Hello

Firstly I Would like to remind you that both are really very well in their own perspectives, its up to you what do you want to choose as your career option.

The scope of android app developers is limited as it only develops apps only for android platform.    The scope of web development is not limited to any platform as we can access web apps over the internet.

Android development is a little difficult to learn and start as compared to web development.    Web development is a little easier to learn and start development than android development

Hope this information helps you.

GOOD LUCK!