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

Ryan Maneo
Ryan Maneo
4,342 Points
Posted by Ryan Maneo
Ryan Maneo
4,342 Points

Hmm... what am I missing?

What am I missing here?

colors.swift 
class ViewController: UIViewController {

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

2 Answers

jcorum
jcorum
71,830 Points

Two problems. First, you code needs to be inside the viewDidLoad() method. Second, you need an object for the backgroundColor property, i.e., the view:

    override func viewDidLoad() {
        // Do any additional setup after loading the view, typically from a nib.
        let blueColor = UIColor(red: 0, green: 0, blue: 255, alpha: 1.0)
        view.backgroundColor = blueColor
    }
Ryan Maneo
Ryan Maneo
4,342 Points
Ryan Maneo
Ryan Maneo
4,342 Points

I forgot view... dang... also how do I know where to put what? In this case, to put blueColor in the viewDidLoad method.

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

Actually, there was a third problem. You can't have () after **backgroundColor*8, as it's not a method.

As to where to put things, my code was wrong (but accepted by the editor!!). The challenge asked for a stored property to the view controller (i.e., the ViewController class). So here's what I should have done:

class ViewController: UIViewController {
    let blueColor = UIColor(red: 0, green: 0, blue: 255, alpha: 1.0)  //Task 1 stored property

    override func viewDidLoad() {
        // Do any additional setup after loading the view, typically from a nib.
        view.backgroundColor = blueColor  //assign color to view's background //Task 2
    }

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

Re where to put things: stored properties go in the class (and usual practice is to put them first, above methods).

But the view.backgroundColor = . . . code can't go there because, in part, there's not yet a view object to assign a color to. So this code has to be in the viewDidLoad() method, i.e., in a method that doesn't run until after the view has loaded (and therefore exists and can be changed).