Kein Li

Building out a mini iOS Manga App

· Kein Li

Building Out a Mini iOS Manga App

Finally getting back into building iOS apps after a ~2 year hiatus. It’s been awhile since I built something outside of work. I started with watching some CS193P lectures and followed along for a few lectures before I got bored and decided the best way to learn is to build anything ASAP.

Personally I think using AI tools is awful when learning something new and having it write the code for you is awful. I use it strictly for learning purposes like “Explain Swift Concurrency” or “Is my code idiomatic?” or hints on how to approach a problem

Notes

  • Navigation and TabViews

    • NavigationStack and TabView did not initially work well together.
    • Each TabView required its own NavigationStack for navigation titles to behave properly.
    • Applying a universal background color did not work globally; it only applied correctly within each TabItem view.

  • Use of Enums

    • Enums were used to manage both navigation and loading states.
    • Navigation was wrapped in a Route enum and switched inside .navigationDestination.
    • Loading state enum contained: Idle, Loading, Success, and Error, where Loaded and Error contained the data and error message respectively so I can switch on the state and either display the data or the error message.

  • Error Handling

    • Network calls threw specific NetworkError enums.
    • Covered decoding, URL, and networking errors.
    • Errors were mapped to a user-friendly error message struct stored inside the loading state.

  • Async/Await

    • Used async/await functions along with the .task modifier for background HTTP calls.
    • Implemented an HTTP client layer injected into view models.
    • Followed Dependency Injection and separation of concerns principles.

  • .task Modifier with id

    • The id property re-runs the task whenever the id changes.
    • Used this to auto-refetch when query/filter properties changed.
    • Watched a struct for changes and re-ran loadManga().
    • Allowed reuse of the same function for initial load and future refetches (e.g., filter changes).

  • View Models

    • Used ObservableObjects to manage state for each view.
    • Each view model had its own HTTP client instance.
    • Followed Dependency Injection and separation of concerns principles.