Where can I find the source code for real android applications?

Question

Java

I work alone, I would like to somehow improve my skills, see real applications (how it is organized / made up).
Interested in various applications, except for games. Does anyone know where the source database is?
Or tell me how to efficiently search on github. For example, I want to see how the reservation application is made, for example, queues at the clinic or fitness, etc.
Thank you!

Answer 1

Check out the GitHub repository for links to open source Android projects. Projects are sorted into categories. https://github.com/pcqpcq/open-source-android-apps

Answer 2

https://f-droid.org/

Answer 3

Get started here https://android.googlesource.com/platform/packages...
These are the source code for embedded apps. There are very elegant solutions and the quality of the code is high.

Answer 4

https://fossdroid.com/

Answer 5

https://delphifmandroid.blogspot.com/2014/?m=1
Delphi XE8 sources for Android 4.4.2-9.0

Answer 6

I always download the themes I need, we source android from https://codekent.com . for free.