Protocols in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a protocol named Drivable.

iOS Swift

protocol [1] {
  func drive()
}

Drag options to blanks, or click blank then click option'

ADrivable

BDriveable

CDriving

DDrive

Attempts:

3 left

💡 Hint

Common Mistakes

Misspelling the protocol name.

Using a verb form instead of an adjective.

The protocol name should be Drivable to match the task requirement.

2fill in blank

medium

Complete the code to make the class Car conform to the Drivable protocol.

iOS Swift

class Car: [1] {
  func drive() {
    print("Driving the car")
  }
}

Drag options to blanks, or click blank then click option'

AVehicle

BDrivable

CDriveable

DRunnable

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong protocol name.

Forgetting to conform to the protocol.

The class must conform to the Drivable protocol to implement its requirements.

3fill in blank

hard

Fix the error in the protocol method declaration to make it optional.

iOS Swift

@objc protocol Drivable {
  [1] func drive()
}

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Aoptional

B@optional

C@objc optional

Doptional func

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'optional' keyword alone.

Missing the @objc attribute on the protocol.

In Swift, to make a protocol method optional, the protocol must be marked @objc and the method marked @objc optional.

4fill in blank

hard

Fill both blanks to declare a protocol Playable with a property and a method requirement.

iOS Swift

protocol Playable {
  var isPlaying: [1] { get set }
  func [2]()
}

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ABool

Bplay

CInt

Dstop

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong property type.

Using incorrect method name.

The property 'isPlaying' should be of type Bool, and the method name should be 'play' to match the protocol requirements.

5fill in blank

hard

Fill all three blanks to implement the Playable protocol in class MusicPlayer.

iOS Swift

class MusicPlayer: Playable {
  var isPlaying: [1] = false
  func [2]() {
    isPlaying = true
    print("Music started")
  }
  func [3]() {
    isPlaying = false
    print("Music stopped")
  }
}

Drag options to blanks, or click blank then click option'

ABool

Bplay

Cstop

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong property type.

Incorrect method names like 'start' instead of 'play'.

The property 'isPlaying' is Bool. The 'play' method fulfills the protocol requirement, and 'stop' is an additional method.