錯誤：輸入'String！'沒有成員 '視頻'

Question

import UIKit 
import AVKit 

class ViewController: UIViewController { 
    override func viewDidLoad() { 
     super.viewDidLoad() 

//start camera 

     let captureSession = AVCaptureSession() 

     guard let captureDevice = 
      AVCaptureDevice.default(for: .video) else { return } 
     guard let input = try? AVCaptureDeviceInput(device: 
       captureDevice) else { return } 
     captureSession.addInput(input) 

     captureSession.startRunning() 
    } 
} 

我得到在此行中的誤差在（爲：。視頻）：

AVCaptureDevice.default(for: .video) else { return } 

Answer 1

方法

class func `default`(_ deviceType: AVCaptureDevice.DeviceType, 
      for mediaType: AVMediaType?, 
     position: AVCaptureDevice.Position) -> AVCaptureDevice? 

接受設備類型，這可以是：

AVCaptureDeviceTypeBuiltInMicrophone 
AVCaptureDeviceTypeBuiltInWideAngleCamera 
AVCaptureDeviceTypeBuiltInTelephotoCamera 
AVCaptureDeviceTypeBuiltInDualCamera 
AVCaptureDeviceTypeBuiltInDuoCamera 

Answer 2

我想我已經想通了出。我一直在尋找的文件是對的Xcode 9.你需要的是率先導入AVFoundation，然後使用此功能：

class func defaultDevice(withDeviceType deviceType: AVCaptureDeviceType!, 
             mediaType: String!, 
              position: AVCaptureDevicePosition) -> AVCaptureDevice! 

https://developer.apple.com/documentation/avfoundation/avcapturedevice/2361508-default?changes=latest_minor

例如：

let c = AVCaptureDevice.defaultDevice(withDeviceType: AVCaptureDeviceType.builtInTelephotCamer, 
              mediaType: AVMediaTypeVideo, 
              position: AVCaptureDevicePosition.front) 

Answer 3

我只是試圖將我的項目轉換爲Swift4。這對我有用。

device = AVCaptureDevice.default(for: AVMediaType.video) 

Answer 4

用AVMediaTypeVideo替換AVMediaType.video爲我工作。