watchOS Development Expert

Build, configure, and optimize Apple Watch applications using SwiftUI, WatchKit, and watchOS-specific frameworks.

トピック別リファレンス

作業内容に応じて該当ファイルを Read してから着手する（progressive disclosure: 必要なトピックだけ読む）。

作業内容	参照ファイル
Watch アプリの基本 View / Navigation / Digital Crown / Always-on	topics/swiftui-watchos.md
iPhone ⇔ Watch 通信 (WatchConnectivity)	topics/watch-connectivity.md
Complications (WidgetKit) / Timeline Provider	topics/complications.md
HealthKit 連携 (認可・クエリ)	topics/healthkit.md
Workout トラッキング (HKWorkoutSession)	topics/workout-tracking.md
パフォーマンス最適化 (メモリ・バッテリー・背景処理)	topics/performance.md

以下の Quick Reference / Project Structure / Version Compatibility / Common Issues / Testing は常に有効な横断情報。

Quick Reference

Task	Command
Build Watch simulator	xcodebuild -destination 'platform=watchOS Simulator,name=Apple Watch Series 10 (46mm)' build
List Watch simulators	xcrun simctl list devices 'watchOS'
Pair Watch to iPhone	Use Xcode's "Devices and Simulators" window
Clean DerivedData	rm -rf ~/Library/Developer/Xcode/DerivedData/PROJECT-*

Project Structure

Multi-target Watch App (with iOS companion)

MyApp/
├── MyApp/                     # iOS app target
│   ├── MyAppApp.swift
│   └── ContentView.swift
├── MyWatch Watch App/         # watchOS app target
│   ├── MyWatchApp.swift
│   ├── ContentView.swift
│   └── Assets.xcassets
└── Shared/                    # Shared code between iOS and watchOS
    └── SharedModels.swift

Standalone Watch App

MyWatchApp/
├── MyWatchApp Watch App/
│   ├── MyWatchAppApp.swift
│   ├── ContentView.swift
│   └── Assets.xcassets
├── MyWatchApp Widgets/        # WidgetKit complications target (see topics/complications.md)
└── Package.swift              # Optional SPM dependencies

watchOS Version Compatibility

API Changes by Version

watchOS 10+ Only	watchOS 9 Compatible
TabView (vertical paging, .verticalPage)	PageTabViewStyle()
.containerBackground()	Custom backgrounds
New Workout APIs	WorkoutKit basics
Smart Stack widgets	Basic complications

Minimum Deployment Target

# XcodeGen project.yml
options:
  deploymentTarget:
    watchOS: "9.0"

Common Issues

Error	Solution
Watch simulator not paired	Open Xcode → Window → Devices and Simulators → Pair with iPhone simulator
WCSession not reachable	Check both Watch and iPhone apps are running, use transferUserInfo for queued delivery
Complication not updating	Ensure Timeline returns proper refresh policy, call WidgetCenter.shared.reloadAllTimelines()
HealthKit authorization failed	Check entitlements and Info.plist descriptions are set
Background refresh not working	Verify WKApplication background modes capability enabled

Testing on Simulator

1. Open Xcode → Window → Devices and Simulators
2. Create iPhone and Watch simulator pair
3. Select Watch scheme in Xcode
4. Choose paired Watch simulator as destination
5. Run (Cmd + R)

Tip: Test WatchConnectivity by running both iPhone and Watch apps simultaneously in their respective simulators.

Resources

• watchOS Human Interface Guidelines
• WatchKit Documentation
• WidgetKit for watchOS
• HealthKit
• WatchConnectivity
• WorkoutKit

Source

Custom skill created based on Apple's official watchOS documentation and best practices.