swift - 如何正确设置委托(delegate)属性？ ( swift )

Question

我正在尝试将 SQLClient 实现到现有的 iOS 应用程序中。该应用程序是一个条形码阅读器，可通过 LAN 向数据库发出 INSERT。 SQLClient 的委托(delegate)属性必须设置为 NSObject 才能进行错误处理，但我在设置它时遇到了问题。 我的实现问题出现在最后一个方法中，found。

首先，Xcode 希望我向下转换为更具体的类型。在采纳 Xcode 的建议并将 client as Anyobject 转换后，我得到了 Ambigously use of delegate。

所以，简而言之，我需要帮助设置 SQLClient 的委托(delegate)属性，以便我可以触发插入。我愿意了解你们是否可以推荐资源或提供指导。

SQLClient --> https://github.com/martinrybak/SQLClient

//
//  QRScannerController.swift
//  QRCodeReader
//
//  Created by Simon Ng on 13/10/2016.
//  Copyright © 2016 AppCoda. All rights reserved.
//

import UIKit
import AVFoundation


class QRScannerController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    @IBOutlet var messageLabel:UILabel!
    @IBOutlet var topbar: UIView!

    var captureSession:AVCaptureSession?
    var videoPreviewLayer:AVCaptureVideoPreviewLayer?
    var qrCodeFrameView:UIView?

    let supportedCodeTypes = [AVMetadataObjectTypeUPCECode,
                        AVMetadataObjectTypeCode39Code,
                        AVMetadataObjectTypeCode39Mod43Code,
                        AVMetadataObjectTypeCode93Code,
                        AVMetadataObjectTypeCode128Code,
                        AVMetadataObjectTypeEAN8Code,
                        AVMetadataObjectTypeEAN13Code,
                        AVMetadataObjectTypeAztecCode,
                        AVMetadataObjectTypePDF417Code,
                        AVMetadataObjectTypeQRCode]

    override func viewDidLoad() {
        super.viewDidLoad()



        // Get an instance of the AVCaptureDevice class to initialize a device object and provide the video as the media type parameter.
        let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)

        do {
            // Get an instance of the AVCaptureDeviceInput class using the previous device object.
            let input = try AVCaptureDeviceInput(device: captureDevice)

            // Initialize the captureSession object.
            captureSession = AVCaptureSession()

            // Set the input device on the capture session.
            captureSession?.addInput(input)

            // Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
            let captureMetadataOutput = AVCaptureMetadataOutput()
            captureSession?.addOutput(captureMetadataOutput)

            // Set delegate and use the default dispatch queue to execute the call back
            captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
            captureMetadataOutput.metadataObjectTypes = supportedCodeTypes

            // Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
            videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
            videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
            videoPreviewLayer?.frame = view.layer.bounds
            view.layer.addSublayer(videoPreviewLayer!)

            // Start video capture.
            captureSession?.startRunning()

            // Move the message label and top bar to the front
            view.bringSubview(toFront: messageLabel)
            view.bringSubview(toFront: topbar)

            // Initialize QR Code Frame to highlight the QR code
            qrCodeFrameView = UIView()

            if let qrCodeFrameView = qrCodeFrameView {
                qrCodeFrameView.layer.borderColor = UIColor.green.cgColor
                qrCodeFrameView.layer.borderWidth = 2
                view.addSubview(qrCodeFrameView)
                view.bringSubview(toFront: qrCodeFrameView)
            }

        } catch {
            // If any error occurs, simply print it out and don't continue any more.
            print(error)
            return
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    // MARK: - AVCaptureMetadataOutputObjectsDelegate Methods

    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
        captureSession?.stopRunning()
        // Check if the metadataObjects array is not nil and it contains at least one object.
        if metadataObjects == nil || metadataObjects.count == 0 {
            qrCodeFrameView?.frame = CGRect.zero
            messageLabel.text = "No QR/barcode is detected"
            return
        }

        // Get the metadata object.
        let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject

        if supportedCodeTypes.contains(metadataObj.type) {
            // If the found metadata is equal to the QR code metadata then update the status label's text and set the bounds
            let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
            qrCodeFrameView?.frame = barCodeObject!.bounds

            if metadataObj.stringValue != nil {
                messageLabel.text = metadataObj.stringValue
                print(metadataObj.stringValue)
                found(code: metadataObj.stringValue)

            }
        }
    }

    func found(code: String) {
        print(code)
        /*
         Fire off the QR code to the database
        */
        let client = SQLClient.sharedInstance()!
        client.delegate = client.self

    }
}

Answer 1

这最终成为我遗漏的部分。

扩展QRScannerController:SQLClientDelegate { func error(_ 错误:字符串!，代码:Int32，严重性:Int32) { 打印(错误) } }