You can find free Android code along with their illustration.
"Freecode Android Tutorial" application is packed with full detailed tutorials and interacting outputs to make you understand every aspect of android app developement.
User can now find all code and illustration in a single android application. This application cover all the material design themes as well as social logins. Custom demonstration and
code is also provided which will help user to gain the knowledge of android. Best way to learn android.. Topics included are:
1) Toolbar , Dailogs.
2) Navigation View , ListView , ViewPager
3) Recycler View.
4) Card View.
5) Tab Layout.
6) Snack Bar.
7) Floating Action Button.
8) Floating Text.
9) Animations
10) Tabs Layout
11) Social Login
12) Splash Screen
13) Selectors"
14) Notifications - Local and Firebase Notification
15) Use of Volley , Json Parsing and Sqlite
and many more topics
App will have the future support with updates and you will get to know first when something new is introduced in material design.