From 517282baa4b528bc1bb4af64529dc8209e5aa1a7 Mon Sep 17 00:00:00 2001
From: euzuro <euzuro@metacarta.com>
Date: Fri, 7 Jul 2006 14:50:46 +0000
Subject: [PATCH] if gmaps is unable to load, well then we will show the user
 some help

git-svn-id: http://svn.openlayers.org/trunk/openlayers@912 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
---
 lib/OpenLayers/Layer/Google.js | 111 ++++++++++++++++++++++++---------
 1 file changed, 83 insertions(+), 28 deletions(-)

diff --git a/lib/OpenLayers/Layer/Google.js b/lib/OpenLayers/Layer/Google.js
index 065801b00f..f2f4ef0f06 100644
--- a/lib/OpenLayers/Layer/Google.js
+++ b/lib/OpenLayers/Layer/Google.js
@@ -119,40 +119,95 @@ OpenLayers.Layer.Google.prototype = Object.extend( new OpenLayers.Layer(), {
      */
     loadGMap:function() {
         
-        //test if the gmaps library has been loaded
+        //has gmaps library has been loaded?
         var gmapsLoaded = (typeof GMap2) != "undefined";
-        if (gmapsLoaded) {
-         
+        if (!gmapsLoaded) {
+            this.loadWarningMessage();
+        } else {
+
             // create GMap, hide nav controls
             this.gmap = new GMap2(this.div);
-    
-            // this causes the GMap to set itself to Map's center/zoom
-            this.moveTo();
-    
-            // catch pans and zooms from GMap
-            GEvent.addListener(this.gmap, 
-                               "moveend", 
-                               this.catchPanZoom.bindAsEventListener(this)); 
-    
-    
-            // attach to the drag start and end and weŽll set a flag so that
-            //  we dont get recursivity. this is because when we call setCenter(),
-            //  it calls moveTo() on all layers
-            GEvent.addListener(this.gmap, 
-                               "dragstart", 
-                               this.dragStart.bindAsEventListener(this)); 
-    
-            GEvent.addListener(this.gmap, 
-                               "dragend", 
-                               this.dragEnd.bindAsEventListener(this)); 
-    
-            // catch pans and zooms from GMap
-            GEvent.addListener(this.gmap, 
-                               "drag", 
-                               this.catchPanZoom.bindAsEventListener(this)); 
+
+            if (this.gmap == null) {
+                this.loadWarningMessage();
+            } else {
+        
+                // this causes the GMap to set itself to Map's center/zoom
+                this.moveTo();
+        
+                // catch pans and zooms from GMap
+                GEvent.addListener(this.gmap, 
+                                   "moveend", 
+                                   this.catchPanZoom.bindAsEventListener(this)); 
+        
+        
+                // attach to the drag start and end and weŽll set a flag so that
+                //  we dont get recursivity. this is because when we call setCenter(),
+                //  it calls moveTo() on all layers
+                GEvent.addListener(this.gmap, 
+                                   "dragstart", 
+                                   this.dragStart.bindAsEventListener(this)); 
+        
+                GEvent.addListener(this.gmap, 
+                                   "dragend", 
+                                   this.dragEnd.bindAsEventListener(this)); 
+        
+                // catch pans and zooms from GMap
+                GEvent.addListener(this.gmap, 
+                                   "drag", 
+                                   this.catchPanZoom.bindAsEventListener(this)); 
+            }
         }
     },
 
+    /** If we can't load the GMap, then display an error message to the 
+     *   user and tell them where to go for help.
+     */
+    loadWarningMessage:function() {
+
+        this.div.style.backgroundColor = "red";
+
+        var html = "";
+        html += "The Google Layer was unable to load correctly.<br>";
+        html += "<br>";
+        html += "Most likely, this is because the Google Maps library";
+        html += " script was either not included, or does not contain the";
+        html += " correct API key for your site.<br>";
+        html += "<br>";
+        html += "If you wish to use a GMaps Layer with OpenLayers, you";
+        html += " must include the gmaps script library in your HTML";
+        html += " file, just before including OpenLayers.js.<br>";
+        html += "<br>";
+        html += "For help getting this working correctly, ";
+        html += "<a href='http://trac.openlayers.org/wiki/Google' "
+        html +=  "target='_blank'>";
+        html +=     "click here";
+        html += "</a>";
+        
+        var viewSize = this.map.getSize();
+        
+        msgW = Math.min(viewSize.w, 300);
+        msgH = Math.min(viewSize.h, 200);
+        var size = new OpenLayers.Size(msgW, msgH);
+
+        var centerPx = new OpenLayers.Pixel(viewSize.w/2, viewSize.h/2);
+
+        var topLeft = centerPx.add(-size.w/2, -size.h/2);            
+
+        var div = OpenLayers.Util.createDiv("gmapsWarning", 
+                                            topLeft, 
+                                            size,
+                                            null,
+                                            null,
+                                            null,
+                                            "auto");
+
+        div.style.backgroundColor = "yellow";
+
+        div.innerHTML = html;
+        this.div.appendChild(div);
+    },
+
     /** 
      * @private
      */