title: Get url argument to process generic views
body: <p>I would like to write a one-template view, which depending on the url path will show different field of the model. So for instance if path is </p>
  
  <pre><code>http://127.0.0.1:8000/trip/2/1/
  </code></pre>
  
  <p>I will get second trip from my db (that works), and <code>1</code> should give (as html is written) a description field. I don't know how to process this to <code>context_processor</code> in my view. Do you have any ideas?</p>
  
  <p>views.py</p>
  
  <pre><code>class TripDescriptionCreate(LoginRequiredMixin, UpdateView):
  
      model = Trip
      template_name = 'tripplanner/trip_arguments.html'
      fields = ["description", "city", "country", "climate", "currency", "food", "cost", "comment", "accomodation",
      "car", "flight", "visa", "insurance", "remarks"]
      context_object_name = 'trips'
      success_url = '/'
  
      def form_valid(self, form):
          form.instance.author = self.request.user
          return super().form_valid(form)
  </code></pre>
  
  <p>trip_arguments.html</p>
  
  <pre><code> &lt;form method="POST"&gt;
              {% csrf_token %}
              &lt;fieldset class="form-group"&gt;
                  &lt;legend class="border-bottom mb-4"&gt;{{ trips.tripName }}&lt;/legend&gt;
                      {% if field_id == 1 %}
                          {{ form.description|as_crispy_field }}
                      {% elif field_id == 2 %}
                          {{ form.city|as_crispy_field }}
                      {% endif %}
              &lt;/fieldset&gt;
              &lt;div class="form-group"&gt;
                  &lt;button class="btn btn-outline-info" type="submit"&gt;Update&lt;/button&gt;
              &lt;/div&gt;
          &lt;/form&gt;
  </code></pre>
  
  <p>urls.py</p>
  
  <pre><code>path('trip/&lt;int:pk&gt;/&lt;int:field_id&gt;', TripDescriptionCreate.as_view(), name='trip-fullfill'),
  </code></pre>