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 Intermediate Swift Properties Property Observers

Sam Belcher
Sam Belcher
3,719 Points

I am confused. I have watched the videos over and over again and I still don't understand

also... Do you guys have any tips on code challenges in general? I feel like they have been becoming increasingly more dificult and its hard to keep up :/

observer.swift
class TemperatureController: UIViewController {
    var temperature: Double {
      didSet {
        switch self {
        case self > 80: view.backgroundColor = .red
        case self < 30: view.backgroundColor = .blue
        default: view.backgroundColor = .green
        }
      }
    }

    init(temperature: Double) {
        self.temperature = temperature
        super.init()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
    }
}

1 Answer

Hi there,

You are switching on self - that's the UIViewController instance. Switch on self.temperature.

Then for your case statements, I'd use a local constant. Something like:

case let x where x < 40 : view.backgroundColor = .blue

I hope that helps,

Steve.