Question

I’m challenging a annoying problem in rails.

I have a view and I’m trying to render a partial, but only when @prev_activity != message.about like this:

<%= @prev_activity != message.about ? render(:partial => "dashboards/stream_activity", :locals => { :activity => message.about }) : render(:text => "")  %>

In dashboards/_stream_activity.html.erb I render some content and also set previous activity variable:

<% @prev_activity = activity %>

It does not work because rails render dashboards/_stream_activity.html.erb before @prev_activity != message.about is checked, so @prev_activity is equal to message.about.

Is there any way to solve this one?

Answer 1

I’ve finally found solution for that. In view where I render the collection I set @prev_activity to nil.

<% @prev_activity = nil %>
<%= render :partial => "dashboards/stream_message", :collection => @workspace_stream.messages %>

than it works like expected in dashboards/_stream_message.html.erb:

<% if @prev_activity != message.about %>
  <%= render partial: "dashboards/stream_activity", locals: { activity: message.about }%>
<% end %>

dashboards/_stream_activity.html.erb:

<% @prev_activity = activity %>

setting @prev_activity to nil in controller didn’t work as well as all the other solutions posted here.