Django readonly field only on change, but not when creating

Question

I have a Team model whit players ManyToManyField, and I want to be able to add Players to a new team when created, but not able to modify it after created.

If I make the players field readonly like this:

# admin.py class TeamAdmin(admin.ModelAdmin)     readonly_fields = ['players']  admin.site.register(Team, TeamAdmin) 

I will not be able to add players to a new Team. How can I make the players field "readonly after created" or something like that?

Answer 1

You need to override get_readonly_fields() method of your admin class.

# admin.py class TeamAdmin(admin.ModelAdmin)     ...      def get_readonly_fields(self, request, obj=None):         if obj: #This is the case when obj is already created i.e. it's an edit             return ['players']         else:             return []