后置摄像头在 Swift 中不起作用
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【中文标题】后置摄像头在 Swift 中不起作用【英文标题】：Back camera doesn't really work in Swift 【发布时间】：2017-08-25 19:27:02 【问题描述】：我正在尝试在我的应用上创建自定义相机。真的很简单，我想拍一张照片，然后把抓到的图片发给下一个视图控制器。不过不知道为什么，用前置摄像头拍照的时候摄像头还可以，但是用后置摄像头就不行了。
当我按下按钮拍照时，可能会有 7 秒的延迟，应用程序两次崩溃。
这是我的代码：
var captureSession = AVCaptureSession()
var backCamera: AVCaptureDevice?
var frontCamera: AVCaptureDevice?
var currentCamera: AVCaptureDevice?
var photoOutput: AVCapturePhotoOutput?
var cameraPreviewLayer: AVCaptureVideoPreviewLayer?
var image: UIImage?
override func viewDidLoad()
super.viewDidLoad()
setupCaptureSession()
setupDevice()
setupInputOutput()
setupPreviewLayer()
startRunningCaptureSession()
func setupCaptureSession()
captureSession.sessionPreset = AVCaptureSession.Preset.photo
func setupDevice()
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [AVCaptureDevice.DeviceType.builtInWideAngleCamera], mediaType: .video, position: AVCaptureDevice.Position.unspecified)
let devices = deviceDiscoverySession.devices
for device in devices
if device.position == AVCaptureDevice.Position.back
backCamera = device
else if device.position == AVCaptureDevice.Position.front
frontCamera = device
currentCamera = backCamera
func setupInputOutput()
do
let captureDeviceInput = try AVCaptureDeviceInput(device: currentCamera!)
captureSession.addInput(captureDeviceInput)
photoOutput = AVCapturePhotoOutput()
if #available(ios 11.0, *)
photoOutput?.setPreparedPhotoSettingsArray([AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])], completionHandler: nil)
else
// Fallback on earlier versions
photoOutput?.setPreparedPhotoSettingsArray([AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecJPEG])], completionHandler: nil)
captureSession.addOutput(photoOutput!)
catch
print(error)
func setupPreviewLayer()
cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
cameraPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
cameraPreviewLayer?.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
cameraPreviewLayer?.frame = CGRect(x: 0, y: 0, width: self.cameraView.frame.size.width, height: self.cameraView.frame.size.height)
cameraView.layer.addSublayer(cameraPreviewLayer!)
//self.view.layer.insertSublayer(cameraPreviewLayer!, at: 0)
func startRunningCaptureSession()
captureSession.startRunning()
@IBAction func switchCameraAction(_ sender: Any)
swapCamera()
/// Swap camera and reconfigures camera session with new input
fileprivate func swapCamera()
// Get current input
guard let input = captureSession.inputs[0] as? AVCaptureDeviceInput else return
// Begin new session configuration and defer commit
captureSession.beginConfiguration()
defer captureSession.commitConfiguration()
// Create new capture device
var newDevice: AVCaptureDevice?
if input.device.position == .back
newDevice = captureDevice(with: .front)
isFront = true
else
newDevice = captureDevice(with: .back)
isFront = false
// Create new capture input
var deviceInput: AVCaptureDeviceInput!
do
deviceInput = try AVCaptureDeviceInput(device: newDevice!)
catch let error
print(error.localizedDescription)
return
// Swap capture device inputs
captureSession.removeInput(input)
captureSession.addInput(deviceInput)
fileprivate func captureDevice(with position: AVCaptureDevice.Position) -> AVCaptureDevice?
let devices = AVCaptureDevice.DiscoverySession(deviceTypes: [AVCaptureDevice.DeviceType.builtInWideAngleCamera], mediaType: .video, position: AVCaptureDevice.Position.unspecified).devices
for device in devices
if device.position == position
return device
return nil
func crop(_ image: UIImage, withWidth width: Double, andHeight height: Double) -> UIImage?
if let cgImage = image.cgImage
let contextImage: UIImage = UIImage(cgImage: cgImage)
let contextSize: CGSize = contextImage.size
var posX: CGFloat = 0.0
var posY: CGFloat = 0.0
var cgwidth: CGFloat = CGFloat(width)
var cgheight: CGFloat = CGFloat(height)
// See what size is longer and create the center off of that
if contextSize.width > contextSize.height
posX = ((contextSize.width - contextSize.height) / 2)
posY = 0
cgwidth = contextSize.height
cgheight = contextSize.height
else
posX = 0
posY = ((contextSize.height - contextSize.width) / 2)
cgwidth = contextSize.width
cgheight = contextSize.width
let rect: CGRect = CGRect(x: posX, y: posY, width: cgwidth, height: cgheight)
// Create bitmap image from context using the rect
var croppedContextImage: CGImage? = nil
if let contextImage = contextImage.cgImage
if let croppedImage = contextImage.cropping(to: rect)
croppedContextImage = croppedImage
// Create a new image based on the imageRef and rotate back to the original orientation
if let croppedImage:CGImage = croppedContextImage
let image: UIImage = UIImage(cgImage: croppedImage, scale: image.scale, orientation: image.imageOrientation)
return image
return nil
@IBAction func takePhotoAction(_ sender: Any)
var settingsCamera = AVCapturePhotoSettings()
let previewPixelType = settingsCamera.availablePreviewPhotoPixelFormatTypes.first
settingsCamera.flashMode = .off
if isFront == false && hasFlash
settingsCamera.flashMode = .on
let previewFormat = [kCVPixelBufferPixelFormatTypeKey as String: previewPixelType,
kCVPixelBufferWidthKey as String: 160,
kCVPixelBufferHeightKey as String: 160]
settingsCamera.previewPhotoFormat = previewFormat
photoOutput?.capturePhoto(with: settingsCamera, delegate: self)
extension UploadViewController: AVCapturePhotoCaptureDelegate
func photoOutput(_ captureOutput: AVCapturePhotoOutput, didFinishProcessingPhoto photoSampleBuffer: CMSampleBuffer?, previewPhoto previewPhotoSampleBuffer: CMSampleBuffer?, resolvedSettings: AVCaptureResolvedPhotoSettings, bracketSettings: AVCaptureBracketedStillImageSettings?, error: Error?)
if let error = error
print("error occure : \(error.localizedDescription)")
if let sampleBuffer = photoSampleBuffer,
let previewBuffer = previewPhotoSampleBuffer,
let dataImage = AVCapturePhotoOutput.jpegPhotoDataRepresentation(forJPEGSampleBuffer: sampleBuffer, previewPhotoSampleBuffer: previewBuffer)
let dataProvider = CGDataProvider(data: dataImage as CFData)
let cgImageRef: CGImage! = CGImage(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: .defaultIntent)
var orientation = UIImageOrientation(rawValue: 0)
if isFront
orientation = UIImageOrientation.leftMirrored
else
orientation = UIImageOrientation.right
let image = UIImage(cgImage: cgImageRef, scale: 1.0, orientation: orientation!)
// var flippedImage = UIImage(CGImage: picture.CGImage!, scale: picture.scale, orientation: .leftMirrored)
let timage = crop(image, withWidth: 100, andHeight: 100)
let photoSecondVC = self.storyboard?.instantiateViewController(withIdentifier: "uploadSecondVC") as! UploadSecondViewController
photoSecondVC.imageData = timage!
photoSecondVC.isFront = isFront
self.navigationController?.pushViewController(photoSecondVC, animated: false)
else
print("some error here")
这是我在App崩溃时出现的（不知道有没有链接）：
2017-08-25 16:50:36.125052+0200 Fitshare[93231:3349636] 无法在 (UITabBarItem) 上设置 (keyPath) 用户定义的检查属性：[ setValue:forUndefinedKey:]：此类不是键值编码- 符合键 keyPath。 2017-08-25 16:50:36.125584+0200 Fitshare [93231:3349636] 无法在 (UITabBarItem) 上设置 (keyPath) 用户定义的检查属性：[setValue:forUndefinedKey:]：此类不符合键值编码关键keyPath。 2017-08-25 16:50:36.300650+0200 Fitshare[93231:3349636] [MC] 延迟加载 NSBundle MobileCoreServices.framework 2017-08-25 16:50:36.302462+0200 Fitshare[93231:3349636] [MC] 加载 MobileCoreServices.framework 2017-08-25 16:50:36.311211+0200 Fitshare[93231:3349636] [MC] systemgroup.com.apple.configurationprofiles 路径的系统组容器是 /Users/kevinboirel/Library/Developer/CoreSimulator/Devices/B48E7503-47C0 -4A75-AC5C-C3DEF6CC8507/data/Containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2017-08-25 16:50:36.363022+0200 Fitshare[93231:3349636] [Snapshotting] 对至少未渲染一次的视图（0x7fbb38f2b0c0，Fitshare.ALThreeCircleSpinner）进行快照需要 afterScreenUpdates：YES。 2017-08-25 16:50:36.469416+0200 Fitshare[93231:3349636] +[CATransaction 同步] 在事务中调用 2017-08-25 16:50:36.469800+0200 Fitshare[93231:3349636] +[CATransaction 同步] 在事务中调用
奇怪的事实是我在 XCode 中有这个消息错误：
【问题讨论】：
崩溃发生时控制台的输出是什么？ 我编辑了我的代码 ;) 我遇到了这种问题，这是由于内存消耗造成的。设备无法处理它并且首先与 XCode 断开连接（没有响应），然后有时会崩溃。crop() 和 photoOutput() 的所有相关内容与 CFData 等都是 CPU 消耗的。如果不使用，还有问题吗？
可以用非Beta XCode版本和iOS版本来检查吗？但很明显，后置摄像头而不是前置摄像头的问题表明存在内存问题（拍摄的照片会更大）。如果你评论了if let sampleBuffer = photoSampleBuffer,的所有代码，你还有问题吗？你能发到UploadSecondViewController吗？
【参考方案1】：
您需要两个协议委托，它们是：UIImagePickerControllerDelegate 和 UINavigationControllerDelegate
// MARK: - Global Declaration
@IBOutlet var imgProfile: UIImageView!
var imagePicker = UIImagePickerController()
// MARK: - Camera Methods
func PickingImageFromCamera()
let picker = UIImagePickerController()
picker.delegate = self
picker.allowsEditing = false
picker.sourceType = .camera
picker.cameraCaptureMode = .photo
present(picker, animated: true, completion: nil)
//----------------------------------
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [String : Any])
if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage
imgProfile.contentMode = .scaleToFill
imgProfile.image = pickedImage
dismiss(animated: true, completion: nil)
//----------------------------------
func imagePickerControllerDidCancel(_ picker: UIImagePickerController)
dismiss(animated: true, completion: nil)
//----------------------------------
我认为这段代码会对你有所帮助...
【讨论】：
以上代码用两侧摄像头（前置摄像头和第二个摄像头）测试。但是当您选择视频模式时，应用程序崩溃【参考方案2】：这是由于 UploadSecondViewController ...
我刚刚将发送到第二个 ViewController 的图片调整为更小的尺寸，应用程序现在可以了！
感谢您的回答！
【讨论】：
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