(This book is the best introduction book for Android beginners. The book systematically explains all aspects of Android software development from simple to deep. Chapter 1 leads you to build an Android development environment and implement your first Android program. Chapters 2 to 13 completely explain various basic knowledge and key technologies in Android development, including four components, UI, fragments, broadcast mechanism, data storage, services, multimedia, network, location services, sensors, and the use of distributed version control system Git. In some chapters, advanced skills of related technologies will be crossed. Chapters 14 and 15 will lead you to write a complete project, teaching you how to package, launch, embed advertising and make profits. The content of this book is easy to understand, which is suitable for beginners to read step by step, or as a reference manual to consult at any time. This document includes the following annexes:)