您可以执行以下操作:

# activites/index.html.erb
<% @activities.each do |activity| %>
  # etc.

  <%= render "comments/comments", comments: activity.comments %>
  <%= render "comments/form" %>
<% end %>

# comments/_comments.html.erb
<% comments.each do |comment| %>
  # your code to display each comment
<% end %>

您可以看到我向render方法传递了一个参数:

You can see that I passed an argument to the render method:

render "comments/comments", comments: activity.comments

它将给_comments部***部变量comments，它等于activity.comments.

It will give to the _comments partial the local variable comments which will be equal to activity.comments.

您甚至可以使用form部分执行几乎相同的操作:

You can even do the almost-same-thing with the form partial:

# activites/index.html.erb
<%= render "comments/form", new_comment: Comment.new(commentable_id: activity.id, commentable_type: activity.class.model_name) %>

# comments/_form.html.erb
<% form_for new_comment do |f| %>

此外，Ruby on Rails中的一个好习惯是不要创建多个实例变量@like_this_one.将其保持在最低限度，因为它可能会造成混淆.我还要补充一点，您的变量命名也很重要.

Also, a good practice in Ruby on Rails is to not create several instance variables @like_this_one. Keep it to the minimum because it can be confusing. I will add that your variable naming is important too.

以下内容:

@activity = Activity.find(params[:id])
@commentable = @activity
@comments = @commentable.comments

可以重构为:

@activity = Activity.find(params[:id])

然后在您的视图中，您可以通过以下方式访问评论:

And then in your views you could access to the comments by doing:

@activity.comments