Adding inner shadow to top of UIView

Question

I looked up but I couldn't find how I can add an inner shadow to UIView, only top (from top to bottom) for Swift. What is the best way add inner circle in Swift?

Edit: I've found some questions & answers on SO however they are either in obj-c or looks so complicated. I was just looking for a more Swifty way, if there is any

What I want to achieve:

Answer 1

Here's a pure Swift version that I whipped up:

public class EdgeShadowLayer: CAGradientLayer {      public enum Edge {         case Top         case Left         case Bottom         case Right     }      public init(forView view: UIView,                 edge: Edge = Edge.Top,                 shadowRadius radius: CGFloat = 20.0,                 toColor: UIColor = UIColor.white,                 fromColor: UIColor = UIColor.black) {         super.init()         self.colors = [fromColor.cgColor, toColor.cgColor]         self.shadowRadius = radius          let viewFrame = view.frame          switch edge {             case .Top:                 startPoint = CGPoint(x: 0.5, y: 0.0)                 endPoint = CGPoint(x: 0.5, y: 1.0)                 self.frame = CGRect(x: 0.0, y: 0.0, width: viewFrame.width, height: shadowRadius)             case .Bottom:                 startPoint = CGPoint(x: 0.5, y: 1.0)                 endPoint = CGPoint(x: 0.5, y: 0.0)                 self.frame = CGRect(x: 0.0, y: viewFrame.height - shadowRadius, width: viewFrame.width, height: shadowRadius)             case .Left:                 startPoint = CGPoint(x: 0.0, y: 0.5)                 endPoint = CGPoint(x: 1.0, y: 0.5)                 self.frame = CGRect(x: 0.0, y: 0.0, width: shadowRadius, height: viewFrame.height)             case .Right:                 startPoint = CGPoint(x: 1.0, y: 0.5)                 endPoint = CGPoint(x: 0.0, y: 0.5)                 self.frame = CGRect(x: viewFrame.width - shadowRadius, y: 0.0, width: shadowRadius, height: viewFrame.height)         }     }      required public init?(coder aDecoder: NSCoder) {         fatalError("init(coder:) has not been implemented")     }    } 

To use it,

let topShadow = EdgeShadowLayer(forView: targetView, edge: .Top) targetView.layer.addSublayer(topShadow) 

Note that it defaults to a black-to-white gradient that's 20 points deep.

The full code, with a sample UIViewController that lets you toggle shadows on all four corners of a view, can be found at https://github.com/jrtibbetts/Tenebrae. I've also documented the EdgeShadowLayer pretty thoroughly.

Answer 2

I used implement inner shadow to UIView using Objective-C. I try to translate code into swift. Please forgive me for my poor swift syntax

you can call function below in UIView.didMoveToSuperview

func drawShadow() {     if nil == self.shadowLayer {         let size = self.frame.size         self.clipsToBounds = true         let layer: CALayer = CALayer()         layer.backgroundColor = UIColor.lightGrayColor().CGColor         layer.position = CGPointMake(size.width / 2, -size.height / 2 + 0.5)         layer.bounds = CGRectMake(0, 0, size.width, size.height)         layer.shadowColor = UIColor.darkGrayColor().CGColor         layer.shadowOffset = CGSizeMake(0.5, 0.5)         layer.shadowOpacity = 0.8         layer.shadowRadius = 5.0         self.shadowLayer = layer          self.layer.addSublayer(layer)     } }