CDI Event binding

Vaadin 6 / 7 / 8
1

Hi,
i’am new to vaadin and i use vaadin with the cdi extention. I created a View with some Input elements.
On buttonclick i open a subwindow where the user can select some things. This things need to be transfered to the forms of the view. I want to transport the selection via an event back to the view. But the Observer Method never gets called.
This Feature is essential for my application because i want to decouple the window from the view to use the window on many places inside this and other applications.

Here is some code of what i try to do.

MainView

[code]
@CDIView(“search”)
@UIScoped
public class Search extends VerticalLayout implements View{

private TextField test;
private Button testButton;

//… layout stuff and add window in button clicklistener

public void listenToSelection(@Observes(notifyObserver = Reception.IF_EXISTS) SelectionEvent event){
test.setValue(event.getValue());
}
}
[/code]SearchWindow

@UIScoped
public class SearchWindow extends Window{

@Inject
javax.enterprise.event.Event<SelectionEvent> selectEvent;

//call selectEvent.fire(event); somewhere

}

The listenToSelection Method never gets called. Any idea how to fix this problem? Has it something to do with the different Scopes of the View and the Window?

2

Hi,

Try removing the
@UIScoped
 annotation in your
Search
 class (the view implementation). With this change, the view won’t retain its state when the user navigates to another view (it will have view scope).

3

Hi,
jep this works. But i have to retain the view state (it is a customer request). Is there any other way?

4

I tested it and it works in views with
@UIScoped
 when the observer method is not conditional (without
notifyObserver = Reception.IF_EXISTS
 or with
notifyObserver = Reception.ALWAYS
). So, the problem might be related to scopes.

5

Hi,
thank you for the reply and sorry for the long delay. I was out for holiday :wink:

To the problem. I added
notifyObserver = Reception.ALWAYS
to my observer and you are right, the view observer gets the event. But in the wrong instance of the view. It seems like it creates a new instance of the view and sets the values.

I have a second window in the same view with the same task to let the user select some things and transfer it on button click to the main view. ​Interestingly those windows seem to share the same Instance of the view but not on the “right” instance.

Any ideas how to get it in the “right” view?

6

I’d avoid coupling the UI with my data and use a SessingScoped bean for passing data back and forth. My two cents. I personally like to keep the view layer as decoupled as possible