How to initialize/instantiate a custom UIView class with a XIB file in Swift
I have a class called MyClass
which is a subclass of UIView
, that I want to initialize with a XIB
file. I am not sure how to initialize this class with the xib file called View.xib
class MyClass: UIView {
// what should I do here?
//init(coder aDecoder: NSCoder) {} ??
}
I tested this code and it works great:
class MyClass: UIView {
class func instanceFromNib() -> UIView {
return UINib(nibName: "nib file name", bundle: nil).instantiateWithOwner(nil, options: nil)[0] as UIView
}
}
Initialise the view and use it like below:
var view = MyClass.instanceFromNib()
self.view.addSubview(view)
OR
var view = MyClass.instanceFromNib
self.view.addSubview(view())
UPDATE Swift >=3.x & Swift >=4.x
class func instanceFromNib() -> UIView {
return UINib(nibName: "nib file name", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! UIView
}
Sam's solution is already great, despite it doesn't take different bundles into account (NSBundle:forClass comes to the rescue) and requires manual loading, a.k.a typing code.
If you want full support for your Xib Outlets, different Bundles (use in frameworks!) and get a nice preview in Storyboard try this:
// NibLoadingView.swift
import UIKit
/* Usage:
- Subclass your UIView from NibLoadView to automatically load an Xib with the same name as your class
- Set the class name to File's Owner in the Xib file
*/
@IBDesignable
class NibLoadingView: UIView {
@IBOutlet weak var view: UIView!
override init(frame: CGRect) {
super.init(frame: frame)
nibSetup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
nibSetup()
}
private func nibSetup() {
backgroundColor = .clearColor()
view = loadViewFromNib()
view.frame = bounds
view.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
view.translatesAutoresizingMaskIntoConstraints = true
addSubview(view)
}
private func loadViewFromNib() -> UIView {
let bundle = NSBundle(forClass: self.dynamicType)
let nib = UINib(nibName: String(self.dynamicType), bundle: bundle)
let nibView = nib.instantiateWithOwner(self, options: nil).first as! UIView
return nibView
}
}
Use your xib as usual, i.e. connect Outlets to File Owner and set File Owner class to your own class.
Usage: Just subclass your own View class from NibLoadingView & Set the class name to File's Owner in the Xib file
No additional code required anymore.
Credits where credit's due: Forked this with minor changes from DenHeadless on GH. My Gist: https://gist.github.com/winkelsdorf/16c481f274134718946328b6e2c9a4d8
As of Swift 2.0, you can add a protocol extension. In my opinion, this is a better approach because the return type is Self
rather than UIView
, so the caller doesn't need to cast to the view class.
import UIKit
protocol UIViewLoading {}
extension UIView : UIViewLoading {}
extension UIViewLoading where Self : UIView {
// note that this method returns an instance of type `Self`, rather than UIView
static func loadFromNib() -> Self {
let nibName = "\(self)".characters.split{$0 == "."}.map(String.init).last!
let nib = UINib(nibName: nibName, bundle: nil)
return nib.instantiateWithOwner(self, options: nil).first as! Self
}
}