捕获QR码的代码在Xcode8和Swift3中看起来效果不佳

Question

我正在尝试使用AVCaptureMetadataOutputObjectsDelegateSwift3和iOS 10 beta设备捕获QR码.

但是captureOutput当设备的相机实际捕获QR码时,不会调用功能.

有人有解决方案吗？如果是这样,请告诉我如何修复和正常工作.

谢谢,

import UIKit
import AVFoundation

class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

  override func viewDidLoad() {
    super.viewDidLoad()

    let mySession: AVCaptureSession! = AVCaptureSession()
    let devices = AVCaptureDevice.devices()
    var myDevice: AVCaptureDevice!

    for device in devices! {
      if((device as AnyObject).position == AVCaptureDevicePosition.back){
        myDevice = device as! AVCaptureDevice
      }
    }

    let myVideoInput = try! AVCaptureDeviceInput.init(device: myDevice)

    if mySession.canAddInput(myVideoInput) {
      mySession.addInput(myVideoInput)
    }

    let myMetadataOutput: AVCaptureMetadataOutput! = AVCaptureMetadataOutput()

    if mySession.canAddOutput(myMetadataOutput) {
      mySession.addOutput(myMetadataOutput)
      myMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
      myMetadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
    }

    let myVideoLayer = AVCaptureVideoPreviewLayer.init(session: mySession)
    myVideoLayer?.frame = self.view.bounds
    myVideoLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
    self.view.layer.addSublayer(myVideoLayer!)

    mySession.startRunning()
  }


  // MARK: - AVCaptureMetadataOutputObjectsDelegate

  // This function is not called despite capturing QR code  
  func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, from connection: AVCaptureConnection!) {
    if metadataObjects.count > 0 {
      let qrData: AVMetadataMachineReadableCodeObject  = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
      print("\(qrData.type)")
      print("\(qrData.stringValue)")

    }
  }

}

Answer 1

AVCaptureMetadataOutputObjectsDelegate在Swift 3中实现的方法头已经变成这样:

func captureOutput(_ captureOutput: AVCaptureOutput!,
                   didOutputMetadataObjects metadataObjects: [Any]!,
                   from connection: AVCaptureConnection!) {

[AnyObject]- > [Any],我还没有检查你代码的其他部分,但至少,你需要解决这个问题.