Transit Stop Viewer

Project roadmap

1. 01

   Choose the data source and model it

   ~1.5h

   Pick a transit API with a free key or no key, or, to start simply, a JSON file you host yourself (for example a GitHub Gist) with stops and departures. Write down its two requests (search stops, get departures for a stop) in README.md, and create Codable structs matching the JSON. Done when: a sample JSON response decodes into your structs in a unit test.

2. 02

   Create the saved stops list

   ~1.5h

   Create a SwiftUI app with a SwiftData model SavedStop (stop id, name, and an optional nickname such as Home). The main screen lists saved stops with @Query, and can delete one by swiping. Show a friendly message when the list is empty. Done when: stops added in code appear in the list, and are still there after restarting the app.

3. 03

   Search and save stops

   ~2h

   Add a search screen with a search field (.searchable) that calls the stop search with URLSession and async/await, waiting until the user stops typing for a moment before searching. Tapping a result saves it (unless it's already saved) and goes back. Done when: searching finds stops, and saving one adds it to the main list.

4. 04

   Show departures

   ~2h

   Tapping a saved stop opens a screen that loads its departures and shows each one's line, destination and minutes until departure ("Now" when under a minute). Add pull-to-refresh with .refreshable. Show a loading spinner, an error message with a Retry button when the request fails, and a message when there are no departures. Done when: departures load, refresh, and errors are shown clearly.

5. 05

   Handle edge cases

   ~1.5h

   Test with the phone offline, with a stop that no longer exists, and with a response missing fields, and make sure the app never crashes: show a message instead. Make the minutes count update every 30 seconds while the screen is open. Done when: every one of these cases shows a sensible message instead of crashing.

6. 06

   Test the app

   ~1.5h

   Write unit tests for decoding the JSON (a normal response and one with missing fields) and for the minutes-until-departure calculation, including departures in the past. Write a short checklist in README.md for testing by hand on a device. Done when: the unit tests pass, and the checklist is complete.

Resources

• DocsSwiftUI tutorials (Apple)
• DocsSwiftData documentation
• DocsFetching website data into memory (URLSession)
• ArticleHacking with Swift: Codable cheat sheet