Protocols

A protocol that views should conform to.

Its main goal is to help structure the code in a more clean, organized way.

Example

/// An image based checkbox.
open class SKCheckbox: UIControl, BMView {

  // MARK: - Properties

  /// The currently displayed checkbox Image.
  private var checkboxImage = UIImageView()

  /// Overriding the original method to update the icon based on state.
  open override var isEnabled: Bool {
    didSet { self.update() }
  }

  // MARK: - Interactions

  public var valueDidChange: ((_ checkbox: SKCheckbox, _ oldValue: Bool) -> Void)?

  // MARK: - init

  /// `init` via code.
  public override init(frame: CGRect) {
    super.init(frame: frame)
    self.configure()
    self.update()
    self.layout()
  }

  /// `init` via IB.
  public required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    self.configure()
    self.update()
    self.layout()
  }

  // MARK: - CSUL

  public func configure() {
    self.addSubview(self.checkboxImage)
  }

  public func style() {
    // style the default looks of the view and its subviews.
  }

  public func update() {
    // update UI when isEnabled changes status, among other things.
  }

  public func layout() {
    // layout the `checkboxImage` and other potential subviews.
  }
}

The view exposes properties and interactions to the outside world. The properties deal with the state of the element, whereas the interactions are callbacks to interact with changes inside the element. The lifecycle of the view is composed of configure, style, update andlayout`.

Configure

Executed once when the view is instatiated. It deals with configuring the view. For instance, a typical usecase would be to add subviews, or setup interactions.

func configure() {
  self.addSubiew(sel.checkboxImage)
}

Style

Executed once when the view is instatiated. It deals with applaying the basic static styling to the view. In other words element properties that are independent of the state of the element are applied here. If the background of the element always has the same color, the background color is set here.

func style() {
  self.backgroundColor = .white
}

Update

Update is not directly called when the object is instantiated but rather when a state related value changes its state. Inside of the update, changes should be made to the UI to reflect the new state.

  open override var isEnabled: Bool {
    didSet { self.update() }
  }

Layout

Excecuted once when the view is instatiated. It layouts the subviews as intended.

func layout() {
 self.checkboxImage.frame = self.bounds

See more

public protocol BMView : AnyObject

An object, preferably a struct, containing a set of properties to be passed to a BMViewWithViewModel. These properties should help the view render itself to reflect proper states.

struct ProfileViewModel: BMViewModel {
  let name: String
  let age: Int = 27
}

public protocol BMViewModel

A BMViewWithViewControllerAndViewModel is a BMViewWithViewModel view managed by a UIViewController. This “managing” automatically calls the configure, style and layout phases. In addition, the controller set the viewModel of the view, therefore invoking the update at least once before the view is actually displayed. This view is extended with helpers allowing to access the UINavigationBar, UINavigationItem, UIViewController from the view when present.

See more

public protocol BMViewWithViewControllerAndViewModel : BMViewWithViewModel

A BMViewWithViewModel takes the BMView and UIView a step further by introducing a view model. The view model is an object containing a set of properties reflecting the state of the view. A view model makes it easier to mock a view by passing the state from the outside and therefore test it in any desired state.

Example

struct ProfileViewModel: BMViewModel {
  let name: String
  let age: Int

  var isAdult: Bool {
    age > 18
  }

  var badgeColor: UIColor {
    isAdult ? .green : .red
  }
}

class ProfileView: BMViewWithViewModel {
  let badge = UIView()
  let nameLabel = UILabel()

  func configure() {
    self.addSubview(self.badge)
    self.addSubview(self.nameLabel)
  }

  func style() {
    // style the elements
  }

  func update(oldViewModel: ProfileViewModel?) {
    self.badge.backgroundColor = self.viewModel?.badgeColor
    self.nameLabel.text = self.viewModel?.name
  }

  func layout() {
    // layout the subviews
  }
}

By conformimng to BMViewWithViewModel in this previous example, we notice we do not explicetely need to specify the viewModel since it is infered by swift through the update(oldViewModel: VM?) method.

By altering the view model, different states of the view can be tested in a fast efficient way.

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public protocol BMViewWithViewModel : BMView

A protocol requiring its conformer to declare its UIViewController Hierarchy. Any custom UIViewController other than UINavigationController, UITabBarController containing a custom navigation should conform to this protocol.

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public protocol InspectableHierarchy : AnyObject

A protocol that only UIViewController should conform to to returnm the presentedViewController if present.

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public protocol InspectablePresentedViewController : AnyObject

A protocol that all navigable ViewControllers should adhere to. The UINavigationController and the UITabBarController should NOT adhere to this protocol.

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public protocol Routable : AnyObject

TypeErasure for RoutableObject<VM: BMViewModel>

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public protocol AnyRoutableObject

A configuration provider for the Router that the dependencies manager in the app should conform to. It requires the conformer to provide the screens and their respective view controller.

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public protocol RoutingConfigurationProvider