[Qgis-developer] Python: how to find all children of a group?

[Marco Bernasocchi]

Hi Andreas, in my multiview plugin there is sth similar, have a look.

ciao
http://hub.qgis.org/projects/multiview/repository/revisions/master/entry/temporalrasterloaderdialog.py



On 11/23/2011 04:29 PM, Andreas Neumann wrote:
> Thanks Barry,
>
> I figured the method "groupLayerRelationship" and saw that it contains a
> list of childLayers.
>
> I am trying to figure it out. It seems a bit complex to use for me. In
> web development I do a lot of tree traversals in the DOM and seems much
> easier to me ...
>
> But I also read that the QgsLegendInterface API grew over time and needs
> some overhauling ...
>
> Thanks for the pointer!
>
> Andreas
>
> On Wed, 23 Nov 2011 15:17:25 +0000, Barry Rowlingson wrote:
>> On Wed, Nov 23, 2011 at 2:53 PM, Andreas Neumann <a.neumann at carto.net>
>> wrote:
>>> Hi,
>>>
>>> I am trying to get a list of layers that are the children of a group
>>> with a
>>> certain group index (or even better by layer name).
>>>
>>> I can't figure out how to do this properly with the QgsLegendInterface
>>> object.
>>>
>>> Does one have a piece of code how to accomplish this?
>>
>> Well all have a piece of code that does that :) Qgis is open source,
>> so we've all got the source...
>>
>> And we have the documentation. I had a look at the qgis api docs:
>>
>> http://www.qgis.org/api/classQgsLegendInterface.html
>>
>> - all the 'children' methods that you maybe tried are Qt things, and
>> so irrelevant and not listed, But that groupLayerRelationship method
>> looks interesting:
>>
>>>>> l.groupLayerRelationship()
>> [[PyQt4.QtCore.QString(u''),
>> [PyQt4.QtCore.QString(u'NER_adm020111123150216751')]],
>> [PyQt4.QtCore.QString(u'group'),
>> [PyQt4.QtCore.QString(u'NER_adm320111123150216816'),
>> PyQt4.QtCore.QString(u'NER_adm220111123150216800'),
>> PyQt4.QtCore.QString(u'NER_adm120111123150216790')]],
>> [PyQt4.QtCore.QString(u'foobar'), []]]
>>
>>
>> Seems to be a nested list of layer names (as QString objects). If you
>> can unravel the output above, it starts with an empty root string,
>> then I've got a layer, a group with three layers, and then and empty
>> layer. You'll soon grok it.
>>
>> So just find the element of the group you are interested in and do a
>> depth-first or breadth first search to whatever depth you want.
>> Simples!
>>
>> Barry
>


-- 
Marco Bernasocchi
www.opengis.ch