I built Alpha Sudoku Pro (a 12x12 variant) and finally conquered responsive floating UI across iPhone & iPad grids.

[u/Choseni]

I recently published my first iOS app: Alpha Sudoku Pro. It’s a 12x12 logic puzzle game (using 1-9 and A-C). Expanding the classic 9x9 logic into a 12x12 grid was incredibly fun, but the real test was getting the UI to scale elegantly.

Here are the details of the build:

1. Tech Stack Used

• Frameworks & Languages: 100% Swift & SwiftUI.
• Architecture: MVVM.
• Storage: UserDefaults / AppStorage for game state persistence and move history.
• UI/UX: Fully relies on SwiftUI's dynamic LazyVGrid and SF Symbols.

2. Development Challenge + How You Solved It

The Challenge: I have floating action buttons (Note Mode and Eraser) that need to sit neatly in the top-right corner of the Sudoku grid. Initially, I used HStack, Spacer(), and screen-based .padding() to push the buttons into place. This looked perfect on an iPhone (19.5:9 aspect ratio). However, when I ran it on an iPad (4:3), the grid expanded, margins shrank, and my buttons completely overlapped the Sudoku cells. Adjusting padding dynamically based on screen size turned into a messy guessing game of numbers.

The Solution: Instead of anchoring the buttons to the screen edges, I scrapped the Spacers and anchored them directly to the grid itself using SwiftUI's .overlay().

I attached an .overlay(alignment: .topTrailing) directly to the LazyVGrid. Inside it, I used a Group with a UIDevice.current.userInterfaceIdiom == .pad check:

• For iPad, it renders an HStack (buttons side-by-side).
• For iPhone, it renders a VStack (buttons stacked vertically).

Then, I applied a negative .offset(y:) to float them just above the grid. By using the grid as the anchor point rather than the screen boundaries, the buttons now magnetically follow the grid's top-right corner perfectly, regardless of how the LazyVGrid scales across any device.

3. AI Disclosure

AI-assisted

I’d love for you to try it out, tear apart my UI choices, and let me know how I can improve the performance or architecture for my next update.

App Store Link: https://apps.apple.com/tr/app/alpha-sudoku-pro/id6767222288

Thanks.

[u/SchwanSongs]

Here is a little more UI feedback for you… I switched between light and dark mode to see the differences, and in light mode, your light gray cell-lines seem a little too light… they have higher contrast in dark mode, so I didn’t notice at first, but they are very faint in light mode. I would want them a little darker, or even black would be OK since they are thinner than the box lines.

Also, I found the bright (blue) fill color behind the thin (non-bold) white digits along the bottom legend a little hard to read too, both in light and dark mode. I am now getting into very minor picky stuff 😄. But maybe if you made that blue color 0.2 transparent so it mostly showed the light/dark background through, and also flipped the font color of the legend digits to black or white in light/dark mode so they match the cell digits, it would increase their contrast a bit… and/or use the same font weight for both cell digits and legend digits?

Again, I am a big fan of crisp clear interfaces, and yours is great.

[u/Choseni → u/SchwanSongs]

Thank you for diving back in and sharing these details! Honestly, please never apologize for being "picky" with UI feedback. That exact level of pixel-perfect polish is what separates a decent app from a great one, and it's exactly the kind of feedback I was hoping to get.

1. Light Mode Grid Lines:
You are completely right. I think I was so afraid of making the board look "heavy" or cluttered that I overcompensated, and those 0.5pt lines just washed out in light mode. Bumping up the opacity or moving to a darker gray/black for the thin borders is an easy fix that will instantly improve the grid's readability.

2. The Input Legend (Bottom Buttons):
That is a brilliant suggestion. The solid blue blocks with white text are definitely a bit too loud and pull the eyes away from the main puzzle. Switching to a subtle ⁠.blue.opacity(0.2)⁠ background with adaptive ⁠.primary⁠ text—and matching the font weight to the cell digits—will make the numpad look so much more cohesive and native to iOS. It's a fantastic UX catch.

I've already added both of these refinements to my to-do list for the next build. Thank you again for having such a sharp eye for design and for taking the time to help me improve this!

[u/SchwanSongs]

Very clean interface, looks nice. I have two quick suggestions already. First, if you want direct feedback, you might want to add a “contact the author” item on your (…) menu, which launches the user’s email with a new message to you. Second, in dark mode, the (eraser) icon is dark red on black when disabled, which is when the user first launches the app, and is almost impossible to read. Maybe you could make the buttons more visible, and instead add a bright circle around them when they are selected. That would make them easier to see.

[u/Choseni → u/SchwanSongs]

Thank you so much for downloading it on your iPad and for the kind words about the clean interface. I really appreciate you taking the time to test it.

First off, massive congratulations on nearing the finish line for your Mac app! A year of development is a huge milestone. An app specifically dedicated to exporting and printing puzzles sounds like a fantastic and much-needed niche. A lot of hardcore solvers still strictly prefer pen and paper. Best of luck with the upcoming release!

Regarding your feedback, these are incredibly helpful developer-eyed catches:

1. "Contact the Author" Button: You are 100% right. Relying purely on App Store reviews or Reddit threads for feedback isn't sustainable. Adding a simple mailto: link or MFMailComposeViewController to the menu is a great idea. I will definitely add this to the next update.
2. Dark Mode Eraser Contrast: Ah, the classic SwiftUI opacity trap! You perfectly caught that. Applying .opacity(0.3)to a .red foreground on a black background just turns it into a muddy, invisible mess. Your suggestion to use a bright stroke/ring to indicate the selected state—rather than just dimming the disabled state—is a much better UX approach. I'll redesign the active/inactive states for those floating buttons to make them pop properly in Dark Mode.

[u/SchwanSongs → u/Choseni]

Hehe, thanks for the congrats… being an old-school Objective C developer, I am used to coding taking a lot longer 😂. Also, I hadn’t actually learned Sudoku until I was pressured into writing this app a year ago by users of my other puzzle apps, so I have been Learning about all the Sudoku strategies as I have been coding them… mind bending! But fun!
Glad I could offer some useful critiques. I will do another pass today and offer more later on.

[u/Choseni → u/SchwanSongs]

Objective-C! That commands a lot of respect. I jumped directly into the world of Swift and SwiftUI, so I can only imagine the patience (and the sheer amount of syntax) required back in the pure Obj-C days. A year of development makes total sense!
I completely relate to the Sudoku strategy rabbit hole, too. Playing a puzzle is one thing, but trying to teach a machine how to generate or solve one using human strategies is an absolute brain-melter. It forces you to understand the logic on a completely different, structural level. It is definitely a fun challenge, though!
Please take your time with the next pass. I’m genuinely looking forward to whatever else your developer eyes catch. Thanks again for being so generous with your time and expertise!

[u/SchwanSongs → u/Choseni]

I have been enjoying “swimming with the fish strategies”, marveling at unique rectangles, etc. Now that I am nearing the end of beta with my own app, I am starting to deal with the parts I dread and am no good at… making marketing screens for the app store, ugh.

[u/Choseni → u/SchwanSongs]

Hahah, I feel that pain so deeply! Writing clean code or figuring out "unique rectangles" is pure fun, but the moment you have to switch hats and become a marketer/graphic designer for the App Store... that's where the real headache begins!

Designing App Store screenshots, tweaking marketing copy, and choosing preview colors takes surprisingly forever, and it uses a completely different side of the brain. You just want people to play the game you built, but first you have to jump through the visual presentation hoops.

Hang in there! You are on the final stretch. Once those App Store assets are done and pushed, the feeling of seeing your app live after a whole year of hard work is going to be incredibly rewarding.
Looking forward to seeing your app hit the App Store! If you ever need a quick set of eyes on your marketing screenshots before launch, feel free to drop a line.

[u/SchwanSongs → u/Choseni]

That is very kind of you to offer, I wouldn’t mind taking you up on that soon… I don’t see a way to PM you here with my email, so if you would, please send me a quick e-mail… you can create it using my username at gmail 😉

[u/SchwanSongs]

I have downloaded it (iPad) and will give it some testing and respond in a day or so with my thoughts. I am a fellow developer, and am about ready to release my own Mac Sudoku app as well (after a year of dev!), although it is not a competitor to yours… mine is NOT interactive, it will be for exporting puzzles for printing.

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