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

[Massimo]

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solution (viewer + plugin) that is obsolete and expensive to maintain that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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