Good news: Android and iOS have a lot in common. Bad news: they have seriously big differences in approach, style and philosophy. This is a book + code bundle, including a comprehensive introduction to the Android ecosystem for iOS developers. DRM-free, in PDF (283 pages), EPUB, MOBI (Kindle) and self-contained HTML formats! Read it on any device, without restrictions. The bundled source code includes 46 projects with over 8000 lines of Java code, ready to be opened, executed and extended with Android Studio, including a small introduction to Kotlin!
A great book! As an iOS developer, I found the iOS and Android concept comparisons very helpful in understanding these new idioms.