iOS add / remove shadow from a view - ios

Question

I do not understand how to remove a shadow that was added to a view.
I add to my view in initWithFrame a shadow in this way:
self.layer.borderWidth = 2;
self.layer.borderColor = [UIColor clearColor].CGColor;
self.backgroundColor = [UIColor greenColor];
[self.layer setCornerRadius:8.0f];
CALayer *layer = self.layer;
layer.shadowOffset = CGSizeMake(2, 2);
layer.shadowColor = [[UIColor blackColor] CGColor];
layer.cornerRadius = 8.0f;
layer.shadowRadius = 3.0f;
layer.shadowOpacity = 0.80f;
layer.shadowPath = [[UIBezierPath bezierPathWithRect:layer.bounds] CGPath];
After in the execution of the app I want to remove the shadow from this view. I've tried using:
layer.hidden = YES;
or
self.layer.hidden = YES;
but this hides the view completely, not just the added shadow.
Is there a way to retrieve the added shadow from a view and then hide it?
Thanks!

Answer 1

I guess you could use the shadowOpacity property of your CALayer.
So this should work:
self.layer.shadowOpacity = 0;
See the CALayer's shadowOpacity documentation page
And to show your shadow use:
self.layer.shadowOpacity = 1.0;

Answer 2

Sorry, not sure the correct way, but have you tried changing the properties of the layer shadow? For example, one of these;
layer.shadowOffset = CGSizeMake(0, 0);
layer.shadowColor = [[UIColor clearColor] CGColor];
layer.cornerRadius = 0.0f;
layer.shadowRadius = 0.0f;
layer.shadowOpacity = 0.00f;

Answer 3

Swift 4.2
I am using this in my code for labels and navigation bar.
extension UIView {
func shadow(_ height: Int = 5) {
self.layer.masksToBounds = false
self.layer.shadowRadius = 4
self.layer.shadowOpacity = 1
self.layer.shadowColor = UIColor.gray.cgColor
self.layer.shadowOffset = CGSize(width: 0 , height: height)
}
func removeShadow() {
self.layer.shadowOffset = CGSize(width: 0 , height: 0)
self.layer.shadowColor = UIColor.clear.cgColor
self.layer.cornerRadius = 0.0
self.layer.shadowRadius = 0.0
self.layer.shadowOpacity = 0.0
}
}

Answer 4

I tried the other answers, the only thing that worked for me was to toggle layer.masksToBounds to true/false
lazy var myView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.backgroundColor = .white
view.layer.cornerRadius = 5
view.layer.shadowColor = UIColor.black.cgColor
view.layer.shadowOpacity = 3
view.layer.shadowOffset = .zero
view.layer.shadowRadius = 5
return view
}()
func showShadow() {
myView.layer.masksToBounds = false
}
func hideShadow() {
myView.layer.masksToBounds = true
}

Answer 5

the "layer" that you are trying to make hidden is the layer of the object that you are having a shadow to it's not a visible aspect.. only the objects with in the layer... it's rather confusing to conceptualize anyways, the only way to remove the shadow is to undo what you originally did, which was suggested above, there is no defined property that you can just toggle a bool and make the shadow go away

Answer 6

Swift 5.+
My solution was to add a shadowBackgroundView, which has a removable shadowLayer. In this way I could easyly remove the layer without resetting the shadow properties.
class ViewController: UIViewController {
private let shadowBackgroundView: UIView = {
let view = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
view.layer.masksToBounds = false
return view
}()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
view.addSubview(shadowBackgroundView)
// the view you want to add the shadow
let dummyView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
dummyView.backgroundColor = .red
shadowBackgroundView.addSubview(dummyView)
let addShadowButton = UIButton(frame: CGRect(x: 100, y: 300, width: 140, height: 50))
addShadowButton.backgroundColor = .blue
addShadowButton.setTitle("Add Shadow", for: .normal)
addShadowButton.addTarget(self, action: #selector(addShadow), for: .touchUpInside)
let removeShadowButton = UIButton(frame: CGRect(x: 100, y: 450, width: 140, height: 50))
removeShadowButton.backgroundColor = .blue
removeShadowButton.setTitle("Remove Shadow", for: .normal)
removeShadowButton.addTarget(self, action: #selector(removeShadow), for: .touchUpInside)
view.addSubview(addShadowButton)
view.addSubview(removeShadowButton)
}
#objc
func addShadow() {
let shadowLayer = CALayer()
shadowLayer.name = "ShadowLayer"
shadowLayer.shadowColor = UIColor.black.cgColor
shadowLayer.shadowOpacity = 1
shadowLayer.shadowOffset = .zero
shadowLayer.shadowRadius = 10
shadowLayer.shadowPath = UIBezierPath(rect: shadowBackgroundView.bounds).cgPath
// Otherwise the shadow will appear above the dummyView
shadowLayer.zPosition = -1
shadowBackgroundView.layer.addSublayer(shadowLayer)
}
#objc
func removeShadow() {
// Alternatively, you could also create the shadowLayer as a property, so you could call shadowLayer.removeFromSuperLayer()
shadowBackgroundView.layer.sublayers?.first { $0.name == "ShadowLayer" }?.removeFromSuperlayer()
}
}
As a Note, for the UITableViewCell, you wouldnt need to add a shadowBackgroundView, but you could add the shadowLayer directly to cell.view.layer, which serves as the backgroundView for the cell.contentView.

Answer 7

Swift 4.2
Just to add to the other answers, you could change the opacity through animation:
#IBAction func btnDidTap(_ sender: UICustomGestureRecognizer) {
guard let view = sender.view else {return}
if sender.state == .began {
UIView.animate(withDuration: 0.3,
animations: {
view.layer.shadowOpacity = 0
})
} else if sender.state == .ended {
UIView.animate(withDuration: 0.3,
animations: {
view.layer.shadowOpacity = 1
})
}
}