條碼上swift 4

Question

我想升級mi app到swift 4，但條形碼閱讀器不工作。

我已經隔離了條碼閱讀器代碼，但仍然無法工作。相機可以工作，但不會檢測條形碼。

代碼工作就好上迅速3 iOS的10

這是完整的代碼

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 
} 
} 

我在我的iPhone使用的是iOS 11，升級到公測9

有什麼想法？謝謝。

Answer 1

我想通了，但蘋果並沒有讓它變得如此明顯。代理AVCaptureMetadataOutputObjectsDelegate的回調函數已被重命名並且參數名稱不同！

所以，更換

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

到

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

我的視圖控制器後，現在這是之前掃描QR碼。它具有相同的參數，但第一個參數名稱不同。更改函數和參數名稱並構建/運行。

希望這會有所幫助！

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

到：

Answer 2

更改您的代碼後

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

一切再次工作。