今天會介紹 使用 AVCaptureMetadataOutput 物件辨識 QRCode
前幾天介紹的 AVCaptureMetadataOutputObjectsDelegate 裡的委派方法 metadataOutout 會被呼叫

• 定義 metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) function

  unc metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
  
  if let metadataObject = metadataObjects.first {
  
  	// AVMetadataMachineReadableCodeObject 是從 Output 擷取到 Barcode 的內容
  	guard let readableObject = metadataObject as? AVMetadataMachineReadableCodeObject else { return }
  
  	for subView in scanQRCodeView.subviews{
  
  		if subView.layer.name == "blackBackgroundView" {
  
  			UIView.animate(withDuration: 0.5, animations: {
  				subView.alpha = 0
  			}) { (bool) in
  
  				subView.removeFromSuperview()
  
  				// 將讀取到的內容轉成字串
  				guard let stringValue = readableObject.stringValue else { return }
  				self.qrcodeString = stringValue
  
  				// 以 Alert 的方式判別是否要開啟連結
  				self.showAlertWith(title: "", message: "\(self.qrcodeString.description)", vc: self, confirmTitle: "Yes", cancelTitle: "No", confirm: {
  
  					// 開啟連結
  					if let url = URL(string: self.qrcodeString) {
  						if self.qrcodeString.contains("http") || self.qrcodeString.contains("https") {
  							UIApplication.shared.open(url, options: [:], completionHandler: nil)
  						}
  						else {
  							let newURL = URL(string: "https://\(self.qrcodeString.description)")
  							UIApplication.shared.open(newURL!, options: [:], completionHandler: nil)
  						}
  					}
  				}, cancel: {
  					self.scanQRCodeBlackView()
  				})
  			}
  		}
  	}
  }
  
  ``
  
  

明天將會介紹 把常用的功能寫成一個方便呼叫的 function，並以 extension 的方式加在專案底下

GitHub - AVCaptureVideoPreviewLayerDemo