[Users] layer tree configuration question

[Ralph Dell]

Matt, Thank you for the detailed answer. It will be looking at it, with
some wrinkling of the brow, next week, and will post my results.

 

Ralph Dell, GISP

GIS Dept.

Catawba County, NC

 

From: Matt Priour [mailto:mpriour at kestrelcomputer.com] 
Sent: Friday, March 26, 2010 3:29 PM
To: Ralph Dell; users at geoext.org
Subject: Re: [Users] layer tree configuration question

 

I can tell you from a lot of trial & error, that the 'children' property
of any gx_layerXXX nodetype are not evaluated. BaselayerContainer,
OverlaylayerContainer, ParamLayer all use loaders to populate their
child node arrays. The best you can do with either of these 3 node types
is to set a 'baseParams' property which will need get applied as part of
the node config for each of the child nodes created by the loader.

 

If you use gx_layer as the nodetype, then the childnodes do get
evaluated. However, it also expects to find a layer property on the node
and a matching layer in the layer store. If either of these conditions
aren't met, errors will occur and your tree won't render or work
correctly.

 

You have a few options:

1. Be highly specific for the layer nodes you want to customize. Use
'async' & 'gx_layer' node types with the specific layer & attributes you
wish to represent. You can use a 'gx_layer' node type as a group layer
container node, but it must also have a matching layer in the layer
store (I've never tried a dummy layer here but it might also work).

 

2. Use the 'gx_layerparam' or 'gx_overlaylayercontainer' node to create
the tree and then modify the node ui after creation. In other words,
write a function to find the layer you are interested in, access the
associated node, access the node's nodeUI and change properties there
(such as the iconCls, etc...)

 

3. I have created a custom node type (gx_complexlayer) that has similar
node construction logic as the 'gx_layer' node type but doesn't expect a
layer property and expects it's descendant nodes (at some level) to have
a layer property. This was useful to me as it can contain both gx_layer
nodes and other loader based nodes as well as using a loader itself if
configured to do so. I've made a ticket for this functionality but not
submitted a patch yet, because I 'haven't written test or an example for
this node type yet and it will fail in some corner cases. I have
attached it as a patch here if you want to use it with the understanding
that it is certainly incomplete.

 

Matt Priour

Kestrel Computer Consulting

 

From: Ralph Dell <mailto:RDell at CatawbaCountyNC.gov>  

Sent: Friday, March 26, 2010 1:32 PM

To: users at geoext.org 

Subject: [Users] layer tree configuration question

 

Thanks to the examples and previous forum posts I almost have my layer
tree looking exactly as I would like.

 

What I haven't been able to figure out is under  a layer check box, (in
this case Schools), I would like to display icons and text that would
correspond to  map symbology for different types of features in the
given layer.  I do not get anything displayed under the check box and
have been unsuccessful  in finding a solution.

 Any pointers or examples on how to accomplish that would be
appreciated.

 

I am pulling my layers from a group layer similar to Tasmania ( Group
Layer) in the Tree Nodes example.

 

Here is my json:

 

var treeConfig = new OpenLayers.Format.JSON().write([

  {

   nodeType: "gx_baselayercontainer",

  layer: 'Layers',

  isLeaf : false,

 loader: {

       param: "LAYERS"

  }

  },{

  text: 'School Layers',

  expanded: true,

  children: [{

   nodeType: "gx_layerparam",

   layer: 'Schools',

  param: "LAYERS",

  item: "catawba2:schools",

  text: 'Schools',

  expanded: true,

  children: [{                                                        //
under the Schools check box I want to display symbols and text that
correspond

     text: 'Elementary Schools',                     // to the symbology
that I use on the map

    IconCls: 'cc_elem'                                        // nothing
displays

    },{
// how can I add symbols and text here?

    text: 'Middle School Districts3',              // I don't even know
if using children: [{}] is the correct approach.

    iconCls: 'cc_middle'

     }]

},{

nodeType: "gx_layerparam",

layer: 'Schools',

param: "LAYERS",

item: "catawba2:elementary_school_districts",

text: 'Elementary School Districts',

iconCls: 'cc_elem_line',

}]

 }], true);

 

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