Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

iOS Protocols in Swift Protocol Basics Protocols With Methods

Dmitry Vashlaev
Dmitry Vashlaev
2,715 Points

Protocols

Hello, I have some troubles with this code. It seems to be ok but it's not working. Any ideas?

protocols.swift
// Declare protocol here
protocol ColorSwitchable {
  func switchColor(color: Color)
}

enum LightState {
  case on, off
}

enum Color {
  case rgb(Double, Double, Double, Double)
  case hsb(Double, Double, Double, Double)
}

class WifiLamp {
  let state: LightState
  var color: Color

  init() {
    self.state = .on
    self.color = .rgb(0,0,0,0)
  }
}

1 Answer

Lucian Rotari
Lucian Rotari
12,007 Points

Hi Dimitry, you have got all right but you just missed one important thing.

Just read this sentence careful

For the sake of this challenge, make sure your external argument label is omitted by using an underscore.

I just copied and paste your code snipped and added a underscore for external argument.

So your code must look like that:

protocol ColorSwitchable {
  func switchColor( _ color: Color)
}

But I found this on apple guides

As with type property requirements, you always prefix type method requirements with the static keyword when they’re defined in a protocol.

However it works without 'static' as well.

Dmitry Vashlaev
Dmitry Vashlaev
2,715 Points

I didn't get the task right, thank you for help.

Lucian Rotari
Lucian Rotari
12,007 Points

You can read more about this on Apple documentation or “The swift programing language” provided by Apple