185

Here is my Objective-C code which I'm using to load a nib for my customised UIView:

-(id)init{

    NSArray *subviewArray = [[NSBundle mainBundle] loadNibNamed:@"myXib" owner:self options:nil];
    return [subviewArray objectAtIndex:0];

}

What is the equivalent code in Swift?

30 Answers 30

405

My contribution:

extension UIView {
    class func fromNib<T: UIView>() -> T {
        return Bundle(for: T.self).loadNibNamed(String(describing: T.self), owner: nil, options: nil)![0] as! T
    }
}

Then call it like this:

let myCustomView: CustomView = UIView.fromNib()

..or even:

let myCustomView: CustomView = .fromNib()
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23 Comments

Best answer by far.
Best answer here. Clean and Simple
@YuchenZhong - I prefer [0] over .first as that would return an optional. If you force unwrap it, it wouldn't be safer. ...and this begs the question: Why not return an optional as some of the above solutions? Answer: You can. Nothing wrong with that. But... if it would ever return nil, the name of the xib/class do not match. This is a developer mistake and should be caught immediately and never make it to production. Here I would prefer to have the app crash over leaving it in some weird state. Just my 2 cents / preference.
@allenlinli - The method is a static extension of UIView as supposed to CustomView. It works because the compiler infers type using the explicit type annotation. Because CustomView is a subclass of UIView and the type has already been inferred, we don’t need to infer it again, UIView can therefore be omitted as shown in my second example. Having that said, you could obviously make the call the way you put it down too.
This solution didn't work for me for the case when there was a custom view inside the .xib. I would suggest to fix this part to: return Bundle.main.loadNibNamed(String(describing: self), owner: nil, options: nil)![0] as! T
|
192

Original Solution

  1. I created a XIB and a class named SomeView (used the same name for convenience and readability). I based both on a UIView.
  2. In the XIB, I changed the "File's Owner" class to SomeView (in the identity inspector).
  3. I created a UIView outlet in SomeView.swift, linking it to the top level view in the XIB file (named it "view" for convenience). I then added other outlets to other controls in the XIB file as needed.
  4. in SomeView.swift, I loaded the XIB inside the "init with code" initializer. There is no need to assign anything to "self". As soon as the XIB is loaded, all outlets are connected, including the top level view. The only thing missing, is to add the top view to the view hierarchy:

.

class SomeView: UIView {
   required init(coder aDecoder: NSCoder) {
      super.init(coder: aDecoder)
      NSBundle.mainBundle().loadNibNamed("SomeView", owner: self, options: nil)
      self.addSubview(self.view);    // adding the top level view to the view hierarchy
   }
   ...
}

Note that this way I get a class that loads itself from nib. I could then use SomeView as a class whenever UIView could be used in the project (in interface builder or programmatically).

Update - using Swift 3 syntax

Loading a xib in the following extension is written as an instance method, which can then be used by an initializer like the one above:

extension UIView {

    @discardableResult   // 1
    func fromNib<T : UIView>() -> T? {   // 2
        guard let contentView = Bundle(for: type(of: self)).loadNibNamed(String(describing: type(of: self)), owner: self, options: nil)?.first as? T else {    // 3
            // xib not loaded, or its top view is of the wrong type
            return nil
        }
        self.addSubview(contentView)     // 4
        contentView.translatesAutoresizingMaskIntoConstraints = false   // 5 
        contentView.layoutAttachAll(to: self)   // 6 
        return contentView   // 7
    }
}
  1. Using a discardable return value since the returned view is mostly of no interest to caller when all outlets are already connected.
  2. This is a generic method that returns an optional object of type UIView. If it fails to load the view, it returns nil.
  3. Attempting to load a XIB file with the same name as the current class instance. If that fails, nil is returned.
  4. Adding the top level view to the view hierarchy.
  5. This line assumes we're using constraints to layout the view.
  6. This method adds top, bottom, leading & trailing constraints - attaching the view to "self" on all sides (See: https://stackoverflow.com/a/46279424/2274829 for details)
  7. Returning the top level view

And the caller method might look like this:

final class SomeView: UIView {   // 1.
   required init?(coder aDecoder: NSCoder) {   // 2 - storyboard initializer
      super.init(coder: aDecoder)
      fromNib()   // 5.
   }
   init() {   // 3 - programmatic initializer
      super.init(frame: CGRect.zero)  // 4.
      fromNib()  // 6.
   }
   // other methods ...
}
  1. SomeClass is a UIView subclass that loads its content from a SomeClass.xib file. The "final" keyword is optional.
  2. An initializer for when the view is used in a storyboard (remember to use SomeClass as the custom class of your storyboard view).
  3. An initializer for when the view is created programmatically (i.e.: "let myView = SomeView()").
  4. Using an all-zeros frame since this view is laid out using auto-layout. Note that an "init(frame: CGRect) {..}" method is not created independently, since auto-layout is used exclusively in our project.
  5. & 6. Loading the xib file using the extension.

Credit: Using a generic extension in this solution was inspired by Robert's answer below.

Edit Changing "view" to "contentView" to avoid confusion. Also changed the array subscript to ".first".

21 Comments

Setting the class name to File's Owner hit the spot... Thanks!
UIView doesn't have property view, so calling self.view causes an error
@NastyaGorban self.view actually refers in this case to the outlet property (named "view) that GK100 linked from the top level view in the .xib to SomeView.swift. Not adding that outlet will give you error as there is no "view" property in NSView classes as you say.
I am getting crash when loading nib(loadNibNamed). Using Xcode 6.3 and Swift
calling fromNib() from within init(coder aDecoder: NSCoder) creates an infinite loop as loading the Nib inside the fromNib() method makes a call to: init(coder aDecoder: NSCoder)
|
94

Now being able to return -> Self in swift helps simplify this a bit. Last confirmed on Swift 5.

extension UIView {
    class func fromNib(named: String? = nil) -> Self {
        let name = named ?? "\(Self.self)"
        guard
            let nib = Bundle.main.loadNibNamed(name, owner: nil, options: nil)
            else { fatalError("missing expected nib named: \(name)") }
        guard
            /// we're using `first` here because compact map chokes compiler on
            /// optimized release, so you can't use two views in one nib if you wanted to
            /// and are now looking at this
            let view = nib.first as? Self
            else { fatalError("view of type \(Self.self) not found in \(nib)") }
        return view
    }
}

If your .xib file and subclass share the same name, you can use:

let view = CustomView.fromNib()

If you have a custom name, use:

let view = CustomView.fromNib(named: "special-case")

NOTE:

If you're getting the error "view of type YourType not found in.." then you haven't set the view's class in the .xib file

Select your view in the .xib file, and press cmd + opt + 4 and in the class input, enter your class

10 Comments

I cannot get this to work under XCode 7.1 beta 3 - not sure if it's a beta thing but basically I've tried every way to create a custom view directly from a nib in Swift and I always get the same result: the class it's creating is not KVC compliant with the outlets. Not sure if it's something I'm doing wrong but my class is pretty simple and the File's Owner is correct. I used to do this all the time under Objective-C.
@Logan it's not really related to your code, but imo custom views should support loading from Storyboard/XIB. My comment was just a notification for those, who want to create such views
Note I still have a problem using the second form of calling this function, namely let myCustomView = UIView.fromNib() as? CustomView. In this case, T.self resolves to UIView rather than CustomView and it fails to find the nib. I am not sure why this is - maybe the inferred type for the let means the function is called as a UIView?
It is important to point out that trying to use File's Owner to hook up the outlets (as we did in the good olde days) will cause this to crash. In IB, the File's Owner must be nil/empty and the outlets should be hooked up to the view instead.
@Echelon you saved my day!!! I connected my outlets using the File's Owner and it didn't work, using the view instead worked.
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27

Swift 4 - 5.1 Protocol Extensions

public protocol NibInstantiatable {
    
    static func nibName() -> String
    
}

extension NibInstantiatable {
    
    static func nibName() -> String {
        return String(describing: self)
    }
    
}

extension NibInstantiatable where Self: UIView {
    
    static func fromNib() -> Self {
        
        let bundle = Bundle(for: self)
        let nib = bundle.loadNibNamed(nibName(), owner: self, options: nil)
        
        return nib!.first as! Self
        
    }
    
}

Adoption

class MyView: UIView, NibInstantiatable {

}

This implementation assumes that the Nib has the same name as the UIView class. Ex. MyView.xib. You can modify this behavior by implementing nibName() in MyView to return a different name than the default protocol extension implementation.

In the xib the files owner is MyView and the root view class is MyView.

Usage

let view = MyView.fromNib()

2 Comments

This is by far the most elegant, straightforward solution and I have no idea why it's not the accepted answer!
@horseshoe7 because its written 4 years after the question.
22

try following code.

var uiview :UIView?

self.uiview = NSBundle.mainBundle().loadNibNamed("myXib", owner: self, options: nil)[0] as? UIView

Edit:

import UIKit

class TestObject: NSObject {

     var uiview:UIView?

    init()  {
        super.init()
       self.uiview = NSBundle.mainBundle().loadNibNamed("myXib", owner: self, options: nil)[0] as? UIView
    }


}

1 Comment

I need to call this method inside the object initialisation method which is init() in Swift.
15

If you have a lot of custom views in your project you can create class like UIViewFromNib

Swift 2.3

class UIViewFromNib: UIView {
    
    var contentView: UIView!
    
    var nibName: String {
        return String(self.dynamicType)
    }
    
    //MARK:
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        loadViewFromNib()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        
        loadViewFromNib()
    }
    
    //MARK:
    private func loadViewFromNib() {
        contentView = NSBundle.mainBundle().loadNibNamed(nibName, owner: self, options: nil)[0] as! UIView
        contentView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
        contentView.frame = bounds
        addSubview(contentView)
    }
}

Swift 5

class UIViewFromNib: UIView {
    
    var contentView: UIView!
    
    var nibName: String {
        return String(describing: type(of: self))
    }
    
    //MARK:
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        loadViewFromNib()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        
        loadViewFromNib()
    }
    
    //MARK:
    func loadViewFromNib() {
        let bundle = Bundle(for: UIViewFromNib.self)
        contentView = UINib(nibName: nibName, bundle: bundle).instantiate(withOwner: self).first as? UIView
        contentView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        contentView.frame = bounds
        addSubview(contentView)
    }
}

And in every class just inherit from UIViewFromNib, also you can override nibName property if .xib file has different name:

class MyCustomClass: UIViewFromNib {
    
}

Comments

12

I achieved this with Swift by the following code:

class Dialog: UIView {
    @IBOutlet var view:UIView!

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.frame = UIScreen.mainScreen().bounds
        NSBundle.mainBundle().loadNibNamed("Dialog", owner: self, options: nil)
        self.view.frame = UIScreen.mainScreen().bounds
        self.addSubview(self.view)
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

Don't forget to connect your XIB view outlet to view outlet defined in swift. You can also set First Responder to your custom class name to start connecting any additional outlets.

Hope this helps!

Comments

11

Tested in Xcode 7 beta 4 , Swift 2.0 and iOS9 SDK . The following code will assign xib to the uiview. You can able to use this custom xib view in storyboard and access the IBOutlet object also.

import UIKit

@IBDesignable class SimpleCustomView:UIView
{
    var view:UIView!;

    @IBOutlet weak var lblTitle: UILabel!

   @IBInspectable var lblTitleText : String?
        {
        get{
            return lblTitle.text;
        }
        set(lblTitleText)
        {
            lblTitle.text = lblTitleText!;
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        loadViewFromNib ()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        loadViewFromNib ()
    }
    func loadViewFromNib() {
        let bundle = NSBundle(forClass: self.dynamicType)
        let nib = UINib(nibName: "SimpleCustomView", bundle: bundle)
        let view = nib.instantiateWithOwner(self, options: nil)[0] as! UIView
        view.frame = bounds
        view.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
        self.addSubview(view);



    }


}

Access customview programatically

self.customView =  SimpleCustomView(frame: CGRectMake(100, 100, 200, 200))
        self.view.addSubview(self.customView!);

Source code - https://github.com/karthikprabhuA/CustomXIBSwift

Comments

9

Building on the above solutions.

This will work across all project bundles and no need for generics when calling fromNib().

Swift 2

extension UIView {

    public class func fromNib() -> Self {
        return fromNib(nil)
    }

    public class func fromNib(nibName: String?) -> Self {

        func fromNibHelper<T where T : UIView>(nibName: String?) -> T {
            let bundle = NSBundle(forClass: T.self)
            let name = nibName ?? String(T.self)
            return bundle.loadNibNamed(name, owner: nil, options: nil)?.first as? T ?? T()
        }
        return fromNibHelper(nibName)
    }
}

Swift 3

extension UIView {

    public class func fromNib() -> Self {
        return fromNib(nibName: nil)
    }

    public class func fromNib(nibName: String?) -> Self {
        func fromNibHelper<T>(nibName: String?) -> T where T : UIView {
            let bundle = Bundle(for: T.self)
            let name = nibName ?? String(describing: T.self)
            return bundle.loadNibNamed(name, owner: nil, options: nil)?.first as? T ?? T()
        }
        return fromNibHelper(nibName: nibName)
    }
}

Can be used like this:

let someView = SomeView.fromNib()

Or like this:

let someView = SomeView.fromNib("SomeOtherNibFileName")

Comments

9

Swift 4

Don't forget to write ".first as? CustomView".

if let customView = Bundle.main.loadNibNamed("myXib", owner: self, options: nil)?.first as? CustomView {    
    self.view.addSubview(customView)
    }

If you want to use anywhere

The Best Solution is Robert Gummesson's answer.

extension UIView {
    class func fromNib<T: UIView>() -> T {
        return Bundle.main.loadNibNamed(String(describing: T.self), owner: nil, options: nil)![0] as! T
    }
}

Then call it like this:

let myCustomView: CustomView = UIView.fromNib()

Comments

8

Updated for Swift 5

Somewhere define below:

extension UIView {
    public class func fromNib<T: UIView>() -> T {
        let name = String(describing: Self.self);
        guard let nib = Bundle(for: Self.self).loadNibNamed(
                name, owner: nil, options: nil)
        else {
            fatalError("Missing nib-file named: \(name)")
        }
        return nib.first as! T
    }
}

And use above like:

let view: MyCustomView = .fromNib();

Which will search in same bundle as MyCustomView, then load MyCustomView.nib file (if file exists, and is added to project).

Comments

7

I prefer this solution (based on the answer if @GK100):

  1. I created a XIB and a class named SomeView (used the same name for convenience and readability). I based both on a UIView.
  2. In the XIB, I changed the "File's Owner" class to SomeView (in the identity inspector).
  3. I created a UIView outlet in SomeView.swift, linking it to the top level view in the XIB file (named it "view" for convenience). I then added other outlets to other controls in the XIB file as needed.
  4. In SomeView.swift, I loaded the XIB inside the init or init:frame: CGRect initializer. There is no need to assign anything to "self". As soon as the XIB is loaded, all outlets are connected, including the top level view. The only thing missing, is to add the top view to the view hierarchy:

    class SomeView: UIView {
      override init(frame: CGRect) {
        super.init(frame: frame)
        NSBundle.mainBundle().loadNibNamed("SomeObject", owner: self, options: nil)
        self.addSubview(self.view);    // adding the top level view to the view hierarchy
      }
    
      required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        NSBundle.mainBundle().loadNibNamed("SomeObject", owner: self, options: nil)
        self.addSubview(self.view);    // adding the top level view to the view hierarchy
      }
    
    
      ...
    }
    

1 Comment

i prefer to use init with frame so i uprooted this! one thing to note... add self.view.frame = frame if you'd like the view to match the frame you pass in
6

A nice way to do this with Swift is to use an enum.

enum Views: String {
    case view1 = "View1" // Change View1 to be the name of your nib
    case view2 = "View2" // Change View2 to be the name of another nib

    func getView() -> UIView? {
        return NSBundle.mainBundle().loadNibNamed(self.rawValue, owner: nil, options: nil).first as? UIView
    }
}

Then in your code you can simply use:

let view = Views.view1.getView()

1 Comment

Note that if you do this with an empty nib file or a nib file with a none UIView root node you will crash as you are not sanity checking array size or the element in position 0.
5
let subviewArray = NSBundle.mainBundle().loadNibNamed("myXib", owner: self, options: nil)
return subviewArray[0]

3 Comments

But in init() of Swift, there is no returned value. I forgot to mention I need to call loadNibNamed in the initialization of an UIView.
What do you mean "no return value"? self is implicitly returned from all init methods...
What I mean is I call loadNibNamed inside the init method. the loaded UIView is assigned to self in ObjC. But in swift, it's not.
5

Swift 5 - Clean and easy to use extension

[Copy Paste from production project]

//
//  Refactored by Essam Mohamed Fahmi.
//

import UIKit

extension UIView
{
   static var nib: UINib
   {
      return UINib(nibName: "\(self)", bundle: nil)
   }

   static func instantiateFromNib() -> Self?
   {
      return nib.instantiate() as? Self
   }
}

extension UINib
{
   func instantiate() -> Any?
   {
      return instantiate(withOwner: nil, options: nil).first
   }
}

Usage

let myCustomView: CustomView = .instantiateFromNib()

Comments

5

I just do this way :

if let myView = UINib.init(nibName: "MyView", bundle: nil).instantiate(withOwner: self)[0] as? MyView {
    // Do something with myView
}

This sample uses the first view in the nib "MyView.xib" in the main bundle. But you can vary either the index, the nib name, or the bundle ( main by default ).

I used to awake views into the view init method or make generic methods as in the proposed answers above ( which are smart by the way ), but I don't do it anymore because I have noticed use cases are often different, and to cover all cases, generic methods become as complex as using the UINib.instantiate method.

I prefer to use a factory object, usually the ViewController that will use the view, or a dedicated factory object or view extension if the view needs to be used in multiple places.

In this example, a ViewController loads a view from nib. The nib file can be changed to use different layouts for the same view class. ( This not nice code, it just illustrates the idea )

class MyViewController {
    // Use "MyView-Compact" for compact version
    var myViewNibFileName = "MyView-Standard"

    lazy var myView: MyView = {
        // Be sure the Nib is correct, or it will crash
        // We don't want to continue with a wrong view anyway, so ! is ok
        UINib.init(nibName: myViewNibFileName, bundle: nil).instantiate(withOwner: self)[0] as! MyView
    }()
}

Comments

4

Swift 3 version of Logan's answer

extension UIView {
    public class func fromNib(nibName: String? = nil) -> Self {
        return fromNib(nibName: nibName, type: self)
    }

    public class func fromNib<T: UIView>(nibName: String? = nil, type: T.Type) -> T {
        return fromNib(nibName: nibName, type: T.self)!
    }

    public class func fromNib<T: UIView>(nibName: String? = nil, type: T.Type) -> T? {
        var view: T?
        let name: String

        if let nibName = nibName {
            name = nibName
        } else {
            name = self.nibName
        }

        if let nibViews = Bundle.main.loadNibNamed(name, owner: nil, options: nil) {
            for nibView in nibViews {
                if let tog = nibView as? T {
                    view = tog
                }
            }
        }

        return view
    }

    public class var nibName: String {
        return "\(self)".components(separatedBy: ".").first ?? ""
    }

    public class var nib: UINib? {
        if let _ = Bundle.main.path(forResource: nibName, ofType: "nib") {
            return UINib(nibName: nibName, bundle: nil)
        } else {
            return nil
        }
    }
}

Comments

4

Here is a clean and declarative way of programmatically loading a view using a protocol and protocol extension (Swift 4.2):

protocol XibLoadable {
    associatedtype CustomViewType
    static func loadFromXib() -> CustomViewType
}

extension XibLoadable where Self: UIView {
    static func loadFromXib() -> Self {
        let nib = UINib(nibName: "\(self)", bundle: Bundle(for: self))
        guard let customView = nib.instantiate(withOwner: self, options: nil).first as? Self else {
            // your app should crash if the xib doesn't exist
            preconditionFailure("Couldn't load xib for view: \(self)")
        }
        return customView
    }
}

And you can use this like so:

// don't forget you need a xib file too
final class MyView: UIView, XibLoadable { ... }

// and when you want to use it
let viewInstance = MyView.loadFromXib()

Some additional considerations:

  1. Make sure your custom view's xib file has the view's Custom Class set (and outlets/actions set from there), not the File Owner's.
  2. You can use this protocol/extension external to your custom view or internal. You may want to use it internally if you have some other setup work when initializing your view.
  3. Your custom view class and xib file need to have the same name.

Comments

2

All you have to do is call init method in your UIView class.

Do it that way:

class className: UIView {

    @IBOutlet var view: UIView!

    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)!
    }

    func setup() {
        UINib(nibName: "nib", bundle: nil).instantiateWithOwner(self, options: nil)
        addSubview(view)
        view.frame = self.bounds
    }
}

Now, if you want to add this view as a sub view in view controller, do it that way in view controller.swift file:

self.view.addSubview(className())

2 Comments

it's great answer but there is something wrong, i will edit it.
It is the way i implemented. But you can improvise it. Thanks in advance @C0mrade
1

Similar to some of the answers above but a more consistent Swift3 UIView extension:

extension UIView {
    class func fromNib<A: UIView> (nibName name: String, bundle: Bundle? = nil) -> A? {
        let bundle = bundle ?? Bundle.main
        let nibViews = bundle.loadNibNamed(name, owner: self, options: nil)
        return nibViews?.first as? A
    }

    class func fromNib<T: UIView>() -> T? {
        return fromNib(nibName: String(describing: T.self), bundle: nil)
    }
}

Which gives the convenience of being able to load the class from a self named nib but also from other nibs/bundles.

Comments

1

You can do this via storyboard, just add proper constraints for view. You can do this easily by subclassing any view from your own let's say BaseView:

Objective-C

BaseView.h


/*!
 @class BaseView
 @discussion Base View for getting view from xibFile
 @availability ios7 and later
 */
@interface BaseView : UIView

@end


BaseView.m


#import "BaseView.h"

@implementation BaseView

#pragma mark - Public

- (instancetype)initWithCoder:(NSCoder *)coder
{
    self = [super initWithCoder:coder];
    if (self) {
        [self prepareView];
    }
    return self;
}

#pragma mark - LifeCycle

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self prepareView];
    }
    return self;
}

#pragma mark - Private

- (void)prepareView
{
    NSArray *nibsArray = [[NSBundle mainBundle] loadNibNamed:NSStringFromClass([self class]) owner:self options:nil];
    UIView *view = [nibsArray firstObject];

    view.translatesAutoresizingMaskIntoConstraints = NO;
    [self addSubview:view];
    [self addConstraintsForView:view];
}

#pragma mark - Add constraints

- (void)addConstraintsForView:(UIView *)view
{
    [self addConstraints:@[[NSLayoutConstraint constraintWithItem:view
                                                        attribute:NSLayoutAttributeBottom
                                                        relatedBy:NSLayoutRelationEqual
                                                           toItem:self attribute:NSLayoutAttributeBottom
                                                       multiplier:1.0
                                                         constant:0],
                           [NSLayoutConstraint constraintWithItem:view
                                                        attribute:NSLayoutAttributeTop
                                                        relatedBy:NSLayoutRelationEqual
                                                           toItem:self attribute:NSLayoutAttributeTop
                                                       multiplier:1.0
                                                         constant:0],
                           [NSLayoutConstraint constraintWithItem:view
                                                        attribute:NSLayoutAttributeLeft
                                                        relatedBy:NSLayoutRelationEqual
                                                           toItem:self attribute:NSLayoutAttributeLeft
                                                       multiplier:1.0
                                                         constant:0],
                           [NSLayoutConstraint constraintWithItem:view
                                                        attribute:NSLayoutAttributeRight
                                                        relatedBy:NSLayoutRelationEqual
                                                           toItem:self attribute:NSLayoutAttributeRight
                                                       multiplier:1.0
                                                         constant:0]
                           ]];
}

@end

Swift 4

import UIKit

class BaseView : UIView {

    // MARK: - LifeCycle

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        prepareView()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        prepareView()
    }

    internal class func xibName() -> String {
        return String(describing: self)
    }

    // MARK: - Private
    fileprivate func prepareView() {
        let nameForXib = BaseView.xibName()
        let nibs = Bundle.main.loadNibNamed(nameForXib, owner: self, options: nil)
        if let view = nibs?.first as? UIView {
            view.backgroundColor = UIColor.clear
            view.translatesAutoresizingMaskIntoConstraints = false
            addSubviewWithConstraints(view, offset: false)
        }
    }
}

UIView+Subview


public extension UIView {
    // MARK: - UIView+Extensions

    public func addSubviewWithConstraints(_ subview:UIView, offset:Bool = true) {
        subview.translatesAutoresizingMaskIntoConstraints = false
        let views = [
            "subview" : subview
        ]
        addSubview(subview)

        var constraints = NSLayoutConstraint.constraints(withVisualFormat: offset ? "H:|-[subview]-|" : "H:|[subview]|", options: [.alignAllLeading, .alignAllTrailing], metrics: nil, views: views)
        constraints.append(contentsOf: NSLayoutConstraint.constraints(withVisualFormat: offset ? "V:|-[subview]-|" : "V:|[subview]|", options: [.alignAllTop, .alignAllBottom], metrics: nil, views: views))
        NSLayoutConstraint.activate(constraints)
    }
}

I provide 2 variants how to add constraints - common one and within visual format language - select any you want :)

Also, by default assumed that xib name has same name as implementation class name. If no - just change xibName parameter.

If you subclass your view from BaseView - you can easily put any view and specify class in IB.

Comments

1

If you want the Swift UIView subclass to be entirely self contained, and have the ability to be instantiated using init or init(frame:) without exposing the implementation detail of using a Nib, then you can use a protocol extension to achieve this. This solution avoids the nested UIView hierarchy as suggested by many of the other solutions.

public class CustomView: UIView {

    @IBOutlet weak var nameLabel: UILabel!
    @IBOutlet weak var valueLabel: UILabel!

    public convenience init() {
        self.init(frame: CGRect.zero)
    }

    public override convenience init(frame: CGRect) {
        self.init(internal: nil)
        self.frame = frame
    }

    public required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }

    fileprivate func commonInit() {
    }
}

fileprivate protocol _CustomView {
}

extension CustomView: _CustomView {
}

fileprivate extension _CustomView {

    // Protocol extension initializer - has the ability to assign to self, unlike
    // class initializers. Note that the name of this initializer can be anything
    // you like, here we've called it init(internal:)

    init(internal: Int?) {
        self = Bundle.main.loadNibNamed("CustomView", owner:nil, options:nil)![0] as! Self;
    }
}

1 Comment

This is an ingenious trick; the only downside is that you still can't write a fully custom init that also sets up stored properties since init(coder:) will be called further down the chain, which will expect said properties to already be set or to set them itself before getting back to the protocol-based init.
1
class func loadFromNib<T: UIView>() -> T {
    let nibName = String(describing: self)
    return Bundle.main.loadNibNamed(nibName, owner: nil, options: nil)![0] as! T
}

Comments

1
    let nibs = Bundle.main.loadNibNamed("YourView", owner: nil, options: nil)
    let shareView = nibs![0] as! ShareView
    self.view.addSubview(shareView)

Comments

1

// Use this class as super view

import UIKit

class ViewWithXib: UIView {

func initUI() {}

private func xibSetup() {
    let view = loadViewFromNib()
    view.frame = bounds
    view.autoresizingMask = [UIViewAutoresizing.flexibleWidth, UIViewAutoresizing.flexibleHeight]
    addSubview(view)
    initUI()
}

private func loadViewFromNib() -> UIView {
    let thisName = String(describing: type(of: self))
    let view = Bundle(for: self.classForCoder).loadNibNamed(thisName, owner: self, options: nil)?.first as! UIView
    return view
}


override init(frame: CGRect) {
    super.init(frame: frame)
    xibSetup()
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    xibSetup()
}

}

// Usages:

class HeaderView: ViewWithXib {
}


let header = HeaderView() // No need to load the view from nib, It will work

Comments

1

Robert Gummesson's Answer is perfect. But when we try to use it in SPM or framework it is not working.
I've modified like below to make it work.

internal class func fromNib<T: UIView>() -> T {
    return Bundle.module.loadNibNamed(String(describing: T.self), owner: self, options: nil)![0] as! T
}

Comments

0

More powerful version based on Logan's answer

extension UIView {
    public class func fromNib(nibName: String? = nil) -> Self {
        return fromNib(nibName: nibName, type: self)
    }

    public class func fromNib<T: UIView>(nibName: String? = nil, type: T.Type) -> T {
        return fromNib(nibName: nibName, type: T.self)!
    }

    public class func fromNib<T: UIView>(nibName: String? = nil, type: T.Type) -> T? {
        var view: T?
        let name: String

        if let nibName = nibName {
            name = nibName
        } else {
            name = self.nibName
        }

        if let nibViews = nibBundle.loadNibNamed(name, owner: nil, options: nil) {
            if nibViews.indices.contains(nibIndex), let tog = nibViews[nibIndex] as? T {
                view = tog
            }
        }

        return view
    }

    public class var nibName: String {
        return "\(self)".components(separatedBy: ".").first ?? ""
    }

    public class var nibIndex: Int {
        return 0
    }

    public class var nibBundle: Bundle {
        return Bundle.main
    }
}

And you can use like

class BaseView: UIView {
    override class var nibName: String { return "BaseView" }
    weak var delegate: StandardStateViewDelegate?
}

class ChildView: BaseView {
    override class var nibIndex: Int { return 1 }
}

Comments

0

The most convenient implementation. Here you need two methods, in order to return directly to the object of your class, not UIView.

  1. viewId marked as a class, allowing override
  2. Your .xib can contain more than one view of the top level, this situation is also handled correctly.

extension UIView {

class var viewId: String {
    return String(describing: self)
}

static func instance(from bundle: Bundle? = nil, nibName: String? = nil,
                    owner: Any? = nil, options: [AnyHashable : Any]? = nil) -> Self? {

    return instancePrivate(from: bundle ?? Bundle.main,
                           nibName: nibName ?? viewId,
                           owner: owner,
                           options: options)
}

private static func instancePrivate<T: UIView>(from bundle: Bundle, nibName: String,
                                              owner: Any?, options: [AnyHashable : Any]?) -> T? {

    guard
        let views = bundle.loadNibNamed(nibName, owner: owner, options: options),
        let view = views.first(where: { $0 is T }) as? T else { return nil }

    return view
}
}

Example:

guard let customView = CustomView.instance() else { return }

//Here customView has CustomView class type, not UIView.
print(customView is CustomView) // true

Comments

0
  let bundle = Bundle(for: type(of: self))
   let views = bundle.loadNibNamed("template", owner: self, options: nil)
    self.view.addSubview(views?[0] as! UIView)

1 Comment

Code only answers are discouraged. Please add some explanation as to how this solves the problem, or how this differs from the existing answers. From Review
0

I prefer the below extension

extension UIView {
    class var instanceFromNib: Self {
        return Bundle(for: Self.self)
            .loadNibNamed(String(describing: Self.self), owner: nil, options: nil)?.first as! Self
    }
}

The difference between this and the top answered extension is you don't need to store it an constant or variable.

class TitleView: UIView { }

extension UIView {
    class var instanceFromNib: Self {
        return Bundle(for: Self.self)
            .loadNibNamed(String(describing: Self.self), owner: nil, options: nil)?.first as! Self
    }
}

self.navigationItem.titleView = TitleView.instanceFromNib

1 Comment

What version of Xcode are you using? Please make sure you are using the latest version of XCode. Works fine for me with XCode 11.5 (latest version as on date).

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