UIViewController can't override method from it's superclass - ios

Question

I am actually experimenting with the Vision Framework.
I have simply an UIImageView in my Storyboard and my class is from type UIViewController.
But when I try to override viewDidAppear(_ animated: Bool) I get the error message: Method does not override any method from its superclass
Do anyone know what the issue is? Couldn't find anything that works for me...

Answer 1

So after looking at the code, you are declaring a new class called UIViewController. Maybe you meant extension instead of class.
That's the reason the compiler could not find the method because you overwrote it by creating that new class called UIViewController.
replace
class UIViewController {
with
extension UIViewController {

Answer 2

This is my complete code:
import UIKit
import Vision
class ViewController: UIViewController {
#IBOutlet weak var imageView: UIImageView!
var imageOrientation = CGImagePropertyOrientation(.up)
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if let image = UIImage(named: "group") {
imageView.image = image
imageView.contentMode = .scaleAspectFit
imageOrientation = CGImagePropertyOrientation(image.imageOrientation)
guard let cgImage = image.cgImage else {return}
setupVision(image: cgImage)
}
}
private func setupVision (image: CGImage) {
let faceDetectionRequest = VNDetectFaceRectanglesRequest(completionHandler: self.handelFaceDetectionRequest)
let imageRequestHandler = VNImageRequestHandler(cgImage: image, orientation: imageOrientation, options: [:])
do {
try imageRequestHandler.perform([faceDetectionRequest])
}catch let error as NSError {
print(error)
return
}
}
private func handelFaceDetectionRequest (request: VNRequest?, error: Error?) {
if let requestError = error as NSError? {
print(requestError)
return
}
guard let image = imageView.image else {return}
guard let cgImage = image.cgImage else {return}
let imageRect = self.determineScale(cgImage: cgImage, imageViewFrame: imageView.frame)
self.imageView.layer.sublayers = nil
if let results = request?.results as? [VNFaceObservation] {
for observation in results {
let faceRect = convertUnitToPoint(originalImageRect: imageRect, targetRect: observation.boundingBox)
let emojiRect = CGRect(x: faceRect.origin.x, y: faceRect.origin.y - 5, width: faceRect.size.width + 5, height: faceRect.size.height + 5)
let textLayer = CATextLayer()
textLayer.string = "🦸‍♂️"
textLayer.fontSize = faceRect.width
textLayer.frame = emojiRect
textLayer.contentsScale = UIScreen.main.scale
self.imageView.layer.addSublayer(textLayer)
}
}
}
}
and:
import UIKit
class UIViewController {
public func convertUnitToPoint (originalImageRect: CGRect, targetRect: CGRect) -> CGRect {
var pointRect = targetRect
pointRect.origin.x = originalImageRect.origin.x + (targetRect.origin.x * originalImageRect.size.width)
pointRect.origin.y = originalImageRect.origin.y + (1 - targetRect.origin.y - targetRect.height)
pointRect.size.width *= originalImageRect.size.width
pointRect.size.height *= originalImageRect.size.height
return pointRect
}
public func determineScale (cgImage: CGImage, imageViewFrame: CGRect) -> CGRect {
let originalWidth = CGFloat(cgImage.width)
let originalHeigth = CGFloat(cgImage.height)
let imageFrame = imageViewFrame
let widthRatio = originalWidth / imageFrame.width
let heigthRatio = originalHeigth / imageFrame.height
let scaleRatio = max(widthRatio, heigthRatio)
let scaledImageWidth = originalWidth / scaleRatio
let scaledImageHeigth = originalHeigth / scaleRatio
let scaledImageX = (imageFrame.width - scaledImageWidth) / 2
let scaledImageY = (imageFrame.height - scaledImageHeigth) / 2
return CGRect(x: scaledImageX, y: scaledImageY, width: scaledImageWidth, height: scaledImageHeigth)
}
}
extension CGImagePropertyOrientation {
init(_ orientation: UIImage.Orientation) {
switch orientation {
case .up: self = .up
case .upMirrored: self = .upMirrored
case .down: self = .down
case .downMirrored: self = .downMirrored
case .right: self = .right
case .rightMirrored: self = .rightMirrored
default: self = .up
}
}
}
The first code snipped is from the ViewController file