Uiview Duplicate

Duplicate, clone or copy UIView

Sure. The documentation has a good example of how to achieve that; it's for UITableViewCell, but is a good approach to use here as well.

Depending on the complexity of your view, you might want to make it a custom view class, and give it its own IBOutlet properties for whatever subviews it has; in that case, you'd set the “Class Identity” of the view in Interface Builder to that class. Then your view controller could access those views on any given XIB-loaded view via, for instance, myLoadedView.someLabel, rather than having to use, e.g., [myLoadedView viewWithTag:3] as suggested by the aforelinked documentation.

Create a copy of a UIView in Swift

You can't arbitrarily copy an object. Only objects that implement the NSCopying protocol can be copied.

However, there is a workaround: Since UIViews can be serialized to disk (e.g. to load from a XIB), you could use NSKeyedArchiver and NSKeyedUnarchiver to create a serialized NSData describing your view, then de-serialize that again to get an independent but identical object.

UIView duplicate

The easiest (but probably not the fastest) way is to archive it into an NSData object and unarchive it right away.

NSData *tempArchive = [NSKeyedArchiver archivedDataWithRootObject:myView];
UIView *myViewDuplicate = [NSKeyedUnarchiver unarchiveObjectWithData:tempArchive];

How to make copy UIView and save accessibilityId programmatically?

This appears to be an Apple bug. You should really report this on Apple Bug Reporter.

That said, you can work around the issue as follows:

extension UIView {
    func copyView<T: UIView>() -> T {
        let copy = NSKeyedUnarchiver.unarchiveObject(with: NSKeyedArchiver.archivedData(withRootObject: self)) as! T
        copy.accessibilityIdentifier = accessibilityIdentifier
        return copy
    }
}

Can UIView be copied?

Your app probably crashes with something like:

 [UIView copyWithZone:]: unrecognized selector sent to instance 0x1c6280

The reason is that UIView does not implement the copying protocol, and therefore there is no copyWithZone selector in UIView.

How to duplicate an UIView designed in a storyboard?

Cheap way, give the view a tag.

then UIView *view = [UIView viewWithTag:tag];

and then go ahead and copy it, add it to the view.

Or try this:

id copyOfView = [NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:originalView]];

Bear in mind that not everything necessarily gets archived and unarchived correctly (custom fonts, layer settings like corner radius) and IBOutlets should be steered clear of as they don't get updated on the cloned objects.

Are UIViews duplicated when adding a subview again in Swift?

I guess we are talking about UIViews and not Layers here?!

In this case usernameLabel is just added once even if you call addSubview multiple times.

To avoid any ambiguity here some code:

let baseView = UIView()
let dateLabel = UILabel()
let usernameLabel = UILabel()

override func viewDidLoad() {
    super.viewDidLoad()

    baseView.tag = 1
    usernameLabel.tag = 2
    dateLabel.tag = 3

    self.view.addSubview(self.baseView)

    self.baseView.addSubview(self.usernameLabel)
    self.baseView.addSubview(self.dateLabel)
    self.baseView.addSubview(self.usernameLabel)

    self.traverseViewHierarchy(view: self.baseView, level: 0)

}

private func traverseViewHierarchy(view: UIView, level: Int) {
    for _ in 0...level {
        print (" | ", terminator: "")
    }
    print ("view: \(view.tag)")
    for view in view.subviews {
        self.traverseViewHierarchy(view: view, level: level + 1)
    }
}

This add some tags to the mention views and gives it out in the console:

| view: 1
|  | view: 3
|  | view: 2

As you can see usernameLabel is just added once to the view hierarchy.

CollectionView duplicate inside UIView

the simplest way to fix this will be to replace

print(genrView)

with:

collectionView.reloadData()

in your

var genrView : [String] = []{
    didSet {
        collectionView.reloadData()
    }
}