[maemo-developers] [maemo-developers] Switching between appviews ...

[From: Kalle Vahlman]

On 7/2/05, Jorge Souza <sao_jorge31 at yahoo.com.br> wrote:
> > The switching needs no widget juggling, the only
> > thing that is
> > actually reparented is  the appviews, but that's an
> > implementation
> > detail.
> Ok. I tried this approach because I've saw apps using
> it as well. Again, in my case I am able to change the
> widgets between my appview, but the added ones do not
> appear after remove the first ones.

It seems that the Appview (at least in the current public version)
indeed has some buggy behaviour as a container, I encountered some
wierd assertion failures.

This however works:

  gtk_container_remove (GTK_CONTAINER (appview), GTK_BIN (appview)->child);

so it seems the lookup code is somehow screwed or something like that.

[snip]
> I got it. Thanks. But what I had in mind was using
> just one appview aiming to save so memory as I can (in
> fact, I don't know if it is a significant save :S -
> probably NO, since the users won't to open many
> "windows" of the same app in a embedded device. Am I
> right ?!)

I don't see how you'd manage to have only one AppView but two buttons
in the task navigator? Unless you can register the same AppView twice
(which should be a bug, not a feature ;).

For the memory part, I don't know exactly how much of an overhead it
introduces but I'd guess it's nowhere near to justify the amount of
hacky-wacky you need to do for it to work properly.

What comes to the menu part, it is more useful to have a menu for each
view instead of one for all, although it has the synchronation
drawback. Though it should be noted that global items need to have
only the item multiple times, the callback activated can of course be
the same for all global items of the same type.

This is basically because if you'd have just one menu, you'd have to
add any menuitem relevant to your app to the menu, even if it wouldn't
have anything to do with the currently visible appview and widgets.
That would be bad usability-wise and also would eat screenspace (which
is not abundant to begin with).

Unless you'd be into hacky-wacky and alter the menu every time the
appview is switched (which sounds like more work for the poor CPU and
the coder than an enhancement of anything).

Everything is a selection between memory consumption and CPU usage
(which usually also means more burden to the coder). For low-end
machine like this I'd go for memory in this kind of small-hit issues
(let's face it, there won't be over five apps running on these
machines regularly). Plus since the 770 has some
backgroung-program-magic, it really is not worth it IMO to start doing
anything too hacky.

-- 
Kalle Vahlman, zuh at iki.fi