accessing UIView subclass in view controller - ios

Question

Let's say I have SomeViewController: UIViewController, and I have a custom view CustomView: UIView, defined as a XIB, that I want to display. This custom view will be reused in other view controllers and even multiple times in the same view controller.
class CustomView: UIView {
#IBOutlet public var label: UILabel!
}
The way I have always added this view has been:
class UIExamples: UIViewController {
#IBOutlet private var myView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Assume makeViewFromNib returns the view [0] in the Nib.
let customView = makeViewFromNib(nib: "\(CustomView.self)", owner: self) as! CustomView
customView.frame = myView.bounds
myView.addSubview(customView)
}
}
Let's say that later on I want to modify something about the CustomView via a public property label.
I could do it inside viewDidLoad ONLY BECAUSE I have access to customView, but what if I want to change it in some other function? What I have seen is that one would have to do
let customView = myView.subviews[0] as! CustomView
customView.label.text = "some text"
which does not look right.
So, I thought the right way should be this:
class UIExamples: UIViewController {
#IBOutlet public var customView: CustomView! // Now this is always a CustomView type
override func viewDidLoad() {
super.viewDidLoad()
// Assume makeViewFromNib returns the view [0] in the Nib.
customView = makeViewFromNib(nib: "\(CustomView.self)", owner: self) as! CustomView
customView.label.text = "some text" // DOES NOT WORK!
}
}
That last line customView.label.text does not work. In fact, the label is not even seen on the screen. What am I doing wrong?

Answer 1

OK, didn't read (or maybe was reading before edit) that you use xib. If ViewController is created from xib with label in it this will be correct way:
set myView class in xib here:
and then connect IBOutlet (remove current one from xib here:
and then from code).
Now myView.label.text = "some text" should work without further issues.
Good luck!
If you create your view from code do it in this manner:
class UIExamples: UIViewController {
#IBOutlet private var myView: CustomView!
override func viewDidLoad() {
super.viewDidLoad()
// Assume makeViewFromNib returns the view [0] in the Nib.
myView = makeViewFromNib(nib: "\(CustomView.self)", owner: self) as! CustomView
myView.frame = view.bounds
view.addSubview(myView)
}
}
Because you already have property storing this view in your view controller it's unnecessary to dig inside subviews, it will work like that
myView.label.text = "some text"
And reason for
customView = makeViewFromNib(nib: "\(CustomView.self)", owner: self) as! CustomView
customView.label.text = "some text"
isn't working is because it's completely new view that wasn't added to your view controller subviews (also frame wasn't set BTW). And because you changed value of your customView property it's now not pointing to old instance of view, that is present in subviews (you can still see that "old one" but not change it).
But I really recommend to use pointer created once, as correct class to avoid casting. (Or creating view directly in xib / storyboard, otherwise #IBOutlet is not necessary)

Answer 2

Posting my own answer.
Create the XIB file.
Create the UIView subclass Swift file.
Under the XIB file owner's Identify Inspector custom class field, type in the UIView subclass name (your custom view).
Under the XIB file owner's Connections Inspector, make sure all IBOutlets in the Swift file are connected.
Add a view to the view controller and under its Identify Inspector custom class type, specify the custom class name.
Important:
* In your XIB swift file, you have to properly load the XIB content view.
...
/// Initializer used by Interface Builder.
required init?(coder: NSCoder) {
super.init(coder: coder)
configure()
}
/// Initializer used programmatically.
override init(frame: CGRect) {
super.init(frame: frame)
configure()
}
...
func configure() {
let contentView = // here use many of the functions available on the internet to
// load a view from a nib.
// Then add this view to the view hierarchy.
addSubview(contentView)
}