Kein Li

SwiftUI view updates in @Observable vs @StateObject/@ObservedObject

Tue, 21 Jul 2026 00:00:00 +0000

Sort of a continuation from the previous post @StateObject vs @ObservedObject.

I’m used to using the modern @Observable macro over @StateObject/ObservedObject but when I came across Speecify’s iOS Debugging challenge, which had @StateObject/ObservedObject, it made me revisit how the @StateObject/ObservedObject differs from @Observable, and when SwiftUI decides to redraw the body.

I added print statements in the init of each child view along with the SwiftUI printChanges() in the body of each child view to see what actually runs.

SwiftUI differences in @StateObject vs @ObservedObject

Mon, 20 Jul 2026 00:00:00 +0000

I’m used to using the modern @Observable macro over @StateObject/ObservedObject but when I came across Speecify’s iOS Debugging challenge, which had @StateObject/ObservedObject, I was curious when to use each, how the @StateObject/ObservedObject differs from each other.

Starting with @StateObject/@ObservedObject: notice what happens if we initialize the view model inline and pass it to the child, where the child stores it via @ObservedObject. No issues when we increment the counter in the child and we see the update take effect.

Swift Fudamentals 1 - Structs v Classes

Mon, 15 Jun 2026 00:00:00 +0000

Explore differences between structs and classes and when to use each. Topics covered will include mutability, assignment, CoW.

class Foo {
 var count: Int 
 var bar: Bar?

 init(count:Int) {
 self.count = count 
 }

 deinit {
 print("i'm gone")
 }

 func printSelf() {
 print("my count: \(count)")
 }

 func printBarCount() {
 guard let bar else { return }
 print("bar count: \(bar.count)")
 }

 func mutateBar() {
 self.bar?.count+=1
 }
}

struct Bar {
 var count: Int 
 var foo: Foo? 

 func printFooCount() {
 guard let foo else { return }
 print("foo's count: \(foo.count)")
 }

 func mutateFooCount() {
 foo?.count+=1
 }
}

We’ll start with basics:

Building out DayMark - 0 to 1

Mon, 16 Mar 2026 00:00:00 +0000

Building Out DayMark App

https://apps.apple.com/us/app/daymark-daily-journal/id6760376611

Idea + Design

I found the easiest way to keep building any app or side project without abandoning it midway is to build something useful that you’ll actually use.

For me, I started writing down 1-3 sentences of what I did each day to ensure each day was somewhat productive. I believe small wins over a long period time add up and there will be an inflection point where you start seeing exponential growth. I used the notes app to do it but wanted a better UI with it.

Building out a mini iOS Manga App

Sun, 22 Feb 2026 00:00:00 +0000

Building Out a Mini iOS Manga App

Finally getting back into building iOS apps after a ~2 year hiatus. It’s been awhile since I built something outside of work. I started with watching some CS193P lectures and followed along for a few lectures before I got bored and decided the best way to learn is to build anything ASAP.

Personally I think using AI tools is awful when learning something new and having it write the code for you is awful. I use it strictly for learning purposes like “Explain Swift Concurrency” or “Is my code idiomatic?” or hints on how to approach a problem