iOS add / remove shadow from a view

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          


        

Answer 1

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 2

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 3

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 4

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 5

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 6

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