about to jump into creating an extension, quick question

Id like to start making a simple extension for android (since i have experience coding with the platform... then maybe get it to work with pc and IOS later, i havent tried to make my own extension yet,  any good reading or examples to start with?
Can you use android studio to create an extension?  Or do you need to use eclipse netbeans ect?

I would suggest looking at the current Android extensions available and seeing how those work.  For editing I just use a text editor.  You could use something more complex but you'll most likely be editing only one Java file anyway.  Regardless of platform, you'll need Haxe code to connect to the native code.