Gmaps4rails: undefined method `model_name' for NilClass:Class

Hi All,

just in a spot of bother with this gem, I am trying to create a new
location and get the above msg.

here is my controller:

class LocationsController < ApplicationController

GET /locations

GET /locations.json

def index
@locations = Location.all
@json = Location.all.to_gmaps4rails
end
respond_to do |format|
format.html # index.html.erb
format.json { render json: @locations }
end
end

GET /locations/1

GET /locations/1.json

def show
@location = Location.find(params[:id])
@json = Location.all.to_gmaps4rails
respond_to do |format|
format.html # show.html.erb
format.json { render json: @location }
end
end

GET /locations/new

GET /locations/new.json

def new
@location = Location.new
@json = Location.all.to_gmaps4rails

respond_to do |format|
  format.html # new.html.erb
  format.json { render json: @location }
end

end

GET /locations/1/edit

def edit
@location = Location.find(params[:id])
@json = Location.all.to_gmaps4rails
end

POST /locations

POST /locations.json

def create
@location = Location.new(params[:location])
@json = Location.all.to_gmaps4rails
respond_to do |format|
if @location.save
format.html { redirect_to @location, notice: ‘Location was
successfully created.’ }
format.json { render json: @location, status: :created,
location:
@location }
else
format.html { render action: “new” }
format.json { render json: @location.errors, status:
:unprocessable_entity }
end
end
end

PUT /locations/1

PUT /locations/1.json

def update
@location = Location.find(params[:id])
@json = Location.all.to_gmaps4rails
respond_to do |format|
if @location.update_attributes(params[:location])
format.html { redirect_to @location, notice: ‘Location was
successfully updated.’ }
format.json { head :no_content }
else
format.html { render action: “edit” }
format.json { render json: @location.errors, status:
:unprocessable_entity }
end
end
end

DELETE /locations/1

DELETE /locations/1.json

def destroy
@location = Location.find(params[:id])
@location.destroy
@json = Location.all.to_gmaps4rails
respond_to do |format|
format.html { redirect_to locations_url }
format.json { head :no_content }
end
end

and the _form I use to create the new location:

<%= form_for(@location) do |f| %>
<% if @location.errors.any? %>


<%= pluralize(@location.errors.count, “error”) %> prohibited
this
location from being saved:

  <ul>
  <% @location.errors.full_messages.each do |msg| %>
    <li><%= msg %></li>
  <% end %>
  </ul>
</div>

<% end %>

<%= f.label :id %>
<%= f.number_field :id %>
<%= f.label :name %>
<%= f.text_field :name %>
<%= f.label :coordinates %>
<%= f.text_field :coordinates %>
<%= f.label :course_id %>
<%= f.number_field :course_id %>
<%= f.label :college_id %>
<%= f.number_field :college_id %>
<%= f.submit %>
<% end %>

This is the error msg in full:

NoMethodError in Locations#new

Showing C:/Postgrads0204/app/views/locations/_form.html.erb where line
*#1

  • raised:

undefined method `model_name’ for NilClass:Class

Extracted source (around line #1):

1: <%= form_for(@location) do |f| %>

2: <% if @location.errors.any? %>

3:

4:

<%= pluralize(@location.errors.count, “error”) %>
prohibited this location from being saved:

Trace of template inclusion: app/views/locations/new.html.erb

Rails.root: C:/Postgrads0204
Application Trace http://localhost:3000/locations/new# | Framework
Tracehttp://localhost:3000/locations/new#
| Full Trace http://localhost:3000/locations/new#

app/views/locations/_form.html.erb:1:in
`_app_views_locations__form_html_erb___82209480_46213008’

app/views/locations/new.html.erb:3:in
`_app_views_locations_new_html_erb___810294894_46206828’

Any Ideas where am I going wrong?

Cheers

J

On 2 April 2013 15:34, Jax [email protected] wrote:

1: <%= form_for(@location) do |f| %>
The problem is nothing to do with the gem. @location is nil. Are you
passing the value across when you render the form? It seems to be the
only bit of code that you have not shown us. See
http://guides.rubyonrails.org/layouts_and_rendering.html#using-partials
for how to pass data to the form.

Also have a look at the Rails Guide on debugging with will show you
techniques that you can use to debug your code.

Colin

Hi Colin,

Thank you for your comment, I was actually missing a “end” tag to close
off
the class in the controller!

Cheers anyway

J

On 2 April 2013 17:06, Jax [email protected] wrote:

Hi Colin,

Thank you for your comment, I was actually missing a “end” tag to close off
the class in the controller!

A missing end tag in the controller code gave you the error “undefined
method `model_name’ for NilClass:Class”? That is unusual. I would
have expected to get a syntax error about the missing end when the
class was loaded.

Colin

i am using google maps for my project in rails 4, ruby 2, and
gmaps4rails ‘1.5.6’ but the problem is i am not getting marker at center
of the map as well as the zoom in zoom out side bar is also not coming.

If any one have any idea about this problem please reply?

Model Action
acts_as_gmappable

def gmaps4rails_address
html = full_address(city_id,state_id,country_id)
self.location = (location + html)
location
end

def full_address(city_id,state_id,country_id)
city_name = MdmCity.get_city_name(city_id)
state_name = MdmState.get_state_name(state_id)
country_name = MdmCountry.get_country_name(country_id)
html = “#{city_name} #{state_name} #{country_name}”
html
end

Controller Action

def edit_content
@location_json = SeoContent.where(:id =>
params[:id]).first.to_gmaps4rails
end

VIEW

<%= gmaps4rails(@location_json) %>

Issues for me.

  1. Zoom In and Zoom out bar is not coming.
  2. Marker is not coming at center.
  3. How to give Info window.
  4. How to raise that address is Invalid, which is not present on google
    map (Eg:kdjfkdfhdkfhd)
  5. Why this action (def gmaps4rails_address) is calling automatically.
  6. I want to call def gmaps4rails_address from update action too how ?
  7. Map is coming only one forth ?why
  8. Can i show directions on map ?

Thanks

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