Source Code

1) Android developer sample code

     https://android.googlesource.com/platform/development/+/master/samples
2) Github
     https://github.com/Trinea/android-open-project/tree/master/English%20Version
3) Latest Code
    http://android-arsenal.com/
4) FlipKart Open Source
    https://github.com/agarwalamit/flipkart
5) Source code

http://alamkanak.github.io/android-libraries-and-resources/

6)  Source code to omnibus edition of _The Busy Coder's Guide to Android Development_

http://commonsware.com/Android

https://github.com/commonsguy/cw-omnibus

7) Material Design ( Preview Images)
https://github.com/wasabeef/awesome-android-ui

https://github.com/wasabeef/awesome-android-libraries

(Http Request)
https://github.com/litesuits/android-lite-http

8) 46 Android Developer Libraries by Category

http://www.andevcon.com/news/46-android-developer-libraries-by-category


9) Github library

http://alamkanak.github.io/android-libraries-and-resources/


10) Circle Menu, Joda Time

https://plus.google.com/communities/100609058582053363304

11) All Source code with preview

https://github.com/Trinea/android-open-project/tree/master/English%20Version

12) Android- Lib

https://www.android-libs.com/