Communication between controllers JavaFX - javafx

Question

I´m trying to display an image on a new windows when I click on a rectangle of my main stage but I receive the following error: "Exception in thread "JavaFX Application Thread" java.lang.NullPointerException"
First controller (ControllerImpl) initializes second controller (ControllerImage) and calls one of its methods (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");
}
});
}
Second controller contains a stack pane and method called by ControllerImpl:
#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));
}
Of course Spi is defined in FXML file:
<StackPane fx:id="Spi"......
Problem is ControllerImage can't find StackPane Spi. I´ve been implementing all kind of solutions I found related to this but no one has worked so far.
Thanks for your help!
EDIT: new error message
javafx.fxml.LoadException: Root value already specified.
/C:/tutorial-app/tutorial-app/target/resources/main/images.fxml
/C:/tutorial-app/tutorial-app/target/resources/main/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

You are creating controllerImage yourself, not through FXMLLoader, so the FXML fields never get injected. You also never call load on that loader. Edit: Oops, you do, I just missed it.
Assuming you have the fx:controller set correctly in "images.fxml", remove the assignment of controllerImage and add this line after the call to FXMLLoader#load:
controllerImage = loader.getController();
If you don't have fx:controller set in the FXML you can either set it to the correct class, or instead pass the instance you create to the loader before loading:
loader.setController(controllerImage);
In this case you would of course keep the initialization of controllerImage.