A quote I picked up on twitter the other day which I really liked and seems very appropriate here:

-Mary Poppendieck

I was going to point out, again, that it's perfectly possible for two very different looking platforms, even with different interaction models to have a common core API. The reason being because you're not innovating so radically in UX that we no longer have basic concepts like lists and buttons - even if Harmattan does make a giant leap forward. However, it seems plenty of others are on the same page and have beaten me to it.

Considering Hildon's first incarnation as yet another UI framework for Symbian (Series 90) that no-one wanted to write apps specifically for, you'd have thought Nokia might have learned this lesson by now.

I know that the Qt folks are going to do everything they can to make things look good. However, if you're using fundamentally different building blocks the end result isn't going to be satisfactory - yes that's a prediction but it's one I'm fairly confident about.

No, this is an important distinction, we are discussing UI framework APIs here, nothing to do with how the things will actually look and everything to do with how much effort is involved in targetting multiple platforms.

We have one example here clearly spelled out in this thread. Qt 4.6 is missing any standard QGraphicsWidgets. If we want to build animated UIs we need some. If we want to build cross-platform animated UIs we need a common interface to them across platforms.

Developers can of course build their own QGraphicsWidget set in pure Qt. It's a lot of work. However, if their apps want to integrate well into Maemo and Symbian then they may well want to integrate with the theme engine - which is presumably separate again on each platform (I'd love someone to come and tell me otherwise, since we are surely in the realms of pure Qt here). Suddenly it's becoming a massive amount of work.

Being able to use custom QGraphicsItems and QGraphicsWidgets in the Maemo containers doesn't help at all (well you could possibly port Symbian ones to Maemo or vice versa - but that's not going to give the platform look and feel).

Of course it's all built with Qt, so it does mean you can have a lot more code reuse than you got historically, but we're still a very long way short of the cross-platform promise.

Mark