Advanced Android App Development by Google
It's free course prepaid by Google to improve yours Android Development skill to Advanced level.
List of topics:
- Fragments
- Libraries
- Firebase Cloud Messaging
- Places
- Media Playback
- Widgets
- Espresso
- Publishing Your App
After my first look on this course I'am sure that you need to be at least after previous (also free) courses from Google, as always use language and examples are easy to understand. So if You are interested to grow up Your skill level You should take a look on this.
Link to course:
https://www.udacity.com/course/advanced-android-app-development--ud855