FYI, be careful!

«In iOS 15 and later, the system may, depending on device conditions, prewarm your app — launch nonrunning application processes to reduce the amount of time the user waits before the app is usable. Prewarming executes an app’s launch sequence up until, but not including, when main() calls UIApplicationMain. This provides the system with an opportunity to build and cache any low-level structures it requires in anticipation of a full launch.

If your app executes code before the call to UIApplicationMain, such as in static initializers like load(), don’t make assumptions about what services and resources are available. For example, keychain items may be unavailable because their data protection policies require an unlocked device and prewarming happens even when the device is in a locked state.»

UPD
Seems like a bug, but application(_:didFinishLaunchingWithOptions:) is invoked as well during a prewarning. I've sent a link to a thread in the comments. 🤔

https://developer.apple.com/documentation/uikit/app_and_environment/responding_to_the_launch_of_your_app/about_the_app_launch_sequence?language=objc#3894431
#iOS

If you are looking forward to adopting new concurrence features in Xcode 13.2, don’t install Xcode from AppStore.

To workaround this issue, please re-download Xcode 13.2 directly from Releases section.

https://developer.apple.com/forums/thread/696504?page=1
#Xcode

Apparently only I've not written about the new Swift Playground for iPads yet...

TL;DR

- Yes, you can now build SwiftUI apps right on your iPad.
- Yes, you can use also UIKit if you prefer.
- Yes, you can ship your apps to the App Store straight from your iPad.
- Yes, it supports Swift Package Manager packages from GitHub.
- Yes, you get the fantastic new code completion, just like with Xcode.
- Yes, it ships with Swift 5.5 and all the concurrency awesomeness that entails.

https://www.hackingwithswift.com/articles/244/swift-playgrounds-4
#iPad #swift_playground

Apple’s use of Swift and SwiftUI in iOS 15.
https://blog.timac.org/2021/1219-state-of-swift-and-swiftui-ios15/
#statistics #iOS

Oh, looks like a great Christmas present! 🎅
https://forums.swift.org/t/introducing-swift-for-visual-studio-code/54246
#swift #visual_studio

🎄 Best wishes to the coming year! 🎄

May your code always compile on the first try, found bugs are features actually and all projects start with iOS 15.

🎉🎉🎉

By the way, I'm not sure it'd be interesting to all of you, but if you have your own domain or are just curious about DNS records, there's a great site to play with.

The guys at pointfreeco have done an amazing investigation for triggering custom Xcode warnings at runtime using os_log.

p.s. Don’t try this at Home Release

https://www.pointfree.co/blog/posts/70-unobtrusive-runtime-warnings-for-libraries
#Xcode

Oh, what a surprise!

“Use switches in table rows only. Switches are intended for use in tables, such as in a list of settings that can be toggled on and off. If you need similar functionality in a toolbar or navigation bar, use a button instead, and provide two distinct icons that communicate the states.”

🧵with details: https://twitter.com/featherless/status/1477294898718154752?s=21

#iOS #HIG

Great summary of the most annoying Swift Playground limitations at the moment. But what the name implies - it's a playground, not Xcode on iPad yet.
https://www.cephalopod.studio/blog/lessons-from-developing-an-app-on-the-ipad-from-start-to-finish-on-the-app-store
#swift_playground

If you're still maintaining a legacy codebase with a lot of Objective-C code - worth reading this migration guide by far.
https://www.steveonstuff.com/2022/01/13/migrating-from-objc-to-swift.html
#swift #objc

Apple released several tech talks:

- custom product page with its optimization
- some tips from the App Review team for avoiding common review issues
- how apps can use CloudKit to share records with others
- best practices with StoreKit 2 and App Store Server API
- and more...

https://developer.apple.com/news/?id=c63z27o8
#apple

Apple now lets developers configure custom offer codes in App Store Connect.

Offer codes can be used in a variety of ways:
- Send an email sharing the latest features and recently added content with an offer code to current or lapsed subscribers, so they can experience your service for a limited time.
- Distribute flyers that include custom codes to promote your service to event attendees.
- Partner with another company on a marketing initiative or referral campaign to help promote your app.
- Provide a code to a subscriber with a customer service issue to compensate for the issue and encourage retention.
- Distribute one-time-use codes within an app that you’re sunsetting as a way to transition current subscribers to your new app and promote your service.

https://developer.apple.com/news/?id=9sjl5wuv
#Apple #subscriptions

Haven't posted for a while something interesting about build time optimization, so here it is.

The article describes the various aspects:
- collecting the build data from developer machines by XCLogParser
- analyzing the compilation process using Swift compiler flags
- getting and interpreting build.trace files by using New Build System tricks
- and of course, the possible solutions

https://medium.com/gojekengineering/reducing-our-build-time-by-50-835b54c99588
#Xcode #optimization

Oh, looks like worth mentioning - Apple's unofficial localization glossary. It will be very helpful to those who want to replicate the localization behavior for their own applications.
https://applelocalization.com
#Apple #localization

Apple finally released unlisted apps that are discoverable only with a direct link. These apps don’t appear in any App Store categories, recommendations, charts, search results, or other listings.
https://developer.apple.com/support/unlisted-app-distribution/
#Apple #AppStore

Github Action is a super simple CI system to integrate and maintain. It's very attractive to indie developers and small organizations due to its decent price as well (2000 free minutes per month). So an author enjoying this tool decided to dive into some tips and tweaks to make the most of it.
https://benoitpasquier.com/tips-tweaks-github-action-ios/
#CI #github_action

Precise calculation? Should you use Double or Decimal? It really depends. So Jesse asked the community in twitter to figure it out.
https://www.jessesquires.com/blog/2022/02/01/decimal-vs-double/
#Swift

Some of the SwiftUI modifiers are not really obvious to developers, so to comprehend them properly need to play around with it a bit. Jordan saved us some time and explained the behavior of the fixedSize modifier with a few useful examples.
https://www.swiftjectivec.com/swiftui-modifier-monday-fixedsize/
#SwiftUI