how to run a service which updates the appwidget?

I am having a home screen widget and i want to run a background service which does all the fetching from url and should update all the w开发者_开发技巧idgets on the home screen corresponding to the provider i have created it.

how to do it? it seems that i unable to access appwidget or the context from the service.

any help?

my response here should be helpful to you android appwidget won't update from activity