1、消息为0的时候不显示 消息数和“全部设置已读”。

2、消息不为空，未读消息为空的时候不显示“全部设为已读”

app/views/users/user_messages.html.erb

@@ -29,12 +29,15 @@
   </div>
 <div class="resources mt10" id="users_setting">
 <div>
-<% if params[:type].nil? || params[:type] == "unviewed" %>
-    <div class="newsReadSetting">
-      有&nbsp;<span class="c_red"><%= unviewed_message(@user) %></span>&nbsp;条未读<a href="javascript:void(0);" class="ml15"><%= link_to "全部设为已读", user_message_path(User.current, :viewed => 'all') %></a>
-    </div>
-<% end %>
 <% if @message_alls.count >0 %>
+    <% if params[:type].nil? || params[:type] == "unviewed" %>
+        <div class="newsReadSetting">
+          有&nbsp;<span class="c_red"><%= unviewed_message(@user) %></span>&nbsp;条未读
+          <% unless unviewed_message(@user) == 0 %>
+              <a href="javascript:void(0);" class="ml15"><%= link_to "全部设为已读", user_message_path(User.current, :viewed => 'all') %></a>
+          <% end %>
+        </div>
+    <% end %>
     <%# 课程消息 %>
     <% unless @message_alls.nil? %>
         <% @message_alls.each do |ma| %>