modify the drag handler so that it only modifies IE's document.onselectstart while dragging - add jsodc text - all browser event handlers now return a boolean - activate and deactivate respect the return of the parent class and return the same

git-svn-id: http://svn.openlayers.org/trunk/openlayers@2908 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Handler/Drag.js

@@ -16,16 +16,22 @@ OpenLayers.Handler.Drag.prototype = OpenLayers.Class.inherit( OpenLayers.Handler
      * When a mousedown event is received, we want to record it, but not set 
      * 'dragging' until the mouse moves after starting. 
      * 
-     * @type boolean 
+     * @type Boolean 
      **/
     started: false,
     
-    /** @type boolean **/
-    dragging: null,
+    /** @type Boolean **/
+    dragging: false,
 
     /** @type OpenLayers.Pixel **/
     start: null,
 
+    /**
+     * @type Function
+     * @private
+     */
+    oldOnselectstart: null,
+
     /**
      * @constructor
      *
@@ -40,10 +46,16 @@ OpenLayers.Handler.Drag.prototype = OpenLayers.Class.inherit( OpenLayers.Handler
         OpenLayers.Handler.prototype.initialize.apply(this, arguments);
     },
     
+    /**
+     * Handle mousedown events
+     * @param {Event} evt
+     * @type Boolean
+     * @return Should the event propagate
+     */
     mousedown: function (evt) {
         if (this.checkModifiers(evt) && OpenLayers.Event.isLeftClick(evt)) {
             this.started = true;
-            this.dragging = null;
+            this.dragging = false;
             this.start = evt.xy.clone();
             // TBD replace with CSS classes
             this.map.div.style.cursor = "move";
@@ -51,58 +63,113 @@ OpenLayers.Handler.Drag.prototype = OpenLayers.Class.inherit( OpenLayers.Handler
             OpenLayers.Event.stop(evt);
             return false;
         }
+        return true;
     },
 
+    /**
+     * Handle mousemove events
+     * @param {Event} evt
+     * @type Boolean
+     * @return Should the event propagate
+     */
     mousemove: function (evt) {
         if (this.started) {
             this.dragging = true;
             this.callback("move", [evt.xy]);
+            if(document.onselectstart) {
+                if(!this.oldOnselectstart) {
+                    this.oldOnselectstart = document.onselectstart;
+                    document.onselectstart = function() {return false;}
+                }
+            }
         }
+        return true;
     },
 
+    /**
+     * Handle mouseup events
+     * @param {Event} evt
+     * @type Boolean
+     * @return Should the event propagate
+     */
     mouseup: function (evt) {
         if (this.started) {
-            this.started = false; 
+            this.started = false;
+            this.dragging = false;
             // TBD replace with CSS classes
             this.map.div.style.cursor = "default";
             this.callback("up", [evt.xy]);
+            if(document.onselectstart) {
+                document.onselectstart = this.oldOnselectstart;
+            }
         }
+        return true;
     },
 
+    /**
+     * Handle mouseout events
+     * @param {Event} evt
+     * @type Boolean
+     * @return Should the event propagate
+     */
     mouseout: function (evt) {
         if (this.started && OpenLayers.Util.mouseLeft(evt, this.map.div)) {
             this.started = false; 
-            this.dragging = null;
+            this.dragging = false;
             // TBD replace with CSS classes
             this.map.div.style.cursor = "default";
             this.callback("out", []);
+            if(document.onselectstart) {
+                document.onselectstart = this.oldOnselectstart;
+            }
+        }
+        return true;
+    },
+
+    /**
+     * The drag handler captures the click event.  If something else registers
+     * for clicks on the same element, its listener will not be called after a
+     * drag.
+     * @param {Event} evt
+     * @type Boolean
+     * @return Should the event propagate
+     */
+    click: function (evt) {
+        // throw away the first left click event that happens after a mouse up
+        if (OpenLayers.Event.isLeftClick(evt) && this.dragging) {
+            this.dragging = true;
+            return false; 
+        }
+        this.started = false;
+        return true;
+    },
+
+    /**
+     * Activate the handler.
+     * @type Boolean
+     * @return Was activation successful.  Returns false if already active.
+     */
+    activate: function() {
+        if(OpenLayers.Handler.prototype.activate.apply(this, arguments)) {
+            this.dragging = false;
+            return true;
+        } else {
+            return false;
         }
     },
 
     /**
-     * @param {Event} evt
-     * 
+     * Deactivate the handler.
      * @type Boolean
+     * @return Was deactivation successful.  Returns false if not already active.
      */
-    click: function (evt) {
-        // throw away the first left click event that happens after a mouse up
-        if (OpenLayers.Event.isLeftClick(evt) && this.dragging != null) {
-            this.dragging = null;
-            return false; 
+    deactivate: function() {
+        if(OpenLayers.Handler.prototype.deactivate.apply(this, arguments)) {
+            this.dragging = false;
+            return true;
+        } else {
+            return false;
         }
-        this.started = false;
-    },
-
-    activate: function (evt) {
-        OpenLayers.Handler.prototype.activate.apply(this, arguments);
-        document.onselectstart = function() { return false; };
-        this.dragging = null;
-    },
-
-    deactivate: function (evt) {
-        OpenLayers.Handler.prototype.deactivate.apply(this, arguments);
-        document.onselectstart = null;
-        this.dragging = null;
     },
 
     /** @final @type String */