Design Pattern for InternetCheck and other related function

I am developing an app that work only if there is internet connection. I use web service to get data,also upload images to server, GET and POST requests and etc.

I created function for that,and want to create one class that can be import in other activity files and call that functions which i need in that activity.

Something like my own custom library which can be used in my other application too.It reduce recode of basic functions which are used in multiple application.

Is there any Design pattern for this? Which make it simple and useful.