Xcode

IDE for developing apps for Apple platforms.

When to Use

• iOS/iPadOS app development
• macOS app development
• watchOS/tvOS development
• Swift Package development

Quick Start

// App.swift
@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

// ContentView.swift
struct ContentView: View {
    var body: some View {
        Text("Hello, World!")
    }
}

Core Concepts

Project Configuration

// Build Settings
// - Deployment Target: iOS 17.0
// - Swift Language Version: 6.0
// - Build Configuration: Debug/Release

// Info.plist keys
/*
<key>CFBundleDisplayName</key>
<string>My App</string>
<key>NSCameraUsageDescription</key>
<string>Camera access needed for photos</string>
*/

Debugging

// LLDB commands
// po variableName
// expr variableName = newValue
// bt (backtrace)

// Breakpoint actions
// Log message: "Value: @value@"
// Shell command: say "breakpoint hit"

// View debugging
// Debug > View Debugging > Capture View Hierarchy

Common Patterns

Schemes & Configurations

Project Settings:
├── Configurations
│   ├── Debug
│   ├── Release
│   └── Staging (custom)
└── Schemes
    ├── MyApp (Debug)
    ├── MyApp (Release)
    └── MyApp (Staging)

Code Signing

# Automatic signing
# - Team: Select your team
# - Automatically manage signing: ON

# Manual signing (CI)
# - Provisioning Profile: Select manually
# - Signing Certificate: Select manually

# Build from command line
xcodebuild -project MyApp.xcodeproj \
  -scheme MyApp \
  -configuration Release \
  -archivePath build/MyApp.xcarchive \
  archive

Best Practices

Do:

• Use SwiftUI previews
• Enable strict concurrency checking
• Configure proper entitlements
• Use Instruments for profiling

Don't:

• Commit derived data
• Ignore deprecation warnings
• Skip accessibility testing
• Use force unwrapping

Troubleshooting

Issue	Cause	Solution
Signing error	Certificate expired	Renew in developer portal
Preview crash	Build error	Check Preview canvas logs
Simulator slow	Resource constraint	Reset simulator

References

• Apple Developer Docs
• Xcode Help