[Qgis-developer] index in self.legend.groupLayerRelationship - different behavior between QGIS 1.8 and master?

[kimaidou]

Hi all,

In Lizmap plugin, I need to display the layer and group tree. You can find
some code here :
https://bitbucket.org/mdouchin/lizmapplugin/src/9cdfa856b8f0/lizmap.py
Line 451 : populateLayerTree

There is some specific lizmap code in there, but you can probably use some
of it.

Michael

2012/10/4 Massimo <massimo.endrighi at geopartner.it>

> Hi,
>
>
> Andreas Neumann wrote
> > 1. the method providing access to layers by name could return a list /
> > array with layer references - if the plugin author knows/assumes that
> > the layer names in his project are distinct he can just pick up the
> > first reference in the list
>
> Layer or groups ?
> Finding a layer in the legend is always possible even if there are another
> layer with the same name using legend.layers() that returns QList<
> QgsMapLayer * >  and then is up to you to distinguish the layer.
>
>
> Andreas Neumann wrote
> > The current way to access the legend tree is complicated and not
> > developer friendly - ....
>
> Programmatically move a layer to a specified groups is not a common
> scenario
> but if you have to do that and you have nested groups there should be a way
> to uniquely index a group.
> Programmatically traversing the legend tree and keep track of its parent
> group is not a common scenario too and groupLayerRelationship can not help
> when there are groups with the same name.
>
>
> Andreas Neumann wrote
> >  ....- and currently it is buggy (returns the wrong index).
>
> I don't want to be annoying but please consider the following simple legend
> example:
>
> - Layer1
> - Group1
> - Group2
> --- NestedGroup3
> - Group4
>
> Suppose you want to use your test to move Layer1 in NestedGroup3
> Your test code will fail and any other test will fail because
> self.legend.moveLayer in QGis 1.7 and 1.8 considers only top level group.
>
> I've introduced a different group indexing in 1.9 that is consistent with
> legend.groups() indexing.
> Now the same legend tree is indexed in the following manner:
> - Layer1
> - Group1   [groupIndex=0]
> - Group2   [groupIndex=1]
> --- NestedGroup3    [groupIndex=2]
> - Group4   [groupIndex=3]
>
> that is consistent with the list returned by legend.groups() and give a
> consistent meaning to the groupIndex parameter used in the API
> documentation.
>
> I'm sorry for this drawback and I'm ready to contribute to a common
> solution
> that accommodates all the needs.
>
> In my case I need to :
> - load a third-party "workspace" file with a tree of groups and layers.
> - write a third-party "workspace" file with a tree of groups and layers
> starting from a qgis legend
>
> The main goal of the plugin I'm writing is to substitute a commercial
> solution (viewer + plugin) that is obsolete and expensive to maintain that
> is actually used by an Italian public administration.
>
> Massimo
>
>
>
>
>
>
> --
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> http://osgeo-org.1560.n6.nabble.com/index-in-self-legend-groupLayerRelationship-different-behavior-between-QGIS-1-8-and-master-tp5004337p5006367.html
> Sent from the Quantum GIS - Developer mailing list archive at Nabble.com.
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