A single-view iOS app that simulates a set of traffic lights at an intersection.
The traffic lights should be arranged North-South and East-West like a compass. And there should be a button to start/stop the animation.
When switching from green to red, the yellow light must be displayed for 5 seconds prior to it switching to red. The lights will change automatically every 30 seconds.
The app should be written using Swift 3. Any external libraries should be included in the project directly.
ProjectGenerator and Struct are used to manage Xcode project file, that makes it easy to merge conflicting changes on project settings and/or new/renamed files in the project. Carthage is being used to install 'ProjectGenerator' source files into the project.
Fastlane is being used for routine tasks automation, such as generate/regenerate project file and increment project version/build number.
CocoaPods helps managing dependencies, all dependencies are stored in the repo, so the app codebase is ready to build and run out of the box.
R.swift is used to improve development experience and eliminate errors when working with resources.
To see the source code - open the TrafficLights.xcworkspace file.
The app is built using the "unidirectional data flow" and "finite state machine" design patterns.
High level app architecture is implemented using UniFlow framework. See introduction, theoretical fundamentals and methodology overview to better understand how app data model and business logic are organized.
All source files are grouped into 2 big groups - Model (that represents data model and business logic) and View (that implements presentation logic and is responsigle for passing user input to the Model layer). The View types rely on Model types, while Model types know nothing about View.
All Model files start with M. prefix, while all View - with V. prefix. AppDelegate.swift file supposed to be part of V.Delegate file inside View folder/group, but kept with traditional name and at the top level to help developers who are unfamiliar with such naming conventions to find initial entry point faster.
The Preview.storyboard is not included in the app bundle, because it's only needed for developer convenience to preview views during development in real time without running the app. To make it work, the V_Root_View class is named this way and is not nested (ti is supposed to be nested inside V.Root type and have ful name like this: V.Root.View) due to limitations of IB Storyboards - nested types are not supported for view custom class on storyboards.
To give the code better structure, Swift "nested type" feature is widely used. If a type is not supposed to be ever instantiated, it's declared as enum without any single case. Outer type works as scope for nested types.
MKHState framework is used to manage GUI states (View classes).