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Barcode Scanner Camera View for SwiftUI
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| // | |
| // BarcodeScannerViewRepresentable.swift | |
| // | |
| // Created by Daven Gomes on 28/08/2020. | |
| // | |
| import SwiftUI | |
| import AVFoundation | |
| import UIKit | |
| struct BarcodeScannerViewRepresentable: UIViewRepresentable { | |
| enum ScanningState { | |
| case closed | |
| case cameraLoading | |
| case cameraLoaded | |
| case searching | |
| case failure | |
| } | |
| @Binding var currentPosition: AVCaptureDevice.Position | |
| @Binding var scanningState: BarcodeScannerViewRepresentable.ScanningState | |
| let onBarcodeScanned: (String) -> () | |
| class Coordinator: BarcodeScannerUIViewDelegate { | |
| @Binding var scanningState: BarcodeScannerViewRepresentable.ScanningState | |
| let onBarcodeScanned: (String) -> () | |
| init(scanningState: Binding<BarcodeScannerViewRepresentable.ScanningState>, | |
| onBarcodeScanned: @escaping (String) -> ()) { | |
| self._scanningState = scanningState | |
| self.onBarcodeScanned = onBarcodeScanned | |
| } | |
| func barcodeScanningDidFail() { | |
| print("Failed to scan barcode.") | |
| } | |
| func barcodeScanningDidStop() { | |
| print("Stopped scanning barcode.") | |
| } | |
| func barcodeScanningSucceededWithCode(_ barcode: String) { | |
| onBarcodeScanned(barcode) | |
| } | |
| func cameraLoaded() { | |
| withAnimation { | |
| scanningState = .cameraLoaded | |
| } | |
| } | |
| func cameraUnloaded() { | |
| withAnimation { | |
| scanningState = .cameraLoading | |
| } | |
| } | |
| } | |
| func makeCoordinator() -> BarcodeScannerViewRepresentable.Coordinator { | |
| return Coordinator(scanningState: $scanningState, | |
| onBarcodeScanned: onBarcodeScanned) | |
| } | |
| func makeUIView(context: UIViewRepresentableContext<BarcodeScannerViewRepresentable>) -> BarcodeScannerUIView { | |
| let view = BarcodeScannerUIView(frame: .zero) | |
| view.delegate = context.coordinator | |
| view.backgroundColor = .clear | |
| return view | |
| } | |
| func updateUIView(_ uiView: BarcodeScannerUIView, context: UIViewRepresentableContext<BarcodeScannerViewRepresentable>) { | |
| uiView.updateCamera(with: currentPosition) | |
| uiView.backgroundColor = .clear | |
| } | |
| } | |
| protocol BarcodeScannerUIViewDelegate: class { | |
| func barcodeScanningDidFail() | |
| func barcodeScanningSucceededWithCode(_ barcode: String) | |
| func barcodeScanningDidStop() | |
| func cameraLoaded() | |
| func cameraUnloaded() | |
| } | |
| /// BarcodeScannerUIView - adapted from https://gist.github.com/abhimuralidharan/765ecaf95cbae67de81236b0786bf59f | |
| class BarcodeScannerUIView: UIView { | |
| weak var delegate: BarcodeScannerUIViewDelegate? | |
| private let cameraLoadingDelay: Double = 0.5 // The delay for the AVCaptureVideoPreviewLayer to load. | |
| /// capture settion which allows us to start and stop scanning. | |
| var captureSession: AVCaptureSession? | |
| // Init methods.. | |
| required init?(coder aDecoder: NSCoder) { | |
| super.init(coder: aDecoder) | |
| doInitialSetup() | |
| } | |
| override init(frame: CGRect) { | |
| super.init(frame: frame) | |
| doInitialSetup() | |
| } | |
| //MARK: overriding the layerClass to return `AVCaptureVideoPreviewLayer`. | |
| override class var layerClass: AnyClass { | |
| return AVCaptureVideoPreviewLayer.self | |
| } | |
| override var layer: AVCaptureVideoPreviewLayer { | |
| return super.layer as! AVCaptureVideoPreviewLayer | |
| } | |
| var isRunning: Bool { | |
| return captureSession?.isRunning ?? false | |
| } | |
| func startScanning() { | |
| captureSession?.startRunning() | |
| } | |
| func stopScanning() { | |
| DispatchQueue.global().async { | |
| self.captureSession?.stopRunning() | |
| self.captureSession = nil | |
| self.layer.session = nil | |
| DispatchQueue.main.async { | |
| self.delegate?.barcodeScanningDidStop() | |
| } | |
| } | |
| } | |
| func updateCamera(with position: AVCaptureDevice.Position) { | |
| func cameraWithPosition(position: AVCaptureDevice.Position) -> AVCaptureDevice? { | |
| let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: position) | |
| return discoverySession.devices.first { $0.position == position } | |
| } | |
| guard let captureSession = captureSession else { | |
| return | |
| } | |
| guard let currentCameraInput = captureSession.inputs.first as? AVCaptureDeviceInput else { | |
| return | |
| } | |
| guard currentCameraInput.device.position != position else { | |
| return | |
| } | |
| captureSession.beginConfiguration() | |
| captureSession.removeInput(currentCameraInput) | |
| guard let newCamera = cameraWithPosition(position: position) else { | |
| return | |
| } | |
| do { | |
| let newVideoInput = try AVCaptureDeviceInput(device: newCamera) | |
| captureSession.addInput(newVideoInput) | |
| captureSession.commitConfiguration() | |
| } catch { | |
| // Handle this error | |
| } | |
| } | |
| /// Does the initial setup for captureSession | |
| private func doInitialSetup() { | |
| self.clipsToBounds = true | |
| DispatchQueue.global().async { | |
| let captureSession = AVCaptureSession() | |
| captureSession.startRunning() | |
| guard let videoCaptureDevice = AVCaptureDevice.default(for: .video) else { return } | |
| let videoInput: AVCaptureDeviceInput | |
| do { | |
| videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice) | |
| } catch let error { | |
| print(error) | |
| return | |
| } | |
| if captureSession.canAddInput(videoInput) { | |
| captureSession.addInput(videoInput) | |
| } else { | |
| self.scanningDidFail() | |
| return | |
| } | |
| let metadataOutput = AVCaptureMetadataOutput() | |
| if captureSession.canAddOutput(metadataOutput) { | |
| captureSession.addOutput(metadataOutput) | |
| metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main) | |
| metadataOutput.metadataObjectTypes = [.ean8, .ean13, .pdf417] | |
| } else { | |
| self.scanningDidFail() | |
| return | |
| } | |
| self.captureSession = captureSession | |
| DispatchQueue.main.asyncAfter(deadline: .now() + 0.25) { | |
| self.layer.opacity = 0 | |
| self.layer.session = self.captureSession | |
| self.layer.videoGravity = .resizeAspectFill | |
| UIView.animate(withDuration: self.cameraLoadingDelay) { | |
| self.layer.opacity = 1 | |
| self.delegate?.cameraLoaded() | |
| } | |
| } | |
| } | |
| self.layer.backgroundColor = UIColor.clear.cgColor | |
| backgroundColor = .clear | |
| } | |
| func scanningDidFail() { | |
| delegate?.barcodeScanningDidFail() | |
| captureSession = nil | |
| } | |
| func found(code: String) { | |
| delegate?.barcodeScanningSucceededWithCode(code) | |
| } | |
| } | |
| extension BarcodeScannerUIView: AVCaptureMetadataOutputObjectsDelegate { | |
| func metadataOutput(_ output: AVCaptureMetadataOutput, | |
| didOutput metadataObjects: [AVMetadataObject], | |
| from connection: AVCaptureConnection) { | |
| guard let metadataObject = metadataObjects.first, | |
| let readableObject = metadataObject as? AVMetadataMachineReadableCodeObject, | |
| let stringValue = readableObject.stringValue else { return } | |
| found(code: stringValue) | |
| } | |
| } |
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