I wonder how I can assign a custom Visualforce page to an object detail page on Salesforce1. Could anyone help me, please?
First you need to make this page available for SF1. And replace this page with View from Object setting page. Now from this page's action method check currently you are in SF1 or in desktop and if you are in desktop then redirect to standard page with parameter
baseurl/id?nooverride=1.In this way you can make this page available for SF1.