iOS - delegate pattern

iOS Delegate Pattern

Use the delegate pattern when an object needs to communicate with its owner in a decoupled manner.
delegate an object that executes a group of methods on behalf of another object
protocol is a list of methods that a delegate must implement
- any object that fulfills the protocol can become the delegate
View
- The object that will have the delegate
ViewController
- Can implement the delegate or another class can

Examples of Protocols

Climbing Communication Protocols When Belaying
- American Alpine Club

ClimberBelayer Protocol

public protocol ClimberBelayerProtocol: class {
    /**
    Implement this protocol method when climber is ready to start climbing
    */
    func onBelay()
    /**
    Implement this protocol method when climber is starting to climb
    */
    func climbing()
    
    /**
    Implement this protocol method when climber is about to fall
    */
    func falling()
}

ClimberBelayerDelegate

class ClimbingSession: ClimberBelayerProtocol {
    var climber: Climber?
    var belayer: Belayer?

    init() {
        climber = Climber(name: "Jess", weight: 115)
        belayer = Belayer(name: "Hannah", weight: 105)
        climber.climberBelayerDelegate = self
    }
    
    func onBelay() {
        print("Belay is on")
    }
    
    func climbing() {
        print("Climb on")
    }
    
    func falling() {
        print("I've got you")
    }
}

public class Climber {
    public var name: String?
    public var weight: Float?
    public weak var climberBelayerDelegate: ClimberBelayerProtocol?
    
    init(name: String, weight: Float) {
        self.name = name
        self.weight = weight
    }
    
}

public class Belayer {
    public var name: String?
    public var weight: Float?
    
    init(name: String, weight: Float) {
        self.name = name
        self.weight = weight
    }
}