NSLondon: AI Accelerated Mobile Development

AI can speed up iOS work without taking away your judgement. We’ll explore how to use AI tools effectively in real-world development, covering smarter autocomplete, chat, and agent-based coding. You’ll see quick demos modernising a small legacy app and building a new one from scratch, plus a short list of practical tips and resources to apply right away.

Transcript

1. AI Accelerated Mobile Development NSLondon 2025.5 Gio Scalzo
5. 📱 💻
6. The Four modes of AI Accelerated Dev
7. 2019 2021 2022 β
8. Autosuggestions - Instant keystrokes, narrow vision • Predict next block of code • Cuts boiler-pl a te, but missing bro a der context • Dev job: choose cle a r n a mes a nd review every suggestion
9. 2019 2021 2022 β Nov 2022 2023 Gpt4
10. Chat Assistants - A conversation with a runtime • Bro a der context • C a n suggests solutions to be a pplied • Help to n a vig a te • Dev role: m a ke the right questions, a pply c a refully the suggestions
11. 2019 2021 2022 β Nov 2022 2023 Mid 2024 Compose C a sc a de Gpt4
12. IDE Agents - Whole-project helpers • Index the entire repository • C a n a utonomously implementing fe a tures, f ixing bugs, migr a ting APIs, etc. • Dev role: set cle a rly the go a ls, inspect di ff s, a pprove a nd twe a k
13. Agents Orchestrator - A tech lead role • Multiple contexts • C a n work in multiple projects or multiple p a rts of the s a me project • Help to n a vig a te • Dev role: guide a nd orchestr a te di ff erent stre a ms of work
14. Agents Orchestrator - A tech lead role • Multiple contexts • C a n work in multiple projects or multiple p a rts of the s a me project • Help to n a vig a te • Dev role: guide a nd orchestr a te di ff erent stre a ms of work
15. Demystifying an AI Coding Agent
16. • A LLM model • A system prompt • A Ch a t loop • A set of tools th a t it c a n c a lls
23. https://gioscalzo.com/blog/demystifying-ai- coding-agents-in-swift/
24. Let’s put this into practice
25. Let’s build a macOS QRCode Generator • macOS app for generating QR codes • Text input field for the QR content • Button to generate and display the QR code • Export QR code as a PNG file • Sidebar to browse history and see previews
26. Preserve the Window Context: xcsift https://github.com/ ldomaradzki/xcsift
27. ╰─$ xcodebuild -scheme QRCodeApp -destination 'platform=macOS' test 2>&1 | xcsift -w { "summary" : { "errors" : 0, "build_time" : "23.320", "warnings" : 2, "failed_tests" : 0, "passed_tests" : 4 }, "status" : "success", "warnings" : [ { "line" : 332, "message" : "nil coalescing has non-optional type 'CGColor'", "file" : “QrCodeApp/QrCodeViewModel.swift" }, { "message" : "No AppIntents.framework dependency found." } ] } Preserve the Window Context: xcsift
28. Preserve the Window Context:ast-grep https://ast-grep.github.io/
29. Preserve the Window Context:ast-grep https://ast-grep.github.io/ # grep or search text You are operating in an environment where ast-grep is installed. For any code search that requires understanding of syntax or code structure, you should default to using ast-grep --lang [language] -p '<pattern>'. Adjust the --lang flag as needed for the specific programming language. Avoid using text-only search tools unless a plain- text search is explicitly requested.
31. Let’s do it!
32. Create a file named AGENTS.md that analyses the current macOS Xcode project and includes information regarding the following sections: # unit tests - Use XCTest for Unit and UI Tests. - Implement unit tests to ensure that the code works as intended. - Run the tests before making any changes, add tests to verify the changes, and ensure that the tests pass before considering the session complete. # xcodebuild To save context, use the tool xcsift to format the output of xcodebuild or Swift. OVERVIEW: A Swift tool to parse and format xcodebuild output for coding agents xcsift reads xcodebuild output from stdin and outputs structured JSON. Important: Always use 2>&1 to redirect stderr to stdout. This ensures all compiler errors, warnings, and build output are captured. Examples: - xcodebuild build 2>&1 | xcsift -w - xcodebuild test 2>&1 | xcsift -w - swift build 2>&1 | xcsift -w - swift test 2>&1 | xcsift -w # Structure hygiene Fix all errors, warnings, and failed tests, even if they are not related to the current changes being made. # grep or search text You are operating in an environment where ast-grep is installed. For any code search that requires understanding of syntax or code structure, you should default to using ast-grep --lang [language] -p '<pattern>'. Adjust the --lang flag as needed for the specific programming language. Avoid using text-only search tools unless a plain-text search is explicitly requested. # apple platforms tips Apple’s Essential Tips for iOS App Speed and Efficiency - Profile early and often using Instruments in Xcode 26. Identify bottlenecks in SwiftUI views and Foundation Model requests before you ship. - Optimise SwiftUI views by profiling view trees, caching expensive computations, and trimming main thread usage. Avoid repeated body - omputation to prevent dropped frames. - Streamline Foundation Model requests by reducing context payloads, removing redundant data, and keeping request windows small for faster - responses. - Make memory and algorithm improvements with Swift’s new InlineArray and Span types. Replace custom slow loops with built-in methods like - First(), and validate any speedups with flame graphs. - Accelerate app launch by deferring work not needed immediately. Move blocking network, file, and calculation calls off the main thread. - Minimise energy usage by using incremental updates instead of full reloads, and only fetching or displaying what users need right now. - Benchmark your changes and document optimisation decisions.
33. Create a file named AGENTS.md that analyses the current macOS Xcode project and includes information regarding the following sections:
34. # unit tests - Use XCTest for Unit and UI Tests. - Implement unit tests to ensure that the code works as intended. - Run the tests before making any changes, add tests to verify the changes, and ensure that the tests pass before considering the session complete.
35. # xcodebuild To save context, use the tool xcsift to format the output of xcodebuild or Swift. OVERVIEW: A Swift tool to parse and format xcodebuild output for coding agents xcsift reads xcodebuild output from stdin and outputs structured JSON. Important: Always use 2>&1 to redirect stderr to stdout. This ensures all compiler errors, warnings, and build output are captured. Examples: - xcodebuild build 2>&1 | xcsift -w - xcodebuild test 2>&1 | xcsift -w - swift build 2>&1 | xcsift -w - swift test 2>&1 | xcsift -w
36. # Structure hygiene Fix all errors, warnings, and failed tests, even if they are not related to the current changes being made.
37. # grep or search text You are operating in an environment where ast-grep is installed. For any code search that requires understanding of syntax or code structure, you should default to using ast-grep --lang [language] -p '<pattern>'. Adjust the --lang flag as needed for the specific programming language. Avoid using text-only search tools unless a plain-text search is explicitly requested.
38. # apple platforms tips Apple’s Essential Tips for iOS App Speed and Efficiency - Profile early and often using Instruments in Xcode 26. Identify bottlenecks in SwiftUI views and Foundation Model requests before you ship. - Optimise SwiftUI views by profiling view trees, caching expensive computations, and trimming main thread usage. Avoid repeated body - omputation to prevent dropped frames. - Streamline Foundation Model requests by reducing context payloads, removing redundant data, and keeping request windows small for faster - responses. - Make memory and algorithm improvements with Swift’s new InlineArray and Span types. Replace custom slow loops with built-in methods like - First(), and validate any speedups with flame graphs. - Accelerate app launch by deferring work not needed immediately. Move blocking network, file, and calculation calls off the main thread. - Minimise energy usage by using incremental updates instead of full reloads, and only fetching or displaying what users need right now. - Benchmark your changes and document optimisation decisions.
39. qrcodeapp-1-agents.mov
41. Let’s make a plan We are going to build a macOS app for QR generation with the following features: • A text field where the user can enter a value • A button to generate a QR code, disabled until the user has entered meaningful text • When the button is pressed, a QR code is generated and displayed • In the QR code view, options to: • Download the QR code as a PNG file • Generate another PNG for new input • A history of generated QR codes, persisted to a file • A sidebar that shows the history and displays a preview of the selected QR codeThe code must be written in Swift and SwiftUI.
42. qrcodeapp-2-plan.mov
43. Let’s implement it qrcodeapp-3-implementation.mov
44. Let’s run it qrcodeapp-4- fi rst run.mov
45. Let’s fi x it qrcodeapp-5- fi x-bug.mov
46. Now it’s your turn • Clone https://github.com/gscalzo/QRCodeApp • Add https://github.com/dagronf/QRCode as dependency • Implement fancier QRCode layouts
47. Let’s do a more complex app
48. Let’s do a more complex app: Split Bill
50. Let’s do a more complex app: Split Bill
51. Requirements 👥 Create a group of participants for the event.
52. 🧾 Decode a picture of a receipt and extract the items. 👥 Create a group of participants for the event. Requirements
53. Requirements 🧾 Decode a picture of a receipt and extract the items. 👥 Create a group of participants for the event. 🧮 Implement a receipt breakdown to assign items to participants.
54. Requirements 🧾 Decode a picture of a receipt and extract the items. 👥 Create a group of participants for the event. 🧮 Implement a receipt breakdown to assign items to participants. 💸 Present a f inal breakdown of the costs for each participant.
55. 🧾 Decode a picture of a receipt and extract the items. 👥 Create a group of participants for the event. 🧮 Implement a receipt breakdown to assign items to participants. 💸 Present a f inal breakdown of the costs for each participant. 💾 Save the event locally for future reference. Requirements
57. FAgents.md A few agents, some in parallel
58. FAgents.md Implementation with Mocked OCR A few agents, some in parallel
59. Icon and Splash Screen FAgents.md Implementation with Mocked OCR A few agents, some in parallel
60. splitbill-3-icon.mov
61. Icon and Splash Screen FAgents.md Implementation with Mocked OCR OpenAI OCR General Tweaks A few agents, some in parallel
62. splitbill-4-app
63. • September 2010 • H a ndm a de, endless cr a shes • 3 weeks of development • Asynchronous meetings with st a keholders: they were never h a ppy. The Original Split Bill
64. • M a y 2025 • Used Firebender, Cursor, Sonnet 3.7 • ~ 1 d a y of development • Problems with initi a l setup, connection with OpenAI The Londroid Split Bill
65. • July 2025 • Used Copilot for Xcode, Sonnet 3.7 • ~ 1 d a y of development • Problems with connection with OpenAI, n a vig a tion The NewDay Show&Tell Split Bill
66. • November 2025 • Used Antigr a vity, Gemini 3 • ~ 1 hour of development • Minor l a yout problems, some twe a ks were necess a ry for the connection with OpenAI The NSLondon Split Bill
69. @thekitze
71. AI Accelerated Development
72. Thank you Thank you Thank you Thank you Thank you
73. References https://github.com/gsc a lzo/SplitBill-Londroid https://github.com/gsc a lzo/SplitBill-NSLondon https:// a gents.md/ https://github.com/ldom a r a dzki/xcsift https:// a st-grep.github.io/ https://x.com/kier a nkl a a ssen/st a tus/1938453871086682232 https://x.com/thekitze/st a tus/1974806037963166077 https://x.com/steipete/st a tus/1979960766670209200 https://www.cnbc.com/2025/05/28/nvidi a -ceo-jensen-hu a ng-youll-lose-your-job-to-somebody-who- uses- a i.html Videos https://youtu.be/TECDj4JUx7o (YC - How Agents will ch a nge our job) https://youtu.be/muh8ooHd7yU (Peter Steinberger) https://youtu.be/BJjsfNO5JTo (Tom Blom f ield - Get the best Out of Vibe Coding) https://www.youtube.com/@ a iexpl a ined-o ff ici a l https://www.youtube.com/@AID a ilyBrief https://tinyurl.com/4 a z4t6mh (AIN a tiveDevCon)