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iOS Coding Cheatsheet

This cheatsheet preserves the original Swift and SwiftUI snippets and comments; only Markdown headings and code fences were added for readability.

Property Observer: sanitize value on change​

// Processing setting of a value

var email: String {
  didSet {
    guard email != oldValue {
      return
    }

    email = email.trimmingCharacters(in: .whitespacesAndNewlines)
  }
}

UserDefaults basics​

let defaults = UserDefaults.standard
defaults.set("value", forKey: "someKey")
defaults.synchronize()

if let value = defaults.string(forKey: "someKey") {
  // work with value
}

Text utilities​

"Some text".lowercased(),
"Some text".uppercased(),
// capitalize every word
"Some text".capitalized(),

Use UIKit view inside SwiftUI​

// To use UIKit in SwiftUI

struct MultiplierLabelView: some UIViewRepresentable {
   var text: String

   func makeUIView(context: Context) -> some UIView {
       MultiplierUILabel()
   }

   func updateUIView(_ uiView: MultiplierUILabel, context: Context) {
       uiView.text = text
   }
}

List all available fonts (App Delegate)​

// To get all available fonts to check names
// In App Delegate
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

    UIFont.familyNames.forEach({ name in
        for font_name in UIFont.fontNames(forFamilyName: name) {
            print("\n\(font_name)")
        }
    })

    return true
}

Debug view updates​

// To debug views

struct SomeView: View {
  let _ = Self._printChanges()

  var body: some View {
    Text("Hello")
  }
}