Due to circular references, the layer switcher could prevent layers from

being cleared in Internet Explorer. This patch fixes #577. Patch from Erik.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@2918 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/LayerSwitcher.js

@@ -25,7 +25,7 @@ OpenLayers.Control.LayerSwitcher.prototype =
     baseLayersDiv: null,
 
     /** @type Array */
-    baseLayerInputs: null,
+    baseLayers: null,
     
     
     /** @type DOMElement */
@@ -35,7 +35,7 @@ OpenLayers.Control.LayerSwitcher.prototype =
     dataLayersDiv: null,
 
     /** @type Array */
-    dataLayerInputs: null,
+    dataLayers: null,
 
 
     /** @type DOMElement */
@@ -85,6 +85,27 @@ OpenLayers.Control.LayerSwitcher.prototype =
         return this.div;
     },
 
+    /** user specifies either "base" or "data". we then clear all the 
+     *    corresponding listeners, the div, and reinitialize a new array.
+     * 
+     * @private
+     * 
+     * @param {String} layersType Ei
+     */
+    clearLayersArray: function(layersType) {
+        var layers = this[layersType + "Layers"];
+        if (layers) {
+            for(var i=0; i < layers.length; i++) {
+                var layer = layers[i];
+                OpenLayers.Event.stopObservingElement(layer.inputElem);
+                OpenLayers.Event.stopObservingElement(layer.labelSpan);
+            }
+        }
+        this[layersType + "LayersDiv"].innerHTML = "";
+        this[layersType + "Layers"] = new Array();
+    },
+
+
     /** Goes through and takes the current state of the Map and rebuilds the
      *   control to display that state. Groups base layers into a radio-button
      *   group and lists each data layer with a checkbox.
@@ -95,11 +116,8 @@ OpenLayers.Control.LayerSwitcher.prototype =
     redraw: function() {
 
         //clear out previous layers 
-        this.baseLayersDiv.innerHTML = "";
+        this.clearLayersArray("base");
-        this.baseLayerInputs = new Array();
+        this.clearLayersArray("data");
-        
-        this.dataLayersDiv.innerHTML = "";
-        this.dataLayerInputs = new Array();
         
         var containsOverlays = false;
         
@@ -128,14 +146,17 @@ OpenLayers.Control.LayerSwitcher.prototype =
                 inputElem.value = layer.name;
                 inputElem.checked = checked;
                 inputElem.defaultChecked = checked;
-                inputElem.layer = layer;
-                inputElem.control = this;
 
                 if (!baseLayer && !layer.inRange) {
                     inputElem.disabled = true;
                 }
+                var context = {
+                    'inputElem': inputElem,
+                    'layer': layer,
+                    'layerSwitcher': this
+                }
                 OpenLayers.Event.observe(inputElem, "mouseup", 
-                              this.onInputClick.bindAsEventListener(inputElem));
+                              this.onInputClick.bindAsEventListener(context));
                 
                 // create span
                 var labelSpan = document.createElement("span");
@@ -143,16 +164,21 @@ OpenLayers.Control.LayerSwitcher.prototype =
                     labelSpan.style.color = "gray";
                 }
                 labelSpan.innerHTML = layer.name;
-                labelSpan.style.verticalAlign = (baseLayer) ? "bottom" : "baseline";
+                labelSpan.style.verticalAlign = (baseLayer) ? "bottom" 
+                                                            : "baseline";
                 OpenLayers.Event.observe(labelSpan, "click", 
-                              this.onInputClick.bindAsEventListener(inputElem));
+                              this.onInputClick.bindAsEventListener(context));
                 // create line break
                 var br = document.createElement("br");
     
                 
-                var groupArray = (baseLayer) ? this.baseLayerInputs
+                var groupArray = (baseLayer) ? this.baseLayers
-                                             : this.dataLayerInputs;
+                                             : this.dataLayers;
-                groupArray.push(inputElem);
+                groupArray.push({
+                    'layer': layer,
+                    'inputElem': inputElem,
+                    'labelSpan': labelSpan
+                });
                                                      
     
                 var groupDiv = (baseLayer) ? this.baseLayersDiv
@@ -173,18 +199,24 @@ OpenLayers.Control.LayerSwitcher.prototype =
      * 
      * @private
      * 
+     * @context 
+     *      {DOMElement} inputElem
+     *      {OpenLayers.Control.LayerSwitcher} layerSwitcher
+     *      {OpenLayers.Layer} layer
+     * 
      * @param {Event} e
      */
 
     onInputClick: function(e) {
-        if (!this.disabled) {
+
-            if (this.type == "radio") {
+        if (!this.inputElem.disabled) {
-                this.checked = true;
+            if (this.inputElem.type == "radio") {
+                this.inputElem.checked = true;
                 this.layer.map.setBaseLayer(this.layer, true);
                 this.layer.map.events.triggerEvent("changebaselayer");
             } else {
-                this.checked = !this.checked;
+                this.inputElem.checked = !this.inputElem.checked;
-                this.control.updateMap();
+                this.layerSwitcher.updateMap();
             }
         }
         OpenLayers.Event.stop(e);
@@ -211,17 +243,17 @@ OpenLayers.Control.LayerSwitcher.prototype =
     updateMap: function() {
 
         // set the newly selected base layer        
-        for(var i=0; i < this.baseLayerInputs.length; i++) {
+        for(var i=0; i < this.baseLayers.length; i++) {
-            var input = this.baseLayerInputs[i];   
+            var layerEntry = this.baseLayers[i];
-            if (input.checked) {
+            if (layerEntry.inputElem.checked) {
-                this.map.setBaseLayer(input.layer, false);
+                this.map.setBaseLayer(layerEntry.layer, false);
             }
         }
 
         // set the correct visibilities for the overlays
-        for(var i=0; i < this.dataLayerInputs.length; i++) {
+        for(var i=0; i < this.dataLayers.length; i++) {
-            var input = this.dataLayerInputs[i];   
+            var layerEntry = this.dataLayers[i];   
-            input.layer.setVisibility(input.checked, true);
+            layerEntry.layer.setVisibility(layerEntry.inputElem.checked, true);
         }
 
     },