Re: [Rosegarden-devel] Problem in retrieving value from RG XML Document

[D. M. M. <mic...@ro...>]

On Sunday 27 January 2008, Philippe Macaire wrote:
> I wanted to challenge myself into doing an implementation, feeling
> such a feature would be a good way for a former C++ programmer to know
> better Rosegarden from the inside, and contribute to it.

You can't imagine how much I like the sound of that.  :)

> 1. is this a good place to store this data?

I wouldn't have stored it there, but whoever actually gets into coding 
something first gets a lot of leeway to determine things like this.

It's probably fine.

> 2. since the transport mode is an enum (TimeDisplayMode) it may not be
> robust enough to store the value as an Int, since this value depend on
> its position in the definition of the enum (e.g. BarMode happens to be
> equals to 2 only because it is the third of the list...). Do you think
> it is better to store a string description instead, to be mapped at
> load time to an Int? (e.g. a string "BarMode")

Depending on the position in an enum like that is easy to break down the road, 
so it would be best to avoid that, but probably not a deal breaker I wouldn't 
say.  I'm pretty sure I've done something similarly evil at least once, if 
not more than once, so I probably live in a glass house.

> Now to my actual problem: everything works fine... except that I can't
> manage to load the transportmode value from the file. I modified class
> DocumentConfiguration to store the value into the XML, and this works.
> But when I try to load it (in class RosegardenGUIApp.cpp, just like
> ZoomLevel) I get a NoData exception.
>
> Is there anything to declare somewhere to have the a value loaded from
> the XML file? I tried to delve into class RoseXmlHandler but couldn't
> find anything specific to parameter loading.

My memory of how all of this works is too vague to guess what's going wrong 
without looking at your patch.  I know I managed to do that with the track 
parameters stuff, so I can probably figure out the piece you're missing if I 
can look at it.
-- 
D. Michael McIntyre