I work with android for some time and familiar with the .aar project file which can be created in android studio and wrappes a module with classes and etc.

After that aar is created every project can add it as a mudule dependency and use its method and activities.

In Eclipse that will work as a reference project.

1. My question is how can it be done with IOS?
I am looking for a way to create some code that existing apps can easily take to their project and use it. looking for directions
2. Say an IOS app can be coded with Objective-c or swift. If I build a code in swift can it be used in both existing codes (objective and swift)?