Swift 2 Extra argument error in call viewdidload image - ios

Question

i'm updating my app to Swift 2 with Xcode 7. this is my code of a ViewController viewDidLoad.
override func viewDidLoad() {
super.viewDidLoad()
// Get an instance of the AVCaptureDevice class to initialize a device object and provide the video
// as the media type parameter.
let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
// Get an instance of the AVCaptureDeviceInput class using the previous device object.
var error:NSError?
let input: AnyObject! = AVCaptureDeviceInput.deviceInputWithDevice(captureDevice, error: &error)
if (error != nil) {
// If any error occurs, simply log the description of it and don't continue any more.
print("\(error?.localizedDescription)")
return
}
// Initialize the captureSession object.
captureSession = AVCaptureSession()
// Set the input device on the capture session.
captureSession?.addInput(input as! AVCaptureInput)
// Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
let captureMetadataOutput = AVCaptureMetadataOutput()
captureSession?.addOutput(captureMetadataOutput)
// Set delegate and use the default dispatch queue to execute the call back
captureMetadataOutput.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
captureMetadataOutput.metadataObjectTypes = supportedBarCodes
// Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
videoPreviewLayer?.frame = view.layer.bounds
view.layer.addSublayer(videoPreviewLayer!)
// Start video capture.
captureSession?.startRunning()
// Move the message label to the top view
view.bringSubviewToFront(messageLabel)
// Initialize QR Code Frame to highlight the QR code
qrCodeFrameView = UIView()
qrCodeFrameView?.layer.borderColor = UIColor.greenColor().CGColor
qrCodeFrameView?.layer.borderWidth = 2
view.addSubview(qrCodeFrameView!)
view.bringSubviewToFront(qrCodeFrameView!)
}
on line
let input: AnyObject! = AVCaptureDeviceInput.deviceInputWithDevice(captureDevice, error: &error)
i get the error Extra argument error in call. I already tried with the method do{} and catch{} but it didn't work, i always get that error.
How can i fix that? Thanks

Answer 1

Swift 2 introduced new error handling. To solve the problem you are having, you need to catch the error instead of passing an NSError object to the AVCaptureDevice method:
override func viewDidLoad() {
super.viewDidLoad()
do {
let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
let input = try AVCaptureDeviceInput(device: captureDevice)
// Do the rest of your work...
} catch let error as NSError {
// Handle any errors
print(error)
}
}
For a more in-depth explanation have a look at this article:
Error Handling in Swift 2.0

Answer 2

it doesn't look like that type method exists anymore on AVCaptureDeviceInput, see -> https://developer.apple.com/library/prerelease/ios/documentation/AVFoundation/Reference/AVCaptureDeviceInput_Class/index.html#//apple_ref/swift/cl/c:objc(cs)AVCaptureDeviceInput
(it looks like you probably want to use init(device:))
...as a handy tip: anytime you're browsing the developer library via the web, if you're not sure if you're seeing the latest 'prerelease' version of the documentation check the URL -> add '/prerelease' between 'library' and '/ios' if necessary :)