Question

我正在尝试为应用创建条形码读取器功能。为此，我无法获得任何相机设备。

我正在使用AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInDualCamera], mediaType: AVMediaType.video, position:. back)来获取设备列表。

我正在尝试从上述列表中获取第一台设备

但是它不会返回任何相机。

我还在info.plist

中添加了“隐私-相机使用说明”

       func viewDidLoad() {

            let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInDualCamera], mediaType: AVMediaType.video, position:. back)

            guard let captureDevice = deviceDiscoverySession.devices.first else{
            print("Failed to get the camera device")
            return
            }

       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 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: DispatchQueue.main)

            captureMetadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]



            //Initialize the video preview layer and add it as a subLayer to the viewPreview view

            videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)

            videoPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill

            videoPreviewLayer?.frame = view.layer.bounds

            view.layer.addSublayer(videoPreviewLayer!)



            //Start video capture.

            captureSession?.startRunning()

        } catch {

            // if any error occurs, print it out and don't continue any more

            print(error)

            return

        }
}

我希望它能启动相机；但是，它却给了我以下错误：

2019-05-05 16：17：46.609442-0500 BarCode [964：302791] [MC] systemgroup.com.apple.configurationprofiles路径的系统组容器为/ private / var / containers / Shared / SystemGroup / systemgroup。 com.apple.configurationprofiles

2019-05-05 16：17：46.609962-0500 BarCode [964：302791] [MC]从公共有效用户设置中读取。

无法获取摄像头设备。

Answer 1

可能就像错误所提到的那样。该设备没有任何.builtInDualCamera选项。

您可以尝试的普通相机类型是

let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back)

如果您确实需要.builtInDualCamera，则可以按照Apple文档的建议进行操作，该文档将实施if...else检查后备计划。

Building a Camera App

无法为iOS打开相机

1 个答案: