条码在迅速4

我正在尝试将mi应用程序升级到swift 4，但是条形码阅读器不工作。

我已经隔离了条码阅读器的代码，仍然不能正常工作。 相机工作，但它不检测条码。

代码在swift 3 iOS 10上工作得很好。

这是完整的代码

import AVFoundation import UIKit class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate { var captureSession: AVCaptureSession! var previewLayer: AVCaptureVideoPreviewLayer! override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = UIColor.black captureSession = AVCaptureSession() let videoCaptureDevice = AVCaptureDevice.default(for: AVMediaType.video) let videoInput: AVCaptureDeviceInput do { videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice!) } catch { return } if (captureSession.canAddInput(videoInput)) { captureSession.addInput(videoInput) } else { failed(); return; } let metadataOutput = AVCaptureMetadataOutput() if (captureSession.canAddOutput(metadataOutput)) { captureSession.addOutput(metadataOutput) metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main) metadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.ean8, AVMetadataObject.ObjectType.ean13, AVMetadataObject.ObjectType.pdf417] } else { failed() return } previewLayer = AVCaptureVideoPreviewLayer(session: captureSession); previewLayer.frame = view.layer.bounds; previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill; view.layer.addSublayer(previewLayer); captureSession.startRunning(); } func failed() { let ac = UIAlertController(title: "Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.", preferredStyle: .alert) ac.addAction(UIAlertAction(title: "OK", style: .default)) present(ac, animated: true) captureSession = nil } override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) if (captureSession?.isRunning == false) { captureSession.startRunning(); } } override func viewWillDisappear(_ animated: Bool) { super.viewWillDisappear(animated) if (captureSession?.isRunning == true) { captureSession.stopRunning(); } } func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) { captureSession.stopRunning() if let metadataObject = metadataObjects.first { let readableObject = metadataObject as! AVMetadataMachineReadableCodeObject; AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate)) found(code: readableObject.stringValue!); } dismiss(animated: true) } func found(code: String) { print(code) } override var prefersStatusBarHidden: Bool { return true } override var supportedInterfaceOrientations: UIInterfaceOrientationMask { return .portrait } } 

我在iPhone上使用iOS 11，升级到beta 9。

任何想法？ 谢谢。

Answer 1

我知道了，但苹果并没有这么明显。 代理AVCaptureMetadataOutputObjectsDelegate的callback函数已被重命名，参数名称不同！

所以，更换

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

至

 func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) 

之后，我的视图控制器现在正在扫描QR码。 它具有相同的参数，但第一个参数名称不同。 更改函数和参数名称并构build/运行。

希望这可以帮助！

Answer 2

从以下版本更改代码后：

 func metadataOutput(captureOutput: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {} 

至：

 func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {} 

一切再次运作。