[maemo-developers] New apps for fremantle with Qt?

[From: Graham Cobb]

On Friday 04 September 2009 18:16:43 kate.alhola at nokia.com wrote:
> To avoid re-inventing the wheel again we are providing examples how
> you can do things with Qt. If some thing can be done with dozen lines of
> Qt code, it just matter of taste, should we provide widget or just
> example that you can cut-and-paste. The most important thing is that
> we have all basic widgets like finger scrollable lists etc so that
> only action needed is to collect them together.

It is absolutely NOT a matter of taste!  Widgets and examples achieve 
completely different goals.  Examples are good if different applications are 
expected to work differently (e.g. examples are good for showing how to open 
a browser window or read a file).  Widgets are necessary if different 
applications are expected to look the same.

Widgets are not provided just to reduce the amount of coding the application 
has to do but to provide a single place to change in order to change the look 
of all applications, without needing to change the application (or even 
recompile it)!

When porting my applications to Fremantle I have not had to add #ifdef's for 
all my dialog boxes to cause them to have buttons on the right.  Why is that?  
it is because I used a dialog box widget and the widget has been modified to 
do that! And maybe some future device will decide the dialog box buttons will 
need to go at the bottom again (maybe it is portrait oriented, or the fashion 
changes) -- exactly the same binary will work on that platform and the 
buttons will be at the bottom.

Widgets are extremely important for composites.  As important as they are for 
basics.  The more widgets you provide the better the standardisation of the 
application UI -- no composite widget can be replaced with an example without 
losing that standardisation at some time in the future when the look needs to 
change.

Note that this doesn't mean that the set of widgets for Qt necessarily needs 
to be the same as for Hildon.  Composite widgets are a simple tradeoff of 
development time against UI standardisation and the Harmatten team may decide 
to make that tradeoff differently and choose to implement a different set of 
widgets.  And in different toolkits, different amounts of the required 
behaviours may be built into some of the underlying widgets directly so there 
are apparently fewer widgets (but, in fact, the widget behaviour is still 
there).  But we need to remember that each time we choose not to implement 
some behaviour in the toolkit, but leave it as an example for the 
application, application behaviour for that function will no longer be 
standardised.

Graham