Loading xib information
Utilizing the contents of a xib file is a fairly rattling straightforward activity to do. You need to use the next two strategies to load the contents (aka. the view hierarchy) of the file.
let view = UINib(nibName: "CustomView", bundle: .most important).instantiate(withOwner: nil, choices: nil).first as! UIView
view.body = self.view.bounds
self.view.addSubview(view)
The snippet above will merely instantiate a view object from the xib file. You may have a number of root objects within the view hierarchy, however this time let’s simply choose the primary one and use that. I assume that in 99% of the instances that is what you may want to be able to get your customized views. Additionally you’ll be able to lengthen the UIView object with any of the options above to create a generic view loader. Extra on that later… 😊
This technique is fairly easy and low-cost, nonetheless there’s one little disadvantage. You may’t get named pointers (retailers) for the views, however just for the foundation object. In case you are placing design parts into your display, that is tremendous, but when you have to show dynamic information, you may need to attain out for the underlying views as nicely. 😃
Customized views with retailers & actions
So the correct option to load customized views from xib information goes one thing like this:
Inside your customized view object, you instantiate the xib file precisely the identical method as I instructed you proper up right here. 👆 The one distinction is that you just need not use the article array returned by the strategies, however you need to join your view objects by way of the interface builder, utilizing the File’s Proprietor as a reference level, plus a customized container view outlet, that’ll include all the things you want. 🤨
class CustomView: View {
@IBOutlet weak var containerView: UIView!
@IBOutlet weak var textLabel: UILabel!
override func initialize() {
tremendous.initialize()
let identify = String(describing: kind(of: self))
let nib = UINib(nibName: identify, bundle: .most important)
nib.instantiate(withOwner: self, choices: nil)
self.addSubview(self.containerView)
self.containerView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
self.containerView.topAnchor.constraint(equalTo: self.topAnchor),
self.containerView.bottomAnchor.constraint(equalTo: self.bottomAnchor),
self.containerView.leadingAnchor.constraint(equalTo: self.leadingAnchor),
self.containerView.trailingAnchor.constraint(equalTo: self.trailingAnchor),
])
}
}
So the initialize technique right here is simply loading the nib file with the proprietor of self. After the loading course of completed, your outlet pointers are going to be crammed with correct values from the xib file. There’s one very last thing that we have to do. Even the views from the xib file are “programmatically” linked to our customized view object, however visually they are not. So we have now so as to add our container view into the view hierarchy. 🤐
If you wish to use your customized view object, you simply should create a brand new occasion from it – inside a view controller – and at last be happy so as to add it as a subview!
One phrase about bounds, frames aka. springs and struts: f*ckng UGLY! That is two phrases. They’re thought of as a foul follow, so please use auto format, I’ve a pleasant tutorial about anchors, they’re wonderful and studying them takes about quarter-hour. 😅
class ViewController: UIViewController {
weak var customView: CustomView!
override func loadView() {
tremendous.loadView()
let customView = CustomView()
self.view.addSubview(customView)
NSLayoutConstraint.activate([
customView.topAnchor.constraint(equalTo: self.view.topAnchor),
customView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
customView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
customView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
])
self.customView = customView
}
override func viewDidLoad() {
tremendous.viewDidLoad()
self.customView.textLabel.textual content = "Lorem ipsum"
}
}
That is it, now you may have a totally working customized UIView object that masses a xib file to be able to use it is contents. Wasn’t so unhealthy, proper? 🤪
Another further factor. In case you do not wish to deal with views programmatically otherwise you merely do not need to fiddle with the loadView technique, simply take away it solely. Subsequent put the @IBOutlet key phrase proper earlier than your customized view class variable. Open your storyboard utilizing IB, then drag & drop a brand new UIView ingredient to your controller and join the customized view outlet. It ought to work like magic. 💫
I promised retailers and actions within the heading of this part, so let’s discuss a bit of bit about IBActions. They work precisely the identical as you’d anticipate them with controllers. You may merely hook-up a button to your customized view and delegate the motion to the customized view class. If you wish to ahead touches or particular actions to a controller, you need to use the delegate sample or go together with a easy block. 😎
Possession and container views
It’s potential to go away out all of the xib loading mechanism from the view occasion. We are able to create a set of extensions to be able to have a pleasant view loader with a customized view class from a xib file. This manner you do not want a container view anymore, additionally the proprietor of the file may be neglected from the sport, it is kind of the identical technique as reusable cells for tables and collections created by Apple. 🍎
You must know that going this manner you’ll be able to’t use your default UIView init strategies programmatically anymore, as a result of the xib file will care for the init course of. Additionally in case you are attempting to make use of this type of customized views from a storyboard or xib file, you will not have the ability to use your retailers, as a result of the correspondig xib of the view class will not be loaded. In any other case in case you are attempting to load it manyally you may run into an infinite loop and ultimately your app will crash like hell. 😈
import UIKit
extension UINib {
func instantiate() -> Any? {
return self.instantiate(withOwner: nil, choices: nil).first
}
}
extension UIView {
static var nib: UINib {
return UINib(nibName: String(describing: self), bundle: nil)
}
static func instantiate(autolayout: Bool = true) -> Self {
func instantiateUsingNib<T: UIView>(autolayout: Bool) -> T {
let view = self.nib.instantiate() as! T
view.translatesAutoresizingMaskIntoConstraints = !autolayout
return view
}
return instantiateUsingNib(autolayout: autolayout)
}
}
class CustomView: UIView {
@IBOutlet weak var textLabel: UILabel!
}
Identical to with desk or assortment view cells this time you need to set your customized view class on the view object, as a substitute of the File’s Proprietor. It’s a must to join your retailers and mainly you are finished with all the things. 🤞
Any longer you need to ALWAYS use the instantiate technique in your customized view object. The excellent news is that the operate is generic, returns the correct occasion kind and it is extremely reusable. Oh, btw. I already talked about the unhealthy information… 🤪
There’s additionally yet another method by overriding awakeAfter, however I’d not depend on that resolution anymore. In many of the instances you’ll be able to merely set the File’s Proprietor to your customized view, and go together with a container, that is a secure wager. In case you have particular wants you may want the second method, however please watch out with that. 😉
