BMView

public protocol BMView : AnyObject

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