Kaminari已安装，但显然未见

Question

rails测试正在生成错误，如下所示

ActionView::Template::Error: undefined method `total_pages' for nil:NilClass

        options[:total_pages] ||= scope.total_pages

对于视图中的这一行：<%= paginate @carts %>

控制器操作根据以下逻辑生成空数组

    if user?
      @carts = Cart.order(created_at: :desc).where([user_id = ?, current_user.id]).page params[:page]
    else
      @carts = []
    end

卡米纳里

Using kaminari-core 1.2.2
Using kaminari-actionview 1.2.2
Using kaminari-activerecord 1.2.2
Using kaminari 1.2.2

puts @carts.size确实在日志记录中显示了0。因此，数组对象存在，但作用域没有激活。似乎kaminari的基本设置在这个特定的实例中没有启动，而在另一种情况下，@users = User.page params[:page]测试没有抱怨。

这是怎么解决的？

Answer 1

paginate []     # undefined method `total_pages' for []:Array
paginate nil    # undefined method `total_pages' for nil:NilClass
#        ^                                           ^
# NOTE: from the error it looks like @carts is nil --'

kaminari需要一个ActiveRecord类或关系对象，必须在该类/对象上调用page方法，以使其成为成为“分页的”，并使作用域生效：

paginate Cart             # => undefined method `total_pages' for Cart:Class
paginate Cart.all         # => undefined method `total_pages' for #<ActiveRecord::Rel...

paginate Cart.page(1)     # => <nav class="pagination" ...
paginate Cart.all.page(1) # => <nav class="pagination" ...

Kaminari有一个助手可以对数组进行分页：

@array = Kaminari.paginate_array([1,2,3]).page(1).per(10)

paginate @array           # => <nav class="pagination" ...

还可以使用空购物车关系对象：

paginate Cart.none.page   # => ""

https://github.com/kaminari/kaminari#paginating-a-generic-array-object