Extender tutorial on techbase

[Sebastian Kügler]

Hi Rob,

On Tuesday 09 September 2008 12:00:29 Rob Scheepmaker wrote:
> On Tuesday 09 September 2008 09:14:51 Sebastian Kügler wrote:
> > On Tuesday 09 September 2008 02:26:51 Aaron J. Seigo wrote:
> > > On Monday 08 September 2008, Marco Martin wrote:
> > > > in popupapplet adding the possibility ti replace the icon with a
> > > > generic QGraphicsWidget
>
> I agree, if we make PopupApplet slightly more advanced, libplasmaclock can
> use it, amongst others, and we can cut back massively in duplicate code.
> Because, as Marco suggested, extenders will usually be used inside popups.
> What about adding a virtual function QGW *collapsedWidget() which default
> implementation returns a icon, so default behavior doesn't change, but
> developers can also show custom widgets as needed by the clock and battery
> applet.
>
> > > this probably makes sense. the question would be how to make a nice API
> > > for it.
> > >
> > > there will *still* be cases where this fails and some code will need to
> > > be written, but it's one more case covered at least.
> >
> > The case I've run into is that I'd like to add a popup to a normal applet
> > (in this case the battery). So I'd still want all the magic in
> > paintInterface() to work, and then just add a dialog. That's *mostly*
> > what popupapplet does, but aq couple of things make it unusable for that
> > case: No option to always have it behave like in the panel (i.e. on
> > planar / mediacenter FFs, it always expands. There has been a patch for
> > it, but it wasn't merged, not sure why, but I would use it.
>
> agreed, what about a protected setNeverExpand or something like that (i
> suck at creating good names for functions, but you'll get the idea.

Yes, something like this should do.  There's an implementation for it at
http://reviewboard.vidsolbach.de/r/145/
and corresponding thread on this list with subject:
"Review Request: PopupApplet iconify patch"
I don't follow the logic in there completely, I just noticed that there are a 
couple of cases where this patch would've saved a lot of code (libplasmaclock 
for one), I'd also like to use something like this in the battery applet, but 
had to step away from popupapplet (which actually does the hard work, but 
lacks the flexibility in Allessandro's patch).

> > So can we have something like the normal applet combined with
> > popupdialog? The following methods should be there:
> >
> > - paintInterface() for 'normal applet painting' (not just a
> > graphicswidget) - setHasPopup() and createPopup(Plasma::Dialog dialog)
> > (enables a dialog, much like createConfigurationInterface() in Applet)
>
> I doubt createPopup is needed, we already have widget() and
> graphicsWidget() in which you can decide what your dialog should contain.

Right ...

> > - widget() and graphicsWidget() (to fill the popup with widgets or
> >   plasma::widgets
> >
> > What I would not like to do:
> >
> > - take care of on-demand create of the dialog
> > - take care of positioning the dialog
> >
> > Another problem is that libplasmaclock has a really "interesting"
> > implementation of the extenders. I first took that as an example (in the
> > mid_control applet, but it prove buggy, then I read the tutorial, went
> > "wtf, libplasmaclock is doing something fairly different"). I didn't get
> > the code to work well ... look at mid_control applet if you want to see
> > the details.
>
> Yeah, I focussed on PopupApplet for extenders until now. Take a look at
> kuiserver (playground) for an example of a real world applet that uses
> extenders and isn't very buggy. I was already under the impression that
> libplasmaclock should be using PopupApplet some day.

Ok, will look at that.

> > For the things I'm working on (control panel area with dialogs popping
> > up), the needs are all fairly similar, and sound like something that
> > should be absolutely easy to do. Yet it's not. Modulo my stupidity.
> >
> > That said, I think the API of the extenders (or what I read in the
> > tutorial) is OK, now we need to rule out the bugs :>
>
> Yes, I fixed a lot of bugs there last week, and I'm now at the point where
> I'm very interested in bug reports since there aren't any major and obvious
> bugs left... well in libplasmaclock there are but once that uses
> popupapplet, that should be solved.

Ok, good. I'll harrass you on IRC to get my code working :>
-- 
sebas

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