Detecting when PopupApplet is iconified

[Rob Hasselbaum]

On Fri, Mar 19, 2010 at 1:19 PM, Sebastian Kügler <sebas at kde.org> wrote:
> There are two cases for dataUpdated that matter here, indeed:
> (1) polling / timer-based, for example refreshing RSS feeds
> (2) events, for example from Solid
>
> We want to delay (1) and just keep (2) from propagation until shown. The thing is
> that the dataEngine then would need to know about the Applet's status (is it shown so
> should I update?).

My case falls under #2, but as I said, stopping propagation isn't
sufficient because the work that the data engine has to do to produce
the data is expensive and so I want to avoid it if the data won't be
seen by anybody.

I think you can address both cases, though, by having the applet
disconnect from sources when it's not displayed and reconnect when it
is displayed. Or alternatively, give developers the tools (i.e. an
isDisplayed or similar method) so they can implement that strategy
themselves if they want to. The heuristics of figuring out whether the
applet is visible or not is the only hard part.