Is this when I should be creating a class? - ios

Question

I'm trying to get to grip with Swift and wanted some advice...
I have a UIView that exists on a number of screens; specifically, it's a logo that uses a number of elements/parameters to style it correctly i.e. shadow, shape, image etc.
For my first viewcontroller I set this up as a function that is called from the viewDidLoad function. Then in my second viewcontroller I have the same logo... here is my question,
Should I load the first view controller from the story board and then reference the function in the second viewcontroller OR should I have just made the logo a class that either viewcontroller can reference? My gut says it should be a class...
Thanks in advance

Answer 1

For a reusable view you’d create a XIB in which you design the view plus a view controller class in which you instantiate the xib, like this:
class ReusableView: UIView {
override func awakeFromNib() {
super.awakeFromNib()
let bundle = Bundle(for: type(of: self))
let nib = UINib(nibName: "ReusableView", bundle: bundle)
if let view = nib.instantiate(withOwner: self, options: nil).first as? UIView {
view.frame = bounds
addSubview(view)
}
}
}
In your view controller(s), you’d then simply place a placeholder UIView at the desired location and set its custom type to ReusableView. By connecting an outlet from this view into your view controller you’d have access to the view’s properties.
Please note that you will have to leave the Custom View property in the XIB set as UIView and set File’s Owner to ReusableView instead. Otherwise you’ll create an infinite loop.

Answer 2

WARNING! As I pointed out on another answer, DO NOT load the same nib from within awakeFromNib, or else you'll create an infinite loop of loading nibs.
Your gut instinct is correct, I would say. Create a custom class for your reusable view to go in. If you decide to create a nib for your class, I recommend instantiating it from a static function.
class ReusableView: UIView {
static func newFromNib() -> ReusableView {
let bundle = Bundle(for: ReusableView.self)
let nib = UINib(nibName: "ReusableView", bundle: bundle)
guard let view = nib.instantiate(withOwner: self, options: nil).first as? ReusableView else {
preconditionFailure("Could not instantiate ReusableView")
}
return view
}
override func awakeFromNib() {
super.awakeFromNib()
// Configuration ONLY if you use a Nib.
}
override init(frame: CGRect) {
super.init(frame: frame)
// Configuration if you DO NOT use a nib
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
Then, you can use it in a view controller:
class ViewController: UIViewController {
#IBOutlet weak var reusableViewContainer: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Create a new instance of your reusable view
let reusableView = ReusableView.newFromNib()
// If not using a nib, just use the 'init(frame:)' method
// let reusableView = ReusableView(frame: .zero)
// Add your reusable view to the view hierarchy
self.reusableViewContainer.addSubview(reusableView)
// Layout your view as necessary:
// For example, if using AutoLayout:
self.reusableViewContainer.topAnchor.constraint(equalTo: reusableView.topAnchor).isActive = true
self.reusableViewContainer.bottomAnchor.constraint(equalTo: reusableView.bottomAnchor).isActive = true
self.reusableViewContainer.leadingAnchor.constraint(equalTo: reusableView.leadingAnchor).isActive = true
self.reusableViewContainer.trailingAnchor.constraint(equalTo: reusableView.trailingAnchor).isActive = true
}
}
Of course, you don't have to use a container view. Place it wherever you need it in your view hierarchy, and lay it out as you do for other views.