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$MethodHandler.invoke(Unknown Source) 
    at javafx.fxml.FXMLLoader$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.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$141(Unknown Source) 
    at com.sun.glass.ui.win.WinApplication$$Lambda$38/2075313.run(Unknown Source) 
    at java.lang.Thread.run(Unknown Source) 

Answer 1

MainController 내부 CreateGame()의 문제는이 라인에 있습니다

CreateGameDialogController CreateGameDialog = 새로운 CreateGameDialogController();

당신이 FXML 컨트롤러를 사용하는 대신 new을 사용하여 컨트롤러 객체를 생성하는, 항상 FXML을로드하고 FXMLoader에서 컨트롤러를 얻을

당신은 CreateGame() 내부 CreateGameDialog.fxml를로드 대신 FXML을로드하려고합니다 자체 컨트롤러에서. ProTip

- 사용 낙타 케이스

자바로 코딩하면서