In GWTP how can TabLayoutPanel events be handled?

Question

I've followed Dani's GWTP Course but using TabLayoutPanel with presenters isn't covered.

I have a TabLayoutPanel with 3 tabs (each with a VerticalPanel on it). I've used @ProxyCodeSplit so that the code for each tab is loaded independently.

If in Eclipse, in GWT's Designer I add a handler for OnBeforeSelection then code is auto-added into my View. The View can then load up the appropriate presenter.

That doesn't feel like the right place for the code - but is it?

How are you handing different tabs within TabLayoutPanel and code splitting?

Answer 1

I think I've got this figured out.

In your presenter with the TabLayoutPanel (let's call it MainPresenter):

@ContentSlot public static final Type<RevealContentHandler<?>> SLOT_first = new Type<RevealContentHandler<?>>();
@ContentSlot public static final Type<RevealContentHandler<?>> SLOT_second = new Type<RevealContentHandler<?>>();

public interface MyView extends View {
    public void setMainPresenter(MainPresenter presenter);
    public TabLayoutPanel getTeamsPanel();
}

@Inject PlaceManager placeMananger;
@Inject FirstPresenter firstPresenter;
@Inject SecondPresenter secondPresenter;

@ProxyCodeSplit
public interface MyProxy extends Proxy<MainPresenter> {
}

@Inject
public MainPresenter(final EventBus eventBus, final MyView view,
        final MyProxy proxy) {
    super(eventBus, view, proxy);
    view.setMainPresenter(this);
}

@Override
protected void revealInParent() {
    RevealRootContentEvent.fire(this, this);
}

public void setTabContents(Integer tab) {
    if (tab == 0) {
        placeMananger.revealPlace(new PlaceRequest("first"));
    } else if (tab == 1) {
        placeMananger.revealPlace(new PlaceRequest("second"));
}

Then in your MainView implement the method setMainPresenter() to store a reference locally. Implement the usual setInSlot() and then add this tab handler:

@UiHandler("mainTabs")
void onMainTabsBeforeSelection(BeforeSelectionEvent<Integer> event) {
    mainPresenter.setTabContents(event.getItem());
}

The handler will call MainPresenter each time the user changes tabs. setTabContents() will then call revealInParent() for the appropriate "tab" Presenter.