Android Architecture Masterclass is designed to teach developers how to write clean, readable and maintainable code in your Android applications . Learn how to use MVC pattern and Dependency Injection to follow Separation of Concerns principle . Use clean packages structure to reflect the business domain of your application . Avoid “Spaghetti Code” and “God Classes” in this course . Learn the real roles of Activities and Fragments in Android applications and understand single-Activity vs. Multi-Activity trade-offs . Use MVC patterns to separate user interface logic in your codebase using MVC . Use Dependency-injection to avoid “God classes” in your apps .Authentication failed. Unique API key is not valid for this user.