扫描条形码

1、iOS10之后 开启手机的摄像头需要在 Info.plist 里面添加两个键值对

Privacy - Photo Library Usage Description
Privacy - Camera Usage Description

2、 导入模块 AVFoundation、 遵守 AVCaptureMetadataOutputObjectsDelegate 协议

3、需要真机调用摄像头，不能用模拟器进行测试

 

代码：

import UIKit
import AVFoundation

class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    var scanRectView: UIView!
    var scanLine: UIImageView!
    var timer: Timer!
    
    var device: AVCaptureDevice!
    var input: AVCaptureDeviceInput!
    var output: AVCaptureMetadataOutput!
    var session: AVCaptureSession!
    var preview: AVCaptureVideoPreviewLayer!
    
    // 摄像头按钮
    lazy var cameraBtn: UIButton = {
        let cameraBtn = UIButton(frame: CGRect(x: 10, y: self.view.frame.height * 0.8, width: self.view.frame.width - 20, height: 44))
        cameraBtn.setTitle("扫一扫", for: .normal)
        cameraBtn.setTitleColor(UIColor.orange, for: .normal)
        cameraBtn.backgroundColor = UIColor.gray
        cameraBtn.addTarget(self, action: #selector(ViewController.fromCamera), for: .touchUpInside)
        
        return cameraBtn
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view.addSubview(self.cameraBtn)
    }
    
//    MARK: -life cycle
    
    // 通过摄像头扫描
    func fromCamera() {
        do {
            self.device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
            
            self.input = try AVCaptureDeviceInput(device: device)
            
            self.output = AVCaptureMetadataOutput()
            output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
            
            self.session = AVCaptureSession()
            if UIScreen.main.bounds.size.height < 500 {
                self.session.sessionPreset = AVCaptureSessionPreset640x480
            } else {
                self.session.sessionPreset = AVCaptureSessionPresetHigh
            }
            
            self.session.addInput(self.input)
            self.session.addOutput(self.output)
            
            self.output.metadataObjectTypes = [AVMetadataObjectTypeEAN8Code,
                                               AVMetadataObjectTypeEAN13Code,
                                               AVMetadataObjectTypeCode128Code,
                                               AVMetadataObjectTypeCode93Code]
            
            // 计算中间可探测区域
            let windowSize = UIScreen.main.bounds.size
            let scanSize = CGSize(width: windowSize.width * 3 / 4, height: windowSize.height * 3 / 4)
            var scanRect = CGRect(x: (windowSize.width - scanSize.width) / 2,
                                  y: (windowSize.height - scanSize.height) / 2,
                                  width: scanSize.width,
                                  height: scanSize.height)
            // 计算 rectOfInterset 注意x，y 交换位置
            scanRect = CGRect(x: scanRect.origin.y / windowSize.height,
                              y: scanRect.origin.x / windowSize.width, width: scanRect.size.height / windowSize.height, height: scanRect.size.width / windowSize.width)
            // 设置可探测区域
            self.output.rectOfInterest = scanRect
            
            self.preview = AVCaptureVideoPreviewLayer(session: self.session)
            self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill
            self.preview.frame = UIScreen.main.bounds
            self.view.layer.insertSublayer(self.preview, at: 0)
            
            // 添加中间的探测区域绿框
            self.scanRectView = UIView()
            self.view.addSubview(self.scanRectView)
            self.scanRectView.frame = CGRect(x: 0, y: 0, width: scanSize.width, height: 100)
            print(self.scanRectView.frame)
            self.scanRectView.center = CGPoint(x: UIScreen.main.bounds.midX, y: UIScreen.main.bounds.midY)
            self.scanRectView.layer.borderColor = UIColor.green.cgColor
            self.scanRectView.layer.borderWidth = 1
            
            // 添加扫描线
            self.scanLine = UIImageView()
            self.scanLine.frame = CGRect(x: 0, y: 0, width: self.scanRectView.frame.size.width, height: 5)
            scanLine.image = UIImage(named: "line3")
            // 添加扫描线图层
            self.scanRectView.addSubview(self.scanLine)
            // 创建定时器， 用于实现扫描线动画
            self.timer = Timer()
            timer = Timer.scheduledTimer(timeInterval: 4, target: self, selector: #selector(ViewController.moveScannerLayer(_:)), userInfo: nil, repeats: true)
            
            
            // 开始捕获
            self.session.startRunning()
            
            // 放大
            do {
                try self.device.lockForConfiguration()
            } catch _ {
                print("Error: lock For Cpnfuguration.")
            }
            self.device.videoZoomFactor = 1.5
            self.device.unlockForConfiguration()
        } catch _ {
            // 打印错误信息
            // 打印错误消息
            let alertControl = UIAlertController(title: "提醒", message: "请在 iPhone 的\"设置-隐私-相机\"选项中,允许本程序访问您的相机", preferredStyle: .alert)
            let cancelAction = UIAlertAction(title: "确定", style: .cancel, handler: nil)
            alertControl.addAction(cancelAction)
            self.present(alertControl, animated: true, completion: nil)
        }
    }
    
    // 让扫描线滚动
    func moveScannerLayer(_ timer: Timer) {
        self.scanLine.frame = CGRect(x: 0, y: 0, width: self.scanRectView.frame.size.width, height: 12)
        UIView.animate(withDuration: 2) {
            self.scanLine.frame = CGRect(x: self.scanLine.frame.origin.x,
                                         y: self.scanLine.frame.origin.y + self.scanRectView.frame.size.height - 10,
                                         width: self.scanLine.frame.width,
                                         height: self.scanLine.frame.height)
        }
    }

    
//    MARK: -AVCaptureMetadataOutputObjectsDelegate
    // 摄像头捕获
    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
        
        var stringValue: String?
        if metadataObjects.count > 0 {
            let metadataObject = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
            stringValue = metadataObject.stringValue
            if stringValue != nil {
                self.session.stopRunning()
            }
        }
        
        self.session.stopRunning()
        // 输出结果
        let alertController = UIAlertController(title: "二维码", message:  stringValue, preferredStyle: .alert)
        let okAction = UIAlertAction(title: "确定", style: .default) { (action) in
            // 继续扫描
            self.session.startRunning()
        }
        alertController.addAction(okAction)
        self.present(alertController, animated: true, completion: nil)
    }
    
    

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


}