掃描二維碼可是說是很常見的需求了，利用相機掃描出二維碼中的URL。主要用到的是AVFoundation框架。
首先要獲取手機的相機權限，在info.plist文件中添加兩個鍵值對Privacy - Photo Library Usage Description與Privacy - Camera Usage Description
代碼部分:
let alertAction = UIAlertController.init(title: "需要獲取相機權限", message: nil, preferredStyle: .actionSheet)
alertAction.addAction(UIAlertAction.init(title: "獲取相機權限", style: .default, handler: { (alertCamera) in
let picker:UIImagePickerController = UIImagePickerController()
picker.delegate = self
picker.sourceType = .camera
picker.allowsEditing = true
self.present(picker, animated: true, completion: nil)
}))
接著需要做一個掃描框:
掃描框
var lineImageView: UIImageView!
var lineImage: UIImage!
var overlayView: UIView!
var ratioView: UIView!
func createView() {
lineImage = UIImage.init(named: "scanqrcode_line")
lineImageView = UIImageView.init(image: lineImage)
lineImageView.frame = CGRect(x: (UIScreen.main.bounds.size.width - 240) * 0.5, y:100 - self.lineImage.size.height * 0.5, width: 240, height: self.lineImage.size.height)
self.view.addSubview(lineImageView)
self.lineImageView.layer.zPosition = 2
self.overlayView = UIView.init(frame: CGRect(x: 0 , y: 0 ,width: self.view.frame.size.width, height: self.view.frame.size.height))
self.overlayView.alpha = 0.5
self.overlayView.backgroundColor = UIColor.black
self.view.addSubview(self.overlayView)
self.overlayView.layer.zPosition = 2
self.ratioView = UIView.init(frame: CGRect(x: (UIScreen.main.bounds.size.width - 240) * 0.5 , y: 100 ,width: 240, height: 240))
self.ratioView.layer.borderColor = UIColor.lightGray.cgColor
self.ratioView.layer.borderWidth = 1
self.view.addSubview(self.ratioView)
self.ratioView.layer.zPosition = 2
let maskLayer: CAShapeLayer! = CAShapeLayer.init()
let path: CGMutablePath! = CGMutablePath()
// left
path.addRect(CGRect(x:0,y:0,width:self.ratioView.frame.origin.x,height:self.overlayView.frame.size.height))
// right
path.addRect(CGRect(x:self.ratioView.frame.origin.x + self.ratioView.frame.size.width,y:0,width:self.overlayView.frame.size.width - self.ratioView.frame.origin.x - self.ratioView.frame.size.width,height:self.overlayView.frame.size.height))
// top
path.addRect(CGRect(x:0,y:0,width:self.overlayView.frame.size.width,height:self.ratioView.frame.origin.y))
// bottom
path.addRect(CGRect(x:0,y:self.ratioView.frame.origin.y + self.ratioView.frame.size.height,width:self.overlayView.frame.size.width,height:self.overlayView.frame.size.height - self.ratioView.frame.origin.y + self.ratioView.frame.size.height))
maskLayer.path = path
self.overlayView.layer.mask = maskLayer
let cornerImg = UIImage.init(named: "scanqrcode_corner")
let cornerImgView = UIImageView.init(image: UIImage.init(named: "scanqrcode_corner"))
cornerImgView.frame = CGRect(x:(UIScreen.main.bounds.size.width - 240) * 0.5, y:100,width: (cornerImgView.image?.size.width)!,height:(cornerImgView.image?.size.height)!)
self.view.addSubview(cornerImgView)
cornerImgView.layer.zPosition = 2
let ratateImg = UIImage.init(cgImage: (cornerImg?.cgImage)!, scale: 1, orientation: UIImageOrientation.right)
let ratateImgView = UIImageView.init(image: ratateImg)
ratateImgView.frame = CGRect(x:(UIScreen.main.bounds.size.width - 240) * 0.5 + 240 - (cornerImg?.size.width)!, y:100 , width: (cornerImg?.size.width)!, height: (cornerImg?.size.height)!)
self.view.addSubview(ratateImgView)
ratateImgView.layer.zPosition = 2
self.downAnimate()
}
func downAnimate() {
UIView.animate(withDuration: 3, animations: {
self.lineImageView.frame = CGRect(x: (UIScreen.main.bounds.size.width - 240) * 0.5, y:340 - self.lineImage.size.height * 0.5,width: 240,height: self.lineImageView.frame.size.height)
}) { (finished) in
self.upAnimate()
}
}
func upAnimate() {
UIView.animate(withDuration: 3, animations: {
self.lineImageView.frame = CGRect(x: (UIScreen.main.bounds.size.width - 240) * 0.5, y:100 - self.lineImage.size.height * 0.5,width: 240,height: self.lineImageView.frame.size.height)
}) { (finished) in
self.downAnimate()
}
}
接下來是重頭戲部分，二維碼掃描:
// AVCaptureSession是AVFoundation的核心類,用于捕捉視頻和音頻,協調視頻和音頻的輸入和輸出流
var session: AVCaptureSession!
// 視頻預覽層
var preview: AVCaptureVideoPreviewLayer!
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.startReading()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
self.stopReading()
}
func startReading() {
// 獲取 AVCaptureDevice 實例
let device: AVCaptureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
do {
// 初始化輸入流
let input = try AVCaptureDeviceInput.init(device: device)
// 初始化session
self.session = AVCaptureSession()
self.session.sessionPreset = AVCaptureSessionPresetHigh
// 添加輸入設備到會話對象
self.session.addInput(input)
// 初始化輸出流
let output: AVCaptureMetadataOutput = AVCaptureMetadataOutput.init()
self.session.addOutput(output)
output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
// 條碼類型
output.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
// 創建輸出對象
self.preview = AVCaptureVideoPreviewLayer.init(session: session)
self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill
self.preview.frame = CGRect(x:0,y:0,width:self.view.frame.size.width,height:self.view.frame.size.height)
self.view.layer.addSublayer(self.preview)
// 開始會話
self.session.startRunning()
}catch{
print(error)
return
}
}
func stopReading() {
self.session.startRunning()
self.session = nil
}
需要遵循AVCaptureMetadataOutputObjectsDelegate協議,掃描結果要從代理方法中獲得:
//當AVCaptureMetadataOutput對象識別QR code將觸發該方法
func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
// 確認是否元數據對象數組是否不為nil并至少包含一個對象,如果為nil,顯示對應提示信息
if metadataObjects == nil || metadataObjects.count == 0 {
resultLabel.text = "二維碼錯誤"
}
// 獲取元數據
let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
if metadataObj.type == AVMetadataObjectTypeQRCode {
print(metadataObj.stringValue)
let alertAction = UIAlertController.init(title: "\(metadataObj.stringValue!)", message: nil, preferredStyle: .alert)
self.present(alertAction, animated: true, completion: nil)
}
}
掃描結果
其中遇到一個問題，掃描中會出現崩潰，最終是因為添加輸出流output需要在setMetadataObjectsDelegate之前進行,解決這個之后完美運行:
self.session.addOutput(output)
output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
