控制器之間的通信JavaFX

Question

我試圖在我的主要舞臺的矩形上單擊時顯示在新窗口上的圖像，但我收到以下錯誤：「線程中的異常」JavaFX Application Thread「java.lang.NullPointerException 「

第一控制器（ControllerImpl）初始化第二控制器（ControllerImage），並調用它的方法（controllerImage.displayImageSel）：

@FXML 
private ControllerImage controllerImage = new ControllerImage(); 
public void rectangleSave(Rectangle r, String imagePath) { 
    r.setOnMousePressed((event) -> { 
     try { 
      Stage imageStage = new Stage(); 
      FXMLLoader loader = new FXMLLoader(getClass().getResource("/images.fxml")); 

      Rectangle2D primScreenBounds = Screen.getPrimary().getVisualBounds(); 
      imageStage.setX(0); 
      imageStage.setY(0); 
      imageStage.setHeight(primScreenBounds.getHeight()); 
      imageStage.setWidth(primScreenBounds.getWidth() * 0.7); 
      imageStage.setTitle("JavaFX Scene Graph Demo"); 

      Scene scene = new Scene(loader.load()); 
      imageStage.setScene(scene); 
      imageStage.show(); 

      controllerImage.displayImageSel(imagePath); 

     } catch (IOException e) { 
      System.out.println("Me cago en el PP"); 
     } 
    }); 
} 

第二控制器包含由ControllerImpl稱爲堆棧窗格和方法：

@FXML 
public StackPane Spi; 
public void displayImageSel(String imagePath) { 
    Rectangle ri = new Rectangle(); 
    Spi.getChildren().add(ri); 
    Image image = new Image(new File(imagePath).toURI().toString()); 
    ri.setFill(new ImagePattern(image)); 
} 

當然SPI處於FXML文件中定義：

 <StackPane fx:id="Spi"...... 

問題是ControllerImage找不到StackPane靈寶。我一直在實施我發現的與此有關的所有解決方案，但目前爲止還沒有人工作。

感謝您的幫助！

編輯：新的錯誤消息

javafx.fxml.LoadException: Root value already specified. 

/C:/tutorial-app/tutorial-app/target/resources/main/images.fxml /C：/教程應用內/教程應用內/目標/資源/主/ images.fxml

at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2597) 
at javafx.fxml.FXMLLoader.createElement(FXMLLoader.java:2755) 
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2704) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527) 
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441) 
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409) 
at tutorial.controller.impl.ControllerImpl.lambda$rectangleSave$1(ControllerImpl.java:146) 
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86) 
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) 
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) 
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) 
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) 
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) 
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54) 
at javafx.event.Event.fireEvent(Event.java:198) 
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757) 
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$MouseEventNotification.run(GlassViewEventHandler.java:352) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275) 
at java.security.AccessController.doPrivileged(Native Method) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:388) 
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:387) 
at com.sun.glass.ui.View.handleMouseEvent(View.java:555) 
at com.sun.glass.ui.View.notifyMouse(View.java:937) 
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191) 
at java.lang.Thread.run(Thread.java:745) 

Answer 1

你正在創建controllerImage自己，而不是通過FXMLLoader，所以FXML領域永遠不會注入。 您也永遠不會在該裝載程序上調用load。編輯：糟糕，你呢，我只是錯過了它。

假設你有fx:controller在「images.fxml」正確設置，刪除的controllerImage分配和調用後添加此行FXMLLoader#load：

controllerImage = loader.getController(); 

如果你沒有在fx:controller集FXML你可以將其設置爲正確的類，或代替以前裝載傳給你創建的裝載機實例：

loader.setController(controllerImage); 

在這種情況下，你當然會保持controllerImage的初始化。