如何在ActiveAdmin中过滤IS NULL？ [英] How to filter IS NULL in ActiveAdmin?

问题描述

我有一个表，该表带有一个名为 map_id的整数列，我想添加一个activeadmin过滤器以过滤此列是NULL还是IS NOT NULL。

I've a table with an integer column called "map_id", I want to add an activeadmin filter to filter if this column IS NULL or IS NOT NULL.

如何实现？

我尝试了以下过滤器

filter :map_id, :label => 'Assigned', :as => :select, :collection => {:true => nil, :false => ''}

但是，我收到以下错误消息：

But, I get the following error message :

未定义方法 map_eq，用于＃

undefined method `map_eq' for #

推荐答案

找不到很好的解决方案，但这是一个方法。 Active_admin的
过滤器由meta_search完成，您可以覆盖模型中meta_search自动生成的函数以获得所需的行为，最好的方法是使用范围，因为您需要返回一个关系才能此处

Not found a good solution but here is a how. filters of Active_admin are accomplished by meta_search, you can override the functions automatically generated by meta_search in your model to get the behavior that you want, the best way is to use the scope since you need to return a relation in order to chain with other query/scopes, as stated here

在您的模型中：

用于：as =>：选择过滤器，acitve_admin使用_eq wheres，这里是源代码

for :as=>:select filters, acitve_admin use the _eq wheres, here is the source code

scope :map_eq, 
        lambda{ |id|
        if(id !='none')
            where( :map_id=> id)
        else
            where( :map_id=> nil)
        end
        }

#re-define the search method:
search_method :map_eq, :type => :integer

：

filter :map_id, :label => 'Assigned', :as => :select, :collection => [['none', 'none'], ['one', 1],['tow', 2]]

# not using :none=>nil because active_admin will igore your nil value so your self-defined scope will never get chained.

希望获得帮助。

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