A tip for optimising speed for your Swift and Objective-C code — Creating a new collection type occupies resources. Frequently creating collection type objects, for example, initialising a dictionary in a for-loop or in a function that is frequently executed, might consume a considerable amount of time. In the following examples, I use reduce(_:_:) and reduce(into:_:) to demonstrate the differences in execution…

A step-by-step tutorial on how to automate CI pipeline for an iOS app on GitHub — Prerequisites A scheme named CI has been created to define the tests to execute during continuous integration. When changes are merged to master, these tests will be triggered to detect any errors immediately. If you haven’t created one for your continuous integration, please do it first.

A string created from NSLocalizedString is an instance of _NSBPlistMappedString, which might cause an incorrect result of comparing 2 strings — There are 2 strings: one is created from NSLocalizedStringand the other is passed from Swift. The result of comparing if 2 strings are equal is supposed to be YES, but it turns out to be NO. BOOL isEqual = [swiftString isEqualToString: localizedString]; It is because, in iOS 16, a string…

It’s Apple’s design that only when the cell height is equal to or bigger than 90, both image and title will show on the swipe action. There are 3 ways to show both. — The following code sets the action title to “Caught” and sets the image to a system star icon. let starAction = UIContextualAction(style: .normal, title: “Caught”) { _, _, _ in } let starImage = UIImage(systemName: “star.fill”) starAction.image = starImage

If you get an error “<your project path> building for iOS Simulator, but linking in an object file built for iOS, file <your project path> for architecture arm64”, you need to open it using Rosetta — This error message shows when you try to run iOS stimulators on M1 Mac.

A step-by-step tutorial for the beginners of git — I found that the biggest barrier that hinders me from learning git is git editor, and I believe lots of people are struggling to learn git like I used to be. You can find tons of articles that teach you how to combine two commits on the internet, but none…

textLabel, detailTextLabel, and imageView are deprecated in iOS 14. Now we should use configurations for our cells and views. — We used to set the content and styling of the image and text on a cell directly before UIListContentConfiguration was introduced in WWDC20. You must be familiar with these lines of code. This is how we customised the built-in imageView and textLabel of a UITableViewCell.

The simplest way to make collection view cells with dynamic width or height — Self-sizing cells are widely used in my projects. It took me hours to google the solution when I was a beginner in iOS development. Creating self-sizing cells are actually very simple. …