didFinishProcessingPhotoSampleBuffer not Calling - ios

Question

I am trying to learn how to take and save photos using AVFoundation. I have currently been able to make a custom camera view with a button that is linked to an action to take a photo. When i click the button the delegate method is not being called.
Here is my ViewController.swift:
class ViewController: UIViewController, AVCapturePhotoCaptureDelegate{
#IBOutlet weak var camerView: UIView!
#IBOutlet weak var photoButton: UIButton!
var captureSession : AVCaptureSession?
var sessionOutput : AVCapturePhotoOutput?
var previewLayer : AVCaptureVideoPreviewLayer?
var photoSettings : AVCapturePhotoSettings?
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
previewLayer?.frame = (self.camerView?.bounds)!
previewLayer?.position = CGPoint(x: (self.camerView?.frame.width)! / 2, y: (self.camerView?.frame.height)!/2)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
//Capture Session
captureSession = AVCaptureSession()
let devices = AVCaptureDeviceDiscoverySession(deviceTypes: [.builtInDualCamera], mediaType: AVMediaTypeVideo, position: .back)
for device in (devices?.devices)! {
do {
let input = try AVCaptureDeviceInput(device: device)
if (captureSession?.canAddInput(input))! {
captureSession?.addInput(input)
}
if (captureSession?.canAddOutput(sessionOutput))! {
captureSession?.addOutput(sessionOutput)
}
previewLayer = AVCaptureVideoPreviewLayer()
previewLayer?.session = captureSession
self.camerView.layer.addSublayer(previewLayer!)
self.camerView.addSubview(photoButton)
captureSession?.startRunning()
} catch {
print("error occurred")
}
}
}
#IBAction func takePhoto(_ sender: UIButton) {
photoSettings = AVCapturePhotoSettings(format: [AVVideoCodecKey : AVVideoCodecJPEG])
photoSettings?.flashMode = .on
sessionOutput?.capturePhoto(with: photoSettings!, delegate: self)
}
//AVCapturePhotoCaptureDelegate Functions
func capture(_ captureOutput: AVCapturePhotoOutput, didFinishProcessingPhotoSampleBuffer photoSampleBuffer: CMSampleBuffer?, previewPhotoSampleBuffer: CMSampleBuffer?, resolvedSettings: AVCaptureResolvedPhotoSettings, bracketSettings: AVCaptureBracketedStillImageSettings?, error: Error?) {
print("PhotoSampleBuffer")
}
}
All i am trying to do in the didFinisheProcessingPhotoSampleBuffer method is just to print() so I know it is being called. I will figure out how to save later (unless someone can point me to a good resoure to learn this.)
Let me know if you need any other info!

Answer 1

The capturePhoto method (and therefore the delegate callback) is not being called because your sessionOutput variable is nil.
To fix this, instantiate the sessionOutput variable when it is declared:
var sessionOutput = AVCapturePhotoOutput()
Also, you'll need to remove the ? after the sessionOutput because it is no longer Optional.
sessionOutput.capturePhoto(with: photoSettings!, delegate: self)