Learn iOS development with Swift

Learn iOS development with Swift

Shortcuts (that i use frequently)

Key	Description
`Command + 0`	Toggle navigator panel
`Command + Option + 0`	Toggle inspector panel
`Command + Shift + L`	Open object library
`Command + D`	Duplicate object
`Command + Option + Enter`	Toggle preview panel
`Control + I`	Format code
`Option + Click`	Open document

Learning Logs

16 Mar 2022

Learn how to use playgrounds.
Learn about variables in Swift that have two types: let for immutable and var for mutable.

Learn about optionals in Swift and how to unwrap using if let.

var name: String? // This is an optional string.

if let name = name { // Unwrap the optional to ensure it has a value.
  print("Hello, \(name)")
}

Use backslash for escaping characters.

let name = "John"
print("Hello, \(name)") // Hello, John

Learn about UIView and UILabel and how to display labels in a view.

UIView

let orangeBox = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
orangeBox.backgroundColor = .orange

UILabel

let goodbyeMessage = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
goodbyeMessage.text = "Byeeeee"

20 Mar 2022

Connect button to function by Control + click button in storyboard and drag to the function with @IBAction keyword in swift file.
To get button's text, use button.titleLabel?.text.
viewDidLoad function is called when the view is loaded.
Open document by holding Option key and click on variables, functions.
Center the button using autolayout by adding Horizontal in Center and Vertical in Center constraints.
Update misplaced view by selecting yellow arrow in document outline and update the view's frame.
To open preview, press Command + Option + Enter.
To hide/show left sidebar, press Command + 0 and right sidebar, press Command + Option + 0.

22 Mar 2022

To create spacing constraints, Click Add New Constraints or Control + drag object to the view.
To edit constraints, Double click on the blue line or edit the constraint's value in the attribute inspector panel.

27 Mar 2022

Learn how to embed objects in a stack view
- By adding stack view from object library.
- By select multiple objects and select "Embed In".
Edit alignment, distribution, spacing of stack view via inspector panel
Autoshrink label for small screen by edit "Autoshrink" value in inspector panel.
To add images, select "Assets" in project navigator and drag image to set viewer.

13 Apr 2022

Adjust the size of objects for specific screen using size classes.
- iOS devices have two size classes for width and height that can be either regular or compact.
- By clicking on + button in the inspector panel, you can add size classes to that property.
Testing dark mode by clicking on Environment Overrides and select dark mode in Apperance section.
Learn how to use UITableViewController.

Use @IBOutlet to connect objects in storyboard.

@IBOutlet var nameLabel: UILabel!
@IBOutlet var locationLabel: UILabel!
@IBOutlet var typeLabel: UILabel!
@IBOutlet var thumbnailImageView: UIImageView!

14 Apr 2022

Learn to create action sheet using UIAlertController and UIAlertAction.

let optionMenu = UIAlertController(title: nil, message: "What do you want to do?", preferredStyle: .actionSheet)
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel)

optionMenu.addAction(cancelAction)

present(optionMenu, animated: true)

Use .actionSheet to create action sheet and .alert to create alert dialiog.

Learn closure syntax.

let reserveActionHandler = { (action:UIAlertAction!) -> Void in
  // Body of the closure.
}

Cell in table view is reusable cell then some state may be persist when it's reused again.

18 Apr 2022

Learn how to cast objects by using as!

let cell = tableView.cellForRow(at: indexPath) as! RestaurantTableViewCell

To hide/show UIImageView by setting its isHidden property.

Create object by using struct and initializer by creating init function(s).

struct Restaurant {
  var name: String
  var type: String
  var location: String
  var image: String
  var isFavorite: Bool
  
  init(name: String, type: String, location: String, image: String, isFavorite: Bool) {
      self.name = name
      self.type = type
      self.location = location
      self.image = image
      self.isFavorite = isFavorite
  }

  init() {
      self.init(name: "", type: "", location: "", image: "", isFavorite: false)
  }
}

Struct can have multiple initializers.

Create instance of struct without new keyword.

Restaurant(name: "Traif", type: "American", location: "New York", image: "traif", isFavorite: false)

aofleejay / learn-ios