TabView/AccordionPanel: Introduce TabEvent#index

[melloware]

Discussed in https://github.com/orgs/primefaces/discussions/1320

^{Originally posted by DaBe1812 February 28, 2024}
I have a dynamic TabView getting it's content from a List<>.
Opening new tabs works just fine, switching between those tabs updates the ActiveIndex correctly.
Let's pretend I have 6 open tabs, so the last index ist 5. When I close tab no 2 then the last index stays 5 switching the tabs skips TabIndex 1. When I want to clear my List by closing tabs this is a problem becase the indexes in the list differ from the indexes of the tabs.
Is there a way to update the tab indexes or a workaround for this issue?

Workaround from Raptser:

public void onTabClose(TabCloseEvent<?> event) {
      TabView tv = (TabView) event.getComponent();
      int activeIndex = Integer.parseInt(event.getFacesContext().getExternalContext().getRequestParameterMap().get(tv.getClientId() + "_tabindex"));

      FacesMessage msg = new FacesMessage("Closed", "Closed Tab. Active Tab " + activeIndex);
      FacesContext.getCurrentInstance().addMessage(null, msg);
}

[melloware]

it looks like AccordionPanel and TabView share similar code around how it handles this TabClose event so the bug is probably in both.

String tabClientId = params.get(clientId + "_closeTab");
TabCloseEvent closeEvent = new TabCloseEvent(this, behaviorEvent.getBehavior(), findTab(tabClientId));

if (repeating) {
    int tabindex = Integer.parseInt(params.get(clientId + "_tabindex"));
    setIndex(tabindex);
    closeEvent.setData(getIndexData());
    closeEvent.setTab(getDynamicTab());
}

closeEvent.setPhaseId(behaviorEvent.getPhaseId());

super.queueEvent(closeEvent);

if (repeating) {
    setIndex(-1);
}

[jepsar]

Index is not great to indicate a tab when the are dynamic. Using an ID would be better.