Snapp Mobile iOS Newsletter

Issue 74 • January 9, 2026

Hi folks!

2026 is officially underway — a good moment to reflect on goals for the year ahead. Learning is at the heart of growth, whether you’re exploring new technologies or deepening expertise in areas you already know. AI will play a significant role in our industry, and curiosity will be our greatest asset. Let’s lead and shape what comes next.

Apple’s Hello Developer: January 2026 is packed this month — SwiftUI foundational sessions, Liquid Glass design activities, Foundation Models tutorials, and coding intelligence experiments. Don’t miss Explore the foundations of SwiftUI if you haven’t registered yet.

In this issue, we’re covering on-device AI prompting, SwiftUI state quirks, SF Symbol animations, and the art of app icon design. Stay curious, and enjoy this week’s picks!

AI/ML

Prompting an on-device foundation model

Struggling to get reliable results from on-device foundation models? Apple Developer reveals critical prompt engineering strategies that reduce hallucinations and maximize performance on smaller models.

SwiftUI

Supporting SwiftUI Sidebar Selection with Multiple Data Types

How do you handle sidebar selection when items have different data types? Mark Szymczyk demonstrates using enums with associated values and the .tag modifier.

Creating and Opening Custom Document Types in SwiftUI

Building a document app? Gabriel Theodoropoulos walks through registering custom file types and handling file opening in SwiftUI.

Animating SF Symbols in SwiftUI

Want icon animations without custom drawing code? Natalia Panferova showcases SwiftUI symbol effects and content transitions.

Why Child State Won’t Update from Parent in SwiftUI

Why doesn’t your child view’s @State update when the parent changes? Xu Yang demystifies SwiftUI view identity and data flow patterns.

Solving SwiftUI Pain Points and Performance Bottlenecks: Zipic Development Technical Retrospective

How do you optimize SwiftUI for macOS while achieving native performance? Shili presents technical solutions from building Zipic.

Framework

Storing Swift structs in UserDefaults

Why does Codable work for UserDefaults initially but break during migrations? Natascha Fadeeva explains the migration pitfalls when models change and an alternative approach using individual properties.

Development

Icon Composer: Transforming an AI-generated icon

Can AI generate production-ready app icons? Antoine van der Lee collaborates with designer Michael Flarup to explore Icon Composer and the gap between AI-generated and professional icons.