Save and display data on form submission

app/views/rails_admin/main/_form_map.html.haml

@@ -1,16 +1,48 @@
 = javascript_include_tag ("http://maps.googleapis.com/maps/api/js?key=#{field.google_api_key}&sensor=false")
 = #require_asset('ramf.js')
 
-:javascript
-  jQuery(function(){
-    var latlng = new google.maps.LatLng( #{form.object.send(field.name) || field.default_latitude}, #{form.object.send(field.name) || field.default_longitude});
-    var myOptions = {
-      zoom: 8,
-      center: latlng,
-      mapTypeId: google.maps.MapTypeId.ROADMAP
-    };
-    var map = new google.maps.Map(document.getElementById("#{field.dom_name}"), myOptions);
-  });
+= javascript_tag do
+  :plain
+    jQuery(function(){
+      var marker = null;
+      var latlng = new google.maps.LatLng(#{form.object.send(field.name) || field.default_latitude}, #{form.object.send(field.longitude_field) || field.default_longitude});
+
+      var myOptions = {
+        zoom: 8,
+        center: latlng,
+        mapTypeId: google.maps.MapTypeId.ROADMAP
+      };
+
+      var map = new google.maps.Map(document.getElementById("#{field.dom_name}"), myOptions);
+
+  - if form.object.send(field.name) && form.object.send(field.longitude_field)
+    :plain
+      marker = new google.maps.Marker({
+        position: new google.maps.LatLng(#{form.object.send(field.name)},#{form.object.send(field.longitude_field)}),
+        map: map
+      });
+
+  :plain
+      google.maps.event.addListener(map, 'click', function(e) {
+        updateLocation(e.latLng);
+      });
+
+      function updateLocation(location) {
+        if(marker) {
+          marker.setPosition(location);
+        } else {
+          marker = new google.maps.Marker({
+            position: location,
+            map: map
+          });
+        }
+
+        map.setCenter(location);
+        jQuery("##{field.latitude_dom_name}").val(location.lat());
+        jQuery("##{field.longitude_dom_name}").val(location.lng());
+      }
+
+    });
 %div.ramf-map-container{:id => field.dom_name, :style => "width:300px;height:200px"}
-= form.send :hidden_field, field.name
-= form.send :hidden_field, field.longitude_field
+= form.send :hidden_field, field.name, :id => field.latitude_dom_name
+= form.send :hidden_field, field.longitude_field, :id => field.longitude_dom_name

lib/rails_admin_map_field/rails_admin/config/fields/types/map.rb

@@ -2,6 +2,8 @@ module RailsAdmin::Config::Fields::Types
   class Map < RailsAdmin::Config::Fields::Base
     RailsAdmin::Config::Fields::Types::register(:map, self)
 
+    # THe name of the corresponding longitude field to match the latitude field
+    # in this object.
     register_instance_option(:longitude_field) do
       :longitude
     end
@@ -10,20 +12,32 @@ class Map < RailsAdmin::Config::Fields::Base
       :form_map
     end
 
+    # Google Maps API Key - optional
     register_instance_option(:google_api_key) do
       nil
     end
 
+    # Latitude value to display in the map if the latitude attribute is nil
+    # (Otherwise the location defaults to (0,0) which is in the Gulf of Guinea
     register_instance_option(:default_latitude) do
       51.5 # Latitude of London, United Kingdom
     end
 
+    # Longitude value to display if the longitude attribute is nil
     register_instance_option(:default_longitude) do
-      -0.5 # Longitude of London, United Kingdom
+      -0.126 # Longitude of London, United Kingdom
     end
 
     def dom_name
-      @dom_name ||= "#{bindings[:form].object_name}_#{@name}_#{@longitude_name}"
+      @dom_name ||= "#{bindings[:form].object_name}_#{@name}_#{@longitude_field}"
+    end
+
+    def latitude_dom_name
+      @lat_dom_name ||= "#{bindings[:form].object_name}_#{@name}"
+    end
+
+    def longitude_dom_name
+      @lon_dom_name ||= "#{bindings[:form].object_name}_#{@longitude_field}"
     end
   end
 end