<%= link_to image_tag(url_to_avatar(activity.author), :width => "50", :height => "50"), user_path(activity.author_id), :alt => "用户头像" %>
<%= render :partial => 'users/show_detail_info', :locals => {:user => activity.author} %>
<% if activity.try(:author).try(:realname) == ' ' %>
<%= link_to activity.try(:author), user_path(activity.author_id), :class => "newsBlue mr15" %>
<% else %>
<%= link_to activity.try(:author).try(:realname), user_path(activity.author_id), :class => "newsBlue mr15" %>
<% end %>
TO
<%= link_to "班级资源", course_files_path(activity.course), :class => "newsBlue ml15" %>
<%= link_to activity.filename, course_files_path(activity.course), :class => "postGrey" %>
文件大小：
<%= number_to_human_size activity.filesize%>
上传时间：<%= format_time(activity.created_on) %>