Initializer error in Camera App for Xcode in Swift - swift

Question

I am building an app similar to a camera app in Xcode 10.1 using Swift. To do this, I have imported AVFoundation, and am close to finishing my code. However, upon this line of code
let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
which is in this block of code
func beginSession () {
do {
let captureDeviceInput = try AVCaptureDeviceInput( device: captureDevice!)
captureSession.addInput(captureDeviceInput)
} catch {
print(error.localizedDescription)
}
let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) {
self.previewLayer = self.previewLayer
self.view.layer.addSublayer(self.previewLayer)
self.previewLayer.frame = self.view.layer.frame
captureSession.startRunning()
let dataOutput = AVCaptureVideoDataOutput()
dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString): NSNumber(value: kCVPixelFormatType_32BGRA)] as [String : Any]
dataOutput.alwaysDiscardsLateVideoFrames = true
if captureSession.canAddOutput(dataOutput) {
captureSession.addOutput(dataOutput)
}
There appears an error that reads "Cannot invoke initializer for type 'AVCaptureVideoPreviewLayer' with an argument list of type '(session: AVCaptureSession, () -> ())'"
I don't exactly know what this means or how to fix it as I am relatively new to programming.

Answer 1

Where have you initialized captureSession?
Try something like this in your UIViewController:
var captureSession = AVCaptureSession()
var videoPreviewLayer: AVCaptureVideoPreviewLayer?
override func viewDidLoad() {
super.viewDidLoad()
beginSession()
}
func beginSession() {
// Get an instance of the AVCaptureDevice class to initialize a device object and provide the video as the media type parameter.
if let captureDevice = AVCaptureDevice.default(for: AVMediaType.video) {
do {
// Get an instance of the AVCaptureDeviceInput class using the previous device object.
let input = try AVCaptureDeviceInput(device: captureDevice)
// Set the input device on the capture session.
captureSession.addInput(input)
// Initialize a AVCaptureVideoDataOutput object and set it as the output device to the capture session.
let dataOutput = AVCaptureVideoDataOutput()
dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString): NSNumber(value: kCVPixelFormatType_32BGRA)] as [String : Any]
dataOutput.alwaysDiscardsLateVideoFrames = true
if captureSession.canAddOutput(dataOutput) {
captureSession.addOutput(dataOutput)
}
// Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
videoPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
videoPreviewLayer?.frame = self.view.layer.bounds // It may be best to setup an UIView outlet instead of using self.view
self.view.layer.addSublayer(videoPreviewLayer!)
// Start video capture.
captureSession.startRunning()
} catch {
// If any error occurs, simply print it out and don't continue any more.
print(error)
return
}
}
}
Hope it helps you!