I posted this question java-vaadin-14-detect-user-leave-closes-tab-f5-etc but I think I asked the wrong questions.
I want to limit each signed-in user, to just one (1) active browser tab, or UI for that matter.
Someone told me to use
VaadinSession.getCurrent().getUIs(), but this list is incremented by 1 (or 2 if
@Push is enabled) every time the user refreshes the page. This means I can’t check if this list contains more than one (or 2).
I’m lost on this! With native java applications and a built-in login system, I can EASILY limit each user to just one (1) session. It’s harder with a browser. Or maybe it isn’t?
You could maybe register a UI init listener which closes all other UIs in the same session whenever a new UI is initialized?
On the other hand, I would also be curious to understand why you want to prevent users from opening multiple tabs.