A photo of me

I‘m writing an app

The last two weeks I‘ve spent quite some time on evenings and weekends to work on an iOS app. I won’t tell you what it is though, it‘s way too early for that.

This is the first post in a series and this one is about technologies and tooling. See all posts in this series.

Technologies

I‘m writing a native app in Swift and UIKit.

The decision against using React Native or any other third-party mobile technology was mostly because native feels better (to me), is often faster and gets new features first. Using React Native would have sped up the development process a lot (mostly because I know that technology and my Swift/UIKit knowledge is a little rusty), but I wanted it to be native and I‘m in no rush.

The project was initially set up to use SwiftUI as it seems to be the future of iOS development, but I quickly hit some limits. More experienced iOS-Developers would have probably found a way around it, but I feel more at home with UIKit and it‘s a stable, battle-tested technology.

Tooling

Spending most of my working time writing Go I‘ve come to value automatic formatting and good linting. For that I‘m using SwiftFormat and SwiftLint, both with the default configuration. You can configure Xcode to automatically run those when building, which I highly recommend.

For dependency management I've started using Carthage, mostly because that was the defacto-standard when I last wrote an app. But I've switched over to Swift Package Manager because it has great Xcode-integration and is generally stable.

Most iOS developers have experienced their share of .xcodeproj-related merge conflicts or weird diffs. Generally I prefer all files in my project to be human-readable. For that I've used XcodeGen, which allows you to define your project in a simple project.yml and ignore your project with these lines in you .gitignore:

*.xcodeproj
!*.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

That means that on CI, new clones or changes in project.yml you need to install XcodeGen and run xcodegen generate to set it up, but for me that's worth it.

Talking about CI, I've set up Fastlane for linting and testing. It allows easy definition of rules and automatic TestFlight or even AppStore submissions (including taking screenshots), which is awesome. It also has a ton of plugins.

Since Travis CI costs a small fortune for private repositories I've migrated away and now use GitHub Actions. It took some time to configure it right, so here's my .github/workflows/ci.yml, hoping it's useful for some people:

name: CI

on: [push]

jobs:
lint-and-test:
runs-on: macos-latest
steps:
- run: sudo xcode-select -s /Applications/Xcode_11.5.app/Contents/Developer
- name: Checkout code
uses: actions/checkout@v2
- name: Cache Bundler
uses: actions/cache@v2
with:
path: vendor/bundle
key: $-gems-$
restore-keys: |
$-gems-

- name: Cache Swift Package Manager
uses: actions/cache@v2
with:
path: .build
key: $-spm-$
restore-keys: |
$-spm-

- name: Install dependencies
run: |
bundle update --bundler
bundle install
brew install xcodegen swiftlint swiftformat

- name: Generate Xcode project
run: xcodegen generate
- name: Lint
run: bundle exec fastlane lint
- name: Test
run: bundle exec fastlane test

That's my setup so far. If you have any questions or suggestions, hit me up.