Can UIView be copied?

Question

Simply using this way:

UIView* view2 = [view1 copy]; // view1 existed

This will cause simulator can not launch this app.

Try retai

Answer 1

You can make an UIView extension. In example swift snippet below, function copyView returns an AnyObject so you could copy any subclass of an UIView, ie UIImageView. If you want to copy only UIViews you can change the return type to UIView.

//MARK: - UIView Extensions

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

Example usage:

let sourceView = UIView()
let copiedView = sourceView.copyView()

Answer 2

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.

Answer 3

You can make method something like this:

-(UILabel*)copyLabelFrom:(UILabel*)label{
//add whatever needs to be copied
UILabel *newLabel = [[UILabel alloc]initWithFrame:label.frame];
newLabel.backgroundColor = label.backgroundColor;
newLabel.textColor = label.textColor;
newLabel.textAlignment = label.textAlignment;
newLabel.text = label.text;
newLabel.font = label.font;

return [newLabel autorelease];

}

Then you can set your ivar to the return value and retain it like so:

myLabel = [[self copyLabelFrom:myOtherLabel] retain];

Answer 4

for swift3.0.1:

extension UIView{
 func copyView() -> AnyObject{
    return NSKeyedUnarchiver.unarchiveObject(with: NSKeyedArchiver.archivedData(withRootObject: self))! as AnyObject
 }
}

Answer 5

UIView doesn't implement the NSCoping protocol, see the declaration in UIView.h:

@interface UIView : UIResponder <NSCoding, UIAppearance, UIAppearanceContainer, UIDynamicItem, UITraitEnvironment, UICoordinateSpace, UIFocusEnvironment>

So, if we want to have a copy like method, we need to implement the NSCoping protocol in a category or so.

Answer 6

this might work for you ... archive the view and then unarchive it right after. This should give you a deep copy of a view:

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