splash屏幕沒有加載mainFxml文件

Question

即時嘗試使像這樣的SplashScreen SplashScreen，但我的代碼將不會加載mainFxml.fxml ...每一件事情工作良好的啓動屏幕加載好我認爲，但它後加載我得到這個錯誤：

`Exception in Application start method 
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException 
    at istehkakat.Istehkakat$3.changed(Istehkakat.java:163) 
    at istehkakat.Istehkakat$3.changed(Istehkakat.java:157) 
    at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:182) 
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81) 
    at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:105) 
    at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112) 
    at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:145) 
    at javafx.concurrent.Task.setState(Task.java:693) 
    at javafx.concurrent.Task$TaskCallable.lambda$call$443(Task.java:1420) 
    at javafx.concurrent.Task$TaskCallable$$Lambda$177/1990300023.run(Unknown Source) 
    at com.sun.javafx.application.PlatformImpl.lambda$null$164(PlatformImpl.java:292) 
    at com.sun.javafx.application.PlatformImpl$$Lambda$52/1527683020.run(Unknown Source) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(PlatformImpl.java:291) 
    at com.sun.javafx.application.PlatformImpl$$Lambda$51/1174361318.run(Unknown Source) 
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) 
    at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method) 
    at com.sun.glass.ui.gtk.GtkApplication.lambda$null$45(GtkApplication.java:126) 
    at com.sun.glass.ui.gtk.GtkApplication$$Lambda$42/1768305536.run(Unknown Source) 
    at java.lang.Thread.run(Thread.java:745) 
java.lang.reflect.InvocationTargetException 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:483) 
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:363) 
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:303) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:483) 
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767) 
Caused by: java.lang.RuntimeException: Exception in Application start method 
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:875) 
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$147(LauncherImpl.java:157) 
    at com.sun.javafx.application.LauncherImpl$$Lambda$54/1972439101.run(Unknown Source) 
    at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.NullPointerException 
    at istehkakat.Istehkakat.showMainStage(Istehkakat.java:130) 
    at istehkakat.Istehkakat.start(Istehkakat.java:103) 
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$153(LauncherImpl.java:821) 
    at com.sun.javafx.application.LauncherImpl$$Lambda$124/86108265.run(Unknown Source) 
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$166(PlatformImpl.java:323) 
    at com.sun.javafx.application.PlatformImpl$$Lambda$50/1717159510.run(Unknown Source) 
    at com.sun.javafx.application.PlatformImpl.lambda$null$164(PlatformImpl.java:292) 
    at com.sun.javafx.application.PlatformImpl$$Lambda$52/1527683020.run(Unknown Source) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(PlatformImpl.java:291) 
    at com.sun.javafx.application.PlatformImpl$$Lambda$51/1174361318.run(Unknown Source) 
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) 
    at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method) 
    at com.sun.glass.ui.gtk.GtkApplication.lambda$null$45(GtkApplication.java:126) 
    at com.sun.glass.ui.gtk.GtkApplication$$Lambda$42/1768305536.run(Unknown Source) 
    ... 1 more 
Exception running application istehkakat.Istehkakat 
Java Result: 1` 

我主要的Java類：

/* 
* To change this license header, choose License Headers in Project Properties. 
* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package istehkakat; 

import controller.MainFxmlController; 
import java.io.IOException; 
import javafx.animation.FadeTransition; 
import javafx.application.Application; 
import javafx.application.Preloader; 
import javafx.beans.value.ChangeListener; 
import javafx.beans.value.ObservableValue; 
import javafx.collections.ObservableList; 
import javafx.concurrent.Task; 
import javafx.concurrent.Worker; 
import javafx.event.ActionEvent; 
import javafx.event.EventHandler; 
import javafx.fxml.FXMLLoader; 
import javafx.geometry.Pos; 
import javafx.geometry.Rectangle2D; 
import javafx.scene.Parent; 
import javafx.scene.Scene; 
import javafx.scene.control.Label; 
import javafx.scene.control.ProgressBar; 
import javafx.scene.effect.DropShadow; 
import javafx.scene.image.Image; 
import javafx.scene.image.ImageView; 
import javafx.scene.layout.Pane; 
import javafx.scene.layout.VBox; 
import javafx.scene.web.WebView; 
import javafx.stage.Screen; 
import javafx.stage.Stage; 
import javafx.stage.StageStyle; 
import javafx.stage.WindowEvent; 
import javafx.util.Duration; 

/** 
* 
* @author combozo 
*/ 
public class Istehkakat extends Application { 

    private Pane splashLayout; 
    private ProgressBar loadProgress; 
    private Label progressText; 
    private Stage mainStage; 
    private static final int SPLASH_WIDTH = 676; 
    private static final int SPLASH_HEIGHT = 227; 

    @Override 
    public void init() { 
     ImageView splash = new ImageView(new Image(getClass().getResourceAsStream("/imgs/SplashScreenIll.png"))); 
     loadProgress = new ProgressBar(); 
     loadProgress.setPrefWidth(SPLASH_WIDTH - 20); 
     progressText = new Label("تحميل بيانات البرنامج ..."); 
     splashLayout = new VBox(); 
     splashLayout.getChildren().addAll(splash, loadProgress, progressText); 
     progressText.setAlignment(Pos.CENTER); 
     splashLayout.setStyle("-fx-padding: 5; -fx-background-color: cornsilk; -fx-border-width:5; -fx-border-color: linear-gradient(to bottom, chocolate, derive(chocolate, 50%));"); 
     splashLayout.setEffect(new DropShadow()); 
    } 

    @Override 
    public void start(Stage initStage) throws Exception { 
     notifyPreloader(new Preloader.StateChangeNotification(Preloader.StateChangeNotification.Type.BEFORE_START)); 
     final Task preloaderTask = new Task() { 
      @Override 
      protected Object call() throws InterruptedException { 
       updateMessage("Loading Chancecoin"); 
       /* FXMLLoader fxmloader = new FXMLLoader(); 
       Parent root = fxmloader.load(getClass().getResource("/views/mainFxml.fxml")); 
       MainFxmlController c = (MainFxmlController) fxmloader.getController(); 
       Scene scene = new Scene(root); 
       ////////////////////// 


       Rectangle2D primaryScreenBounds = Screen.getPrimary().getVisualBounds(); 


       stage.getIcons().add(new Image(getClass().getResourceAsStream("/imgs/favIco.png"))); 

       stage.setX(primaryScreenBounds.getMinX()); 
       stage.setY(primaryScreenBounds.getMinY()); 
       stage.setWidth(primaryScreenBounds.getWidth()); 
       stage.setHeight(primaryScreenBounds.getHeight()); 
       stage.setTitle("أستحــقاقــات"); 
       ///////////////////////////////// 



       stage.setScene(scene); 
       stage.show(); 

       */ 
       return null; 
      } 
     }; 

     showSplash(initStage, preloaderTask); 
     new Thread(preloaderTask).start(); 
     showMainStage(); 

    } 

    /** 
    * @param args the command line arguments 
    */ 
    public static void main(String[] args) { 
     launch(args); 
    } 





    private void showMainStage() throws IOException { 
     // create the scene 
     FXMLLoader fxmloader = new FXMLLoader(); 
       Parent root = fxmloader.load(getClass().getResource("/views/mainFxml.fxml")); 
       Scene scene = new Scene(root); 
       ////////////////////// 


       Rectangle2D primaryScreenBounds = Screen.getPrimary().getVisualBounds(); 


       mainStage.getIcons().add(new Image(getClass().getResourceAsStream("/imgs/favIco.png"))); 

       mainStage.setX(primaryScreenBounds.getMinX()); 
       mainStage.setY(primaryScreenBounds.getMinY()); 
       mainStage.setWidth(primaryScreenBounds.getWidth()); 
       mainStage.setHeight(primaryScreenBounds.getHeight()); 
       mainStage.setTitle("أستحــقاقــات"); 
       ///////////////////////////////// 



       mainStage.setScene(scene); 
       mainStage.show(); 

     mainStage.setOnCloseRequest(new EventHandler<WindowEvent>() { 
      @Override 
      public void handle(WindowEvent event) { 
       System.exit(0); 
      } 
     }); 
    } 



    private void showSplash(final Stage initStage, Task task) { 
     progressText.textProperty().bind(task.messageProperty()); 
     loadProgress.progressProperty().bind(task.progressProperty()); 
     task.stateProperty().addListener(new ChangeListener<Worker.State>() { 
      @Override 
      public void changed(ObservableValue<? extends Worker.State> observableValue, Worker.State oldState, Worker.State newState) { 
       if (newState == Worker.State.SUCCEEDED) { 
        loadProgress.progressProperty().unbind(); 
        loadProgress.setProgress(1); 
        mainStage.setIconified(false); 
        initStage.toFront(); 
        FadeTransition fadeSplash = new FadeTransition(Duration.seconds(1.2), splashLayout); 
        fadeSplash.setFromValue(1.0); 
        fadeSplash.setToValue(0.0); 
        fadeSplash.setOnFinished(new EventHandler<ActionEvent>() { 
         @Override 
         public void handle(ActionEvent actionEvent) { 
          initStage.hide(); 
         } 
        }); 
        fadeSplash.play(); 
       } 
      } 
     }); 

     Scene splashScene = new Scene(splashLayout); 
     initStage.initStyle(StageStyle.UNDECORATED); 
     final Rectangle2D bounds = Screen.getPrimary().getBounds(); 
     initStage.setScene(splashScene); 
     initStage.setX(bounds.getMinX() + bounds.getWidth()/2 - SPLASH_WIDTH/2); 
     initStage.setY(bounds.getMinY() + bounds.getHeight()/2 - SPLASH_HEIGHT/2); 
     initStage.show(); 
    } 
} 

Answer 1

我環繞閃屏,,,我犯了一個預加載和它的工作非常適合我這裏是代碼：

/* 
* To change this license header, choose License Headers in Project Properties. 
* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package istehkakat.preloader; 

import javafx.animation.FadeTransition; 
import javafx.application.Preloader; 
import javafx.event.ActionEvent; 
import javafx.event.EventHandler; 
import javafx.scene.Scene; 
import javafx.scene.control.ProgressBar; 
import javafx.scene.image.Image; 
import javafx.scene.image.ImageView; 
import javafx.scene.layout.BorderPane; 
import javafx.scene.layout.BorderPaneBuilder; 
import javafx.scene.paint.Color; 
import javafx.stage.Stage; 
import javafx.stage.StageStyle; 
import javafx.util.Duration; 

/** 
* Simple Preloader Using the ProgressBar Control 
* 
* @author TattoApps 
*/ 
public class Istehkakat_Preloader extends Preloader { 

    private ProgressBar bar; 
    private Stage stage; 
    private boolean isEmbedded = false; 

    public void start(Stage stage) throws Exception { 
     isEmbedded = (stage.getWidth() > 0); 
     this.stage = stage; 
     stage.initStyle(StageStyle.UNDECORATED); 
     stage.initStyle(StageStyle.TRANSPARENT); 
     stage.setScene(createPreloaderScene()); 

     stage.show(); 
    } 

    @Override 
    public void handleProgressNotification(ProgressNotification pn) { 
     bar.setProgress(pn.getProgress()); 
    } 

    @Override 
    public void handleStateChangeNotification(StateChangeNotification evt) { 
     if (evt.getType() == StateChangeNotification.Type.BEFORE_START) { 
      if (isEmbedded && stage.isShowing()) { 
       // fade out, hide stage at the end of animation 
       final FadeTransition ft = new FadeTransition(Duration.seconds(5.2), stage.getScene().getRoot()); 
       ft.setFromValue(1.0); 
       ft.setToValue(0.0); 
       final Stage s = stage; 
       final EventHandler<ActionEvent> eh = new EventHandler<ActionEvent>() { 
        public void handle(ActionEvent t) { 
         s.hide(); 
        } 
       }; 
       ft.setOnFinished(eh); 
       ft.play(); 
      } else { 
       stage.hide(); 
      } 
     } 
    } 

    private Scene createPreloaderScene() { 
     bar = new ProgressBar(); 
     final BorderPane p = BorderPaneBuilder 
       .create() 
       .center(new ImageView(new Image(this.getClass() 
             .getResourceAsStream("/imgs/SplashScreenIll.png")))) 
       .bottom(bar).build(); 
     return new Scene(p, 676, 207, Color.TRANSPARENT); 
    } 
} 

謝謝大家

Answer 2

問題

你必須申報d a MainStage，但從未初始化它。因此，利用它在下面一行是在拋出一個NPE：

mainStage.setIconified(false); 

解決方案

您可以通過初始化mainStage解決這個問題，同時聲明：

private Stage mainStage = new Stage(); 

，或者你可以初始化它在第一次使用它之前showSplash()：

private void showSplash(final Stage initStage, Task task) { 
    ... 
    mainStage = new Stage(); 
    mainStage.setIconified(false); 
    ... 
} 

Answer 3

裏面showMainStage()方法包括此行：

Scene scene = new Scene(root); 
mainStage = new Stage(); // include this 

這將解決您的問題。