Hacking with Swift

Trying out 100 Days of SwiftUI. This would probably be my 5th attempt for learning iOS/macOS development. 🤞 Hopefully I keep this up.

Day 10

2021/02/27

So, it’s been half a year. I am back. Remember how confused I was by everything on Day 9? I decided it’s time to get some help. I reached out to my friend @dlackty and got him to give me a 2 hour crash course for iOS development.

I feel a lot better now, even though I think I still can’t be productive yet. Let me just write down the things we covered in the 2 hours.

• Xcode UI walk through.

• Difference between Swift UI and storyboard. Swift UI is cool and new, but

  1. it won’t work on ~iOS 12 (~ iPhone 6)
  2. there are cross version compatibility issues between iOS 13 and 14
  3. limited 3rd party libraries

  It might not be a good idea to use it as of yet.

• You can also create UI by code, without the GUI, which is a popular approach. (Except, for the launch screen and the main screen, which you have to create with the GUI.)

• Think of *Controller files like HTML files, except you ignore best practices and write everything in the markup. People would obviously extract model code out, but the main point is— development starts from the page markup.

  <script>function () dostuff { ... }</script>
  <nav>
    <tab-container ontabchange="...">
      <button onclick="dostuff();"></button>
    </tab-container>
  </nav>
  

• To build an app version of a Rails webapp, you will likely end up with the same number of views/**/*.erb for *Controller.swift.

• npm -> cocoapods v.s. yarn(cache) -> carthage

• Core Data is for database, but you probably don’t and shouldn’t need it.

• Use playground to REPL stuff because you can’t be always compiling everything to test.

• RxSwift v.s. combine.

• For API needs, see Alamofire & Codable.

That’s about everything. But first, I will have to review the stuff from before (9 days lol) and re-learn the Swift syntax. BRB.

Day 9

2020/09/14

• Day 16 – Project 1, part one

I didn’t open my laptop at all for the weekend. ✌️ Hopefully I still remember how things work.

It did seem like I managed to build some UI, but I totally got turned around. The Picker example in the demo code doesn’t work, and turns out it was because SwiftUI expects the containing view to be inside a NavigationView. But why? and why didn’t Xcode tell me this? And why is this the case—

Closure containing control flow statement cannot be used with function builder ‘ViewBuilder’

Why can I only use the language’s forloop syntax in some cases and not all? why is ForEach different/significant? and why is PreviewProvider code a thing? I know what it’s for but it seems weird that it’s code that lives in your feature code solely meant for the IDE.

I don’t want to simply accept and memorize these. I want to understand them. :old_man_yells_at_cloud: I stopped at this point for the day.

On the plus side though, this time I was indeed less overwhelmed by Xcode.

Day 8

2020/09/10

• Day 15 – Swift review, day three

Nothing new. Gonna save day 16 for tomorrow since that’s when I’ll have to start to use Xcode.

Day 7

2020/09/09

• Day 13 – Swift review, day one
• Day 14 – Swift review, day two

I went through the topics through tests, and noticed that I missed fallthrough completely the first time around, probably because there wasn’t a code example for it.. so here’s the official doc for fallthrough. I like this a lot more for the explicitness.

Day 6

2020/09/08

• Day 12 – optionals, unwrapping, and typecasting

🤔🤔 Unwrapping 🤔🤔
Why create another variable just to check if a variable held value?
Why is func foo (number: Number?) { guard let number = number else { ... } } OK? Is variable shadowing not a thing?

Seems like ! is never a good idea when the result is crashing. try? is cool though.

Without actually writing the code every day I don’t feel like I’m memorizing the syntax.

Day 5

2020/09/07

• Day 10 – classes and inheritance
• Day 11 – protocols, extensions, and protocol extensions

🤔 I don’t think I’ve ever wanted something like final class.

protocols are like type definitions? except you can define protocol extensions which would actually give objects that conforms to those protocol methods and vars? and extensions defaults can be overriden without override––Turns out this was explained in the next part, POP (11/5).

extensions with mutatability wasn’t really explained but was tested. Specifically I thought Int being a class doesn’t need the mutating keyword when being extended in order to perform mutation, but it did?!

I haven’t watched any of the videos since they take much longer than reading.

Day 4

2020/09/06

• Day 5 – functions, parameters, and errors (revisited)
• Day 8 – structs, properties, and methods
• Day 9 – access control, static properties, and laziness

Tests for property observers seem wrong. The valid code samples have closures that don’t return anything.

Now googling for Swift REPL so I can write some stuff to remember them better ➡ Introduction to the Swift REPL.

Turns out I missed a few chapters for Day 5, specifically everything after 7. variadic functions 🤦🏻‍♀️ because variadic parameters were in the access control tests. I went back to read them today as well.

Day 3

2020/09/05

• Day 5 – functions, parameters, and errors
• Day 6 – closures part one
• Day 7 – closures part two

Trailing closure syntax isn’t confusing at all! Shorthand closure syntax isn’t confusing at all!!

Day 2

2020/09/04

• Day 3 – operators and conditions
• Day 4 – loops, loops, and more loops

repeat { ... } while ... is new to me.

Day 1

2020/09/03

• Day 1 – variables, simple data types, and string interpolation
• Day 2 – arrays, dictionaries, sets, and enums

Sure tuple can exist.