[Swift 4] バーコードリーダアプリのメタデータ取得について

前提・実現したいこと

iOSでバーコードリーダを作成しようと思い各所を参考にし、実装したのですが、
メタデータが取得できない状況です。

発生している問題・エラーメッセージ

画面は正常にカメラが開かれて、赤枠も表示されます。
しかし、バーコードからメタデータが読み取れていないようです。
ビルドは成功しています。

該当のソースコード

swift
1import UIKit
2import AVFoundation
3
4class ViewController: UIViewController, AVCapturePhotoCaptureDelegate {
5
6    // Connect as outlet
7    @IBOutlet weak var previewView: UIView!
8    
9    // Make instance
10    var captureSession = AVCaptureSession()
11    
12    // Make notification
13    let notification = NotificationCenter.default
14    
15    // Status for privacy and in-output
16    var authStatus:AuthorizedStatus = .authorized
17    var inOutStatus:InputOutputStatus = .ready
18
19    // Authorization Status
20    enum AuthorizedStatus {
21        case authorized
22        case notAuthorized
23        case failed
24    }
25    // InOut Status
26    enum InputOutputStatus {
27        case ready
28        case notReady
29        case failed
30    }
31    
32    let x: CGFloat = 0.1
33    let y: CGFloat = 0.4
34    let width: CGFloat = 0.8
35    let height: CGFloat = 0.2
36    
37    override func viewDidLoad(){
38        super.viewDidLoad()
39        // interrupt if processing session
40        guard !captureSession.isRunning else {
41            return
42        }
43        // privacy authorization for camera
44        cameraAuth()
45        
46        // Set InputOutput
47        setupInputOutput()
48        
49        // Check camera is ready
50        if (authStatus == .authorized)&&(inOutStatus == .ready) {
51            // Set previewLayer
52            setPreviewLayer()
53            // Start session
54            captureSession.startRunning()
55        } else {
56            // alert
57            showAlert(appName: "Camera")
58        }
59        
60    }
61    
62    override func viewWillAppear(_ animated: Bool) {
63        super.viewWillAppear(animated)
64        
65        if (captureSession.isRunning == false) {
66            captureSession.startRunning()
67        }
68    }
69    
70    override func viewWillDisappear(_ animated: Bool) {
71        super.viewWillDisappear(animated)
72        
73        if (captureSession.isRunning == true) {
74            captureSession.stopRunning()
75        }
76    }
77    
78    func cameraAuth(){
79        let status = AVCaptureDevice.authorizationStatus(for: AVMediaType.video)
80        switch status {
81        case .notDetermined:
82            AVCaptureDevice.requestAccess(for: AVMediaType.video,
83                                          completionHandler: { [unowned self] authorized in print("First Time", authorized.description)
84                                            if authorized {
85                                                self.authStatus = .authorized
86                                            } else {
87                                                self.authStatus = .notAuthorized
88                                            }})
89        case .restricted, .denied:
90            authStatus = .notAuthorized
91        case .authorized:
92            authStatus = .authorized
93        }
94    }
95    
96    func setupInputOutput(){
97        // Set resolution
98        // captureSession.sessionPreset = AVCaptureSession.Preset.
99        
100        // Set input
101        do {
102            // Obtain devise
103            let devise = AVCaptureDevice.default(
104                AVCaptureDevice.DeviceType.builtInWideAngleCamera,
105                for: AVMediaType.video,
106                position: AVCaptureDevice.Position.back
107            )
108            
109            // where to input
110            let input = try AVCaptureDeviceInput(device: devise!)
111            if captureSession.canAddInput(input){
112                captureSession.addInput(input)
113            } else {
114                print("Failed to add input to session")
115                return
116            }
117        } catch let err as NSError {
118            print("Camera doesn't exist (err)")
119            return
120        }
121        
122        // Set output
123        let metadataOutput = AVCaptureMetadataOutput()
124        if captureSession.canAddOutput(metadataOutput) {
125            captureSession.addOutput(metadataOutput)
126            metadataOutput.setMetadataObjectsDelegate((self as? AVCaptureMetadataOutputObjectsDelegate), queue: DispatchQueue.main)
127            metadataOutput.metadataObjectTypes = [.ean13]
128            metadataOutput.rectOfInterest = CGRect(x: y, y: 1 - x - width, width: height, height: width)
129        } else {
130            print("Failed to add output to session")
131            return
132        }
133    }
134    
135    func setPreviewLayer(){
136        // Make previewLayer
137        let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
138        previewLayer.frame = view.layer.bounds
139        previewLayer.videoGravity = AVLayerVideoGravity.resizeAspect
140        
141        // Add preview
142        previewView.layer.addSublayer(previewLayer)
143        
144        // Add red-frame
145//        let detectionArea = UIView()
146//        detectionArea.frame = CGRect(x: view.frame.size.width * x, y: view.frame.size.height * y, width: view.frame.size.width * width, height: view.frame.size.height * height)
147//        detectionArea.layer.borderColor = UIColor.red.cgColor
148//        detectionArea.layer.borderWidth = 3
149//        view.addSubview(detectionArea)
150    }
151    
152    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection){
153        for metadata in metadataObjects as! [AVMetadataMachineReadableCodeObject] {
154            // check whether it's barcode
155            if metadata.type == AVMetadataObject.ObjectType.ean13 {
156                if metadata.stringValue != nil {
157                    print(metadata.stringValue!)
158                }
159            }
160            print("metadataOutput called")
161            
162            // metadata
163            print(metadata.type)
164            print(metadata.stringValue!)
165        }
166    }
167    
168    func showAlert(appName: String){
169        let aTitle = "privacy authorization for " + appName
170        let aMessage = "Please authorize by Setting>Privacy> " + appName
171        let alert = UIAlertController(title: aTitle, message: aMessage, preferredStyle: .alert)
172        
173        // OK(nothing)
174        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
175        
176        // Open Setting
177        alert.addAction(UIAlertAction(title: "Open Setting", style: .default, handler: { action in UIApplication.shared.open(URL(string: UIApplication.openSettingsURLString)!, options: [:], completionHandler: nil)}))
178        
179        // Display alert
180        self.present(alert, animated: false, completion: nil)
181    }
182}
183
184