Shadow layer not resizing when UIView frame changed

Question

Issue Image ScreenShot

class ViewController: UIViewController {
    var shadow : UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        shadow = UIView(frame: CGRect(x: 50,y: 50,width: 150,height:150))
        shadow.backgroundColor = .red
        shadow.dropShadow()
        self.view.addSubview(shadow)

    }

    @IBAction func btnActn(_ sender: Any) {self.shadow.frame = CGRect(x: 50,y: 50,width: 150,height: 50)

    }

}

extension UIView {
 func dropShadow(scale: Bool = true) {
        layer.masksToBounds = false
        layer.shadowColor = UIColor.black.cgColor
        layer.shadowOpacity = 0.5
        layer.shadowOffset = CGSize(width: 1, height: 1)
        layer.shadowRadius = 2
        layer.shadowPath = UIBezierPath(rect: bounds).cgPath
        layer.shouldRasterize = true
        layer.rasterizationScale = scale ? UIScreen.main.scale : 1
    }

}

Shadow layer not resizing when UIView frame changed, how to change equal to the frame size, this is my whole code of UIviewcontroller

Answer 1

You have many ways to do that:

First: In 'viewWillLayoutSubviews' method, you have to call your shadow method like this. so whenever you changed the frame then you have not worry about layers. This method will auto call whenever you have changed the view:-

override func viewWillLayoutSubviews() {
    shadow.dropShadow()
}

Second: When you are going to re-frame you view size then you have to set "true" for "autoresizesSubviews" like this:

@IBAction func btnActn(_ sender: Any) {
        self.shadow.frame = CGRect(x: 50,y: 50,width: 150,height: 50)
        self.shadow.autoresizesSubviews = true
    }

Answer 2

Before calling dropShadow, first, try to call layoutIfNeeded

        @IBAction func btnActn(_ sender: Any) {
          self.shadow.frame = CGRect(x: 50,y: 50,width: 150,height: 50)
          self.shadow.layoutIfNeeded()
          self.shadow.dropShadow()
        }