Here are some useful resources for Android development.
Internationalization
Design
- Android Asset Studio
- Android Cheatsheet for Graphic Designers
- Android Developer Icons
- Android Icons
- Material icons guide
- Android Transition animations explanation with examples
Fragments
Asynchronism
Security
Libraries
- Android Arsenal
- Libraries for developers
- Top 5 Android libraries every Android developer should know about
Finalizing the app / promoting it
- Free iPhone Mockup Generator & App Demo Videos by Placeit
- Device Art Generator
- Android App Publishing Checklist
Testing
Continuous Integration
- Use GoCD for Android and get rid of Jenkins
- DevOps on Android: From one Git push to production and the talk given by the author
- Continuous Integration on Android