eMpTy Theory

Creating Custom Parseable Format Styles in iOS 15

Since way back in iOS 2.0, the venerable Formatter class and its derivations such as DateFormatter and NumberFormatter have been the go-to for converting values to and from strings. Over the years Apple has added other cool formatters such as the ByteCountFormatter, MeasurementFormatter, RelativeDateTimeFormatter, and ListFormatter. Now, as discussed in What’s New in Foundation atContinue reading “Creating Custom Parseable Format Styles in iOS 15”

Using iOS Diffable Data Sources with Different Object Types

Since iOS 13, we’ve been able to revamp the way our table and collection views work by using diffable data source classes (UITableViewDiffableDataSource and UICollectionViewDiffableDataSource respectively) and snapshots. This provides the advantage of being able to write less code for these types of views, while making our state management much more robust and less likelyContinue reading “Using iOS Diffable Data Sources with Different Object Types”

Identify Supported Images and Create Collections in SF Symbols 2

If you’ve been doing any sort of app development with iconography since iOS 13 came out, there’s a good chance you leveraged the original SF Symbols app. With around 1,600 scalable, vector-based symbols integrating with the system San Francisco font, along with guidance for creating your own symbols, it was ground-breaking in terms of providingContinue reading “Identify Supported Images and Create Collections in SF Symbols 2”

Better Uniform Type Identifiers with Xcode 12

If you’ve been doing any kind of file uploads, downloads, previews, and such in past versions of Xcode and needed to deal with MIME types or file extensions, you’ve probably had to deal with Uniform Type Identifers. Using CoreServices and some of its methods such as UTTypeCreatePreferredIdentifierForTag and UTTypeCopyPreferredTagWithClass could avoid some hard-coding of identifiersContinue reading “Better Uniform Type Identifiers with Xcode 12”

Use the new Xcode 11 Distribution Certificate Format

If you’ve ever distributed an app to the Apple App Store, you’ve probably generated an iOS Distribution certificate (either from Xcode or directly from the Apple Developer site. With Xcode 11, Apple released new Development and Distribution certificate types and has started using those by default. This was mentioned in the Xcode 11 release notes:Continue reading “Use the new Xcode 11 Distribution Certificate Format”

Nicely Formatted Lists with ListFormatter

Last time we took a look at the very useful RelativeDateTimeFormatter to create localized strings describing date differences programmatically. In this post we’ll look at a better way to handle presenting lists to your users. As programmers, it’s pretty common to have to take a list of objects (e.g. apples, bananas, oranges) and express theContinue reading “Nicely Formatted Lists with ListFormatter”

Using UITabBarAppearance for Tab Bar changes in iOS 13

With iOS 13, Apple finally made some long overdue changes to support more effective customizations of the tab bars, and tool bars in your apps. The new UITabBarAppearance, UIBarAppearance, and related classes lets developers easily modify not just the basics like background and selected colors but spacing, text attributes, badging, and positioning. Creating subtle effectsContinue reading “Using UITabBarAppearance for Tab Bar changes in iOS 13”


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