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iOS Build a Simple iPhone App with Swift 2.0 Improving Our User Interface Changing the Background Color

Piers FC
Piers FC
10,402 Points
Posted by Piers FC
Piers FC
10,402 Points

Another poor question - I can't understand from the compiler errors what I am doing wrong - swift 2.0 changing

Let's get some practice working with views and colors! In the editor below you have a view controller subclass.

Add a stored property to the view controller named blueColor and assign an instance of UIColor as the default value.

You can use UIColor's RGB initializer method and pass the values 0,0,255,1.0 for red, green, blue and alpha respectively. Alternatively, UIColor has a convenience method that you can use: UIColor.blueColor().

This is my answer, I have tried several different ones

class ViewController: UIController { /* declaring the stored property with an Instance of UIColor as the default value using the convenience method */ let blueColor = UIColor.blueColor()

override func viewDidLoad() {
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    // Dispose of any resources that can be recreated
}

}

I then get this error

swift_lint.swift:48:23: error: use of undeclared type 'UIController' class ViewController: UIController { ^~~~~~~~~~~~ swift_lint.swift:52:19: error: method does not override any method from its superclass override func viewDidLoad() { ~~~~~~~~ ^ swift_lint.swift:56:19: error: method does not override any method from its superclass override func didReceiveMemoryWarning() {

Any idea why Treehouse can become so frustrating / what is the solution to this problem?

colors.swift 
class ViewController: UIController {

    override func viewDidLoad() {
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        // Dispose of any resources that can be recreated
    }

    let blueColor = UIColor()
    view.backgroundColor = blueColor(red: 0, green: 0, blue: 255, alpha: 1.0)
}
Martin Granger
Martin Granger
14,521 Points

Unfortunately, I noticed a typo in the challenge code. "UIController" should be "UIViewController". I tried

class ViewController: UIViewController {
  let blueColor = UIColor(red: 0, green: 0, blue: 255, alpha: 1.0)

    override func viewDidLoad() {
        // Do any additional setup after loading the view, typically from a nib.
        view.backgroundColor = blueColor

    }

    override func didReceiveMemoryWarning() {
        // Dispose of any resources that can be recreated
    }
}

4 Answers

Chase Marchione
Chase Marchione
155,055 Points
Chase Marchione
Chase Marchione
155,055 Points

Hi Piers FC, and Martin,

What got me through the first challenge was declaring and initializing blueColor by using the RGB initializer method and passing in the provided values that resemble a blue color. Then for the second challenge, I stored the statement that changes the view's backgroundColor within the viewDidLoad method (which is where properties of the view or view controller object get initialized.)

class ViewController: UIViewController {

    let blueColor = UIColor(red: 0, green: 0, blue: 255, alpha: 1.0)

    override func viewDidLoad() {
        // Do any additional setup after loading the view, typically from a nib.
        view.backgroundColor = blueColor
    }

    override func didReceiveMemoryWarning() {
        // Dispose of any resources that can be recreated
    }

}

Hope this helps!

Asma Al-Marrikhi
Asma Al-Marrikhi
45,525 Points
Asma Al-Marrikhi
Asma Al-Marrikhi
45,525 Points 
class ViewController: UIViewController {
let blueColor = UIColor.blue
  override func viewDidLoad() {
      super.viewDidLoad()
      // Do any additional setup after loading the view, typically from a nib.

 }

  override func didReceiveMemoryWarning() {
      super.didReceiveMemoryWarning()
      // Dispose of any resources that can be recreated.
  }
}
Martin Granger
Martin Granger
14,521 Points
Martin Granger
Martin Granger
14,521 Points

Unfortunately, I noticed a typo in the challenge code. "UIController" should be "UIViewController". I tried

class ViewController: UIViewController {
  let blueColor = UIColor(red: 0, green: 0, blue: 255, alpha: 1.0)

    override func viewDidLoad() {
        // Do any additional setup after loading the view, typically from a nib.
        view.backgroundColor = blueColor

    }

    override func didReceiveMemoryWarning() {
        // Dispose of any resources that can be recreated
    }
}
Piers FC
Piers FC
10,402 Points
Piers FC
Piers FC
10,402 Points

Hi Guys

Thanks for the help and explanations. I can see where I was going wrong CJ, so thanks. I was trying to do both in the first challenge as well, which didn't help.

I have another question on AutoLayout which would be great if you could look at.

Cheers