How can I learn more about event handling, OOP design patterns, architectures.

Question

I think if sololearn add some courses covering those areas it will be great opportunity..

Answer 1

They are many different sources but some are better than other: http://www.oodesign.com/
On this website you can see the interest of each design pattern and you also have some code to make it easier to implement in your own way.

Answer 2

Google, Stackoverflow, books....