Merge pull request #242 from bartvde/layertree

checkedGroup only seems to work with baseLayers

Author: mpriour

src/GeoExt/tree/LayerNode.js

@@ -57,6 +57,7 @@ Ext.define('GeoExt.tree.LayerNode', {
             "visibilitychanged": this.onLayerVisibilityChanged,
             scope: this
         });
+        this.enforceOneVisible();
     },
 
     /**
@@ -109,6 +110,33 @@ Ext.define('GeoExt.tree.LayerNode', {
             }
             delete node._visibilityChanging;
         }
+        this.enforceOneVisible();
+    },
+
+    enforceOneVisible: function() {
+        var attributes = this.target.data;
+        var group = attributes.checkedGroup;
+        // If we are in the baselayer group, the map will take care of
+        // enforcing visibility.
+        if(group && group !== "gx_baselayer") {
+            var layer = this.target.get('layer');
+            var checkedNodes = this.target.getOwnerTree().getChecked();
+            var checkedCount = 0;
+            // enforce "not more than one visible"
+            Ext.each(checkedNodes, function(n){
+                var l = n.data.layer;
+                if(!n.data.hidden && n.data.checkedGroup === group) {
+                    checkedCount++;
+                    if(l != layer && attributes.checked) {
+                        l.setVisibility(false);
+                    }
+                }
+            });
+            // enforce "at least one visible"
+            if(checkedCount === 0 && attributes.checked == false) {
+                layer.setVisibility(true);
+            }
+        }
     }
 
 });