Active/Contour activity browsing

[Marco Martin]

Hi all,
let's see what happened recently in the usage of Nepomuk by Plasma Active, 
also building blocks for one of the main user interface pieces for Contour.
(long message but has pictures ;)

a central point is using Activities to organize all our resources, being 
files, contacts or applications, in brief what will be represented by Nepomuk 
resources.

a central piece for wiring up Plasma and Nepomuk is the metadata DataEngine.
here is possible to do arbitrary queries to Nepomuk.

Today i did a little marathon to rework its api, to permit more easily to use 
more than one applet connected to the dataengine and track of the queries that 
can auto update over time.

Now each query is a separate dataengine source and a custom DataContainer for 
each source.
this means a separate QueryServiceClient per query, that can keep track of any 
change.

there is now a new source type, called CurrentActivityResources: (followed by 
the activity id)
this lists all the resources associated with the given activity, and this will 
be used in a view used by default in the center on the Contour activity view.
a service is present too to make possible to add/remove associations between 
activity and resources.

a user interface has been done as well, and here it is how it looks right now:
http://i.imgur.com/GpmUM.png
this is a qml only containment, and uses the common resource delegates 
developed before/during Tokamak. (for different resource types they will 
eventually look in a different way)

it's still rough, (for instance resource types still have the internal user 
unfriendly name, like PaginatedTextDocument) but at this point, modulo some 
bugs i will talk about later, just needs refinements.

what is possible to do with those icons?
a single click opens it, a press and hold opens a menu:
http://i.imgur.com/L8NBx.png

the entries present are just a proof of concept for demo purposes, they just 
show a brief feedback message (they will eventually use the actions provided 
by the share/like/connect service)

one entry that does work is the last: "add to the current activity".
tapping on it it will add that resource to the default view (when no query is 
present)

this entry, in the default view becomes instead "remove from current activity"

It does actually work, however there are still some bugs.
it seems that when a resource is  removed, QueryServiceClient sends 
entriesRemoved() for all of the associated resources, and is necessary to 
reset the query and do it again to get the correct results.
Sebastian, any ideas?

To conclude, a question about the api:
right now the add/remove association is done by a service with those two 
possible operations:
it requires to pass both the nepomuk url of the resources and of the activity 
(means that would even be possible to associate a resource with an activity 
different from the current one, if there will be a ui for it)

a different implementation would be to use kactivityconsumer to figure out the 
current activity and just let add/remove associations to the current *running* 
activity.

Cheers,
Marco Martin