fix for #500 - destroying a layer now has an option to not set a new baselayer. we use this in map.destroy()

git-svn-id: http://svn.openlayers.org/trunk/openlayers@2233 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -137,10 +137,17 @@ OpenLayers.Layer.prototype = {
     /**
      * Destroy is a destructor: this is to alleviate cyclic references which
      * the Javascript garbage cleaner can not take care of on its own.
+     * 
+     * @param {Boolean} setNewBaseLayer Should a new baselayer be selected when
+     *                                  this has been removed?
+     *                                  Default is true
      */
-    destroy: function() {
+    destroy: function(setNewBaseLayer) {
+        if (setNewBaseLayer == null) {
+            setNewBaseLayer = true;
+        }
         if (this.map != null) {
-            this.map.removeLayer(this);
+            this.map.removeLayer(this, setNewBaseLayer);
         }
         this.map = null;
         this.name = null;

lib/OpenLayers/Map.js

@@ -213,7 +213,9 @@ OpenLayers.Map.prototype = {
     destroy:function() {
         if (this.layers != null) {
             for(var i=0; i< this.layers.length; i++) {
-                this.layers[i].destroy();
+                //pass 'false' to destroy so that map wont try to set a new 
+                // baselayer after each baselayer is removed
+                this.layers[i].destroy(false);
             } 
             this.layers = null;
         }
@@ -356,8 +358,13 @@ OpenLayers.Map.prototype = {
      *     its own personal list of popups, removing them from the map.
      * 
      * @param {OpenLayers.Layer} layer
+     * @param {Boolean} setNewBaseLayer Default is true
      */
-    removeLayer: function(layer) {
+    removeLayer: function(layer, setNewBaseLayer) {
+        if (setNewBaseLayer == null) {
+            setNewBaseLayer = true;
+        }
+
         if (layer.isFixed) {
             this.viewPortDiv.removeChild(layer.div);
         } else {
@@ -367,7 +374,7 @@ OpenLayers.Map.prototype = {
         OpenLayers.Util.removeItem(this.layers, layer);
 
         // if we removed the base layer, need to set a new one
-        if (this.baseLayer == layer) {
+        if (setNewBaseLayer && (this.baseLayer == layer)) {
             this.baseLayer = null;
             for(i=0; i < this.layers.length; i++) {
                 var iLayer = this.layers[i];