Question

我有这个代码，可以用来从唱片黑胶唱片中读取条形码，然后，我尝试根据称为Discogs的网站上条形码的结果来获取信息。我已经在此网站上创建了一个应用程序，但这是必需的，但是每次阅读完条形码后，我的应用程序都会崩溃。我可以读取条形码（获取其中的数字），然后将其viewcontroller退回到mainVC，在那里应显示结果，但我的应用在崩溃之前崩溃了... 我该怎么办？我正在使用alamofire

      func setupCamera(){
        session = AVCaptureSession()
        let videoCaptureDevice = AVCaptureDevice.default(for: AVMediaType.video)
        let videoInput : AVCaptureDeviceInput!

        do {
            videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice!)
        } catch {
            return
        }

        if (session.canAddInput(videoInput)){
            session.addInput(videoInput)
        } else {
            scanningNotPossible()
        }

        // Create output object.
        let metadataOutput = AVCaptureMetadataOutput()

        // Add output to the session.
        if (session.canAddOutput(metadataOutput)) {
            session.addOutput(metadataOutput)

            // Send captured data to the delegate object via a serial queue.
            metadataOutput.setMetadataObjectsDelegate(self, queue: .main)

            // Set barcode type for which to scan: EAN-13.
            metadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.ean13]

        } else {
            scanningNotPossible()
        }

        previewLayer = AVCaptureVideoPreviewLayer(session: session);
        previewLayer.frame = view.layer.bounds;
        previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill;
        view.layer.addSublayer(previewLayer);

        // Begin the capture session.

        session.startRunning()

    }

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

        if let metadataObject = metadataObjects.first {
            guard let readableObject = metadataObject as? AVMetadataMachineReadableCodeObject else { return }
            guard let stringValue = readableObject.stringValue else { return }
            AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
            found(code: stringValue)
        }

       // dismiss(animated: true)
    }

        func barcodeDetected(code: String) {

        // Let the user know we've found something.
        let alert = UIAlertController(title: "Found a Barcode!", message: code, preferredStyle: UIAlertController.Style.alert)
        let theAction = UIAlertAction(title: "Search", style: .default){ (action: UIAlertAction!) in

            // Remove the spaces.
            let trimmedCode = code.trimmingCharacters(in: .whitespaces)

            // EAN or UPC?
            // Check for added "0" at beginning of code.

            let trimmedCodeString = "\(trimmedCode)"
            var trimmedCodeNoZero: String

            if trimmedCodeString.hasPrefix("0") && trimmedCodeString.count > 1 {
                trimmedCodeNoZero = String(trimmedCodeString.dropFirst())

                // Send the doctored UPC to DataService.searchAPI()
                DataService.searchAPI(codeNumber: trimmedCodeNoZero)
            } else {

                // Send the doctored EAN to DataService.searchAPI()
                DataService.searchAPI(codeNumber: trimmedCodeString)
            }
            print("popopop")
            self.navigationController?.popViewController(animated: true)
        }


        alert.addAction(theAction)
        self.present(alert, animated: true, completion: nil)
    }

    import Foundation
import Alamofire
import SwiftyJSON

class DataService {

    static let dataService = DataService()

    private(set) var ALBUM_FROM_DISCOGS = ""
    private(set) var YEAR_FROM_DISCOGS = ""

    static func searchAPI(codeNumber: String) {

        // The URL we will use to get out album data from Discogs
        let discogsURL = "\(DISCOGS_AUTH_URL)\(codeNumber)&?barcode&key=\(DISCOGS_KEY)&secret=\(DISCOGS_SECRET)"

        Alamofire.request(discogsURL)
            .responseJSON { response in

                var json = JSON(response.result.value!)

                let albumArtistTitle = "\(json["results"][0]["title"])"
                let albumYear = "\(json["results"][0]["year"])"

                self.dataService.ALBUM_FROM_DISCOGS = albumArtistTitle
                self.dataService.YEAR_FROM_DISCOGS = albumYear

                // Post a notification to let AlbumDetailsViewController know we have some data.
                NotificationCenter.default.post(name: NSNotification.Name(rawValue: "AlbumNotification"), object: nil)
        }
    }

}

日志错误：

> 2019-04-26 17:35:21.791189-0300 Discogs Barcode Example[1852:598955] -[Discogs_Barcode_Example.AlbumDetaisViewController setLabels]: unrecognized selector sent to instance 0x10230a460
2019-04-26 17:35:21.793519-0300 Discogs Barcode Example[1852:598955] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Discogs_Barcode_Example.AlbumDetaisViewController setLabels]: unrecognized selector sent to instance 0x10230a460'
*** First throw call stack:
(0x2016c3518 0x20089e9f8 0x2015e0278 0x22d83bef8 0x2016c8d60 0x2016ca9fc 0x2016345bc 0x201634588 0x201633a7c 0x201633728 0x2015ad524 0x2016331d8 0x20201b814 0x100f1cb38 0x101358d78 0x101325708 0x10209b6f0 0x10209cc74 0x1020aa6fc 0x201654ec0 0x20164fdf8 0x20164f354 0x20384f79c 0x22d810b68 0x100f1b03c 0x2011158e0)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

[Discogs_Barcode_Example.AlbumDetaisViewController setLabels]：

似乎AlbumDetaisViewController已挂接到名为setLabels的操作方法上，并且您将其更改为其他名称，因此要么返回原始名称，要么清除IB的连接并使用新名称进行连接

尝试使用Alamofire访问API时，应用崩溃

1 个答案: