Restoring weather applet in kdeplasma-addons

[Friedrich W. H. Kossebau]

Am Freitag, 5. Februar 2016, 19:15:29 CET schrieb Marco Martin:
> On Friday 05 February 2016 18:39:00 Friedrich W. H. Kossebau wrote:
> > I see. And found it now, plasma-workspace/dataengines/weather. Seems 
it
> > was started in 2014, but then lost focus of developers. Some "ions"
> > library is installed, but the dataengine plugin itself is not even 
build.
> > 
> > Will look some more around and see where the loose ends to pick up 
are.
> 
> i'm finishing the port right now, seems easier then expected :)

Oh, good, always best to have the expert do things. ;)

Can confirm the code in master works here as well.

> so yeah, you would have to take the qml1 weather applet, port to qml2
> (wouldn't do anything at that point) then hook it up to the dataengine 
and
> give it a configuration dialog.
> I can walk you trough the steps

Being new to both Plasma5 (applet) technologies (only did minor C++ 
plasmoids for Plasma4) as well as the weather applet(s) code and logic, I 
tried to learn a little for now by looking into porting the current code 
and its structure.

So QQ1->QQ2, kdelibs4->KF5 and Plasma->Plasma5, the latter learning-by-
doing and not all changes yet understood.

And I did to some first rough success, the weather applet shows up when 
testing with plasmawindowed, and using a hardcoded data source string 
(using Turin :) ) I get correct weather data shown in the applet.
No config support yet, are QWidget-based config dialogs that even still 
supported API-wise?

For a start I would not mind first recreating the the QWidget-based 
config, so there is a stable working intermediate state, and I have a 
clear picture about the data flows and logic, before going the 

IIRC the ideal Plasma5 applet is qml-only, right? Not sure yet if all 
current logic would best or could be moved to qml/js.
That libplasmaweather, as shared between the applets weather and 
weatherstation (no idea about this, never used), has functionality like 
at least:
* WeatherValidator, for correct input of weather data provider and 
correct input of weather locations supported by the provider
* integration with KNewStuff for weather data providers
 (though currently bound to private and no longer existing
http://www.sh0n.net/spstarr/khotnewstuff/plasmaweather-providers.xml)
* KUnitConversion data handling config & widgets, no idea yet how to port 
that to QQ2
* further data processing of the raw data delivered by the weather data 
engines and feeding of view models

Perhaps some things should be moved to QmlExtension rather?
Would not mind completing the recreation of the weather applet to a 
perfect implementation of how things should be done. So happy to be 
walked through the steps. But at the same time I need after every step a 
milestone where things work completely :)

Pushed as branch kossebau/weatherapplet to kdeplasma-addons, so you can 
have a look, feedback welcome.

Not sure if there is an issue with PlasmaComponents.TabGroup:
in main.qml I currently need to disable setting the "model" property of 
the "DetailsView" item:
//             model: plasmoid.nativeInterface.detailsModel
otherwise the tab bar is not shown.
Any idea why that can happen?

Cheers
Friedrich