Code guidelines

• Use Kotlin.
• Keep it simple!
• Keep functions and classes reasonably short.
• Minimize side effects.
• Avoid force unwrap (!!) and lateinit. If needed, use ?: throw Exception("Meaningful message").
• Use extensions.
  • If they are shared, put them in a file <ClassName>Extensions (e.g. TextFieldExtensions.kt)
  • If they are specific to a class/file, make them private.
• Use idiomatic Kotlin (let, apply, also, etc.). But keep readability in mind! Often a simple if != null is better.
• Prefer composition over inheritance.
• Prefer immutability.
• Prefer explicit type declarations for instance variables.
• Use readable names.
• If something is difficult to understand, add some documentation.
• Use Rx in services / repos / business logic / view models and live data only to interface with the UI.
• Use View binding.
• Don't use ViewPager. User RecyclerView with SnapHelper or ViewPager2
• Use static imports where possible (e.g. enums, string or drawable resources). This improves readability. It makes writing / copy pasting a bit annoying but reading is more frequent. Just place cursor over code and press ALT+ENTER. AS will offer the import.