How can I show all products and their counts together in one place in Spree Commerce? The only place I see the count_on_hand implemented is in admin/stock_transfers and even then it's several clicks deep for the administrator.
admin --> configuration --> stock transfers --> view transfer
and then you can see a count on hand variable displayed per item.
Each product has a total on hand method defined here:
https://github.com/spree/spree/blob/v2.2.2/core/app/models/spree/product.rb#L200-L206
You can iterate through all products, and call total_on_hand to find the number of those products on hand (for all variants and stock locations).
来源：https://stackoverflow.com/questions/24248395/show-all-spree-ecommerce-products-together-with-their-count-on-hand-displayed