AVFoundation Camera failing after NavigationLink swift/swiftui - ios

Question

Hi I have code for writing to the camera in Swift and SwiftUI. I'm making use of the following resource for the camera and integrated with my SwiftUI view. https://betterprogramming.pub/effortless-swiftui-camera-d7a74abde37e
For some reason, when I go to a new view after I capture a photo, and then I go back to the camera with present.wrappedValue.dismiss(), this following piece of code gets triggered from CameraService.swift:
let videoDeviceInput = try AVCaptureDeviceInput(device: videoDevice)
if session.canAddInput(videoDeviceInput) {
session.addInput(videoDeviceInput)
self.videoDeviceInput = videoDeviceInput
} else {
print("Couldn't add video device input to the session.")
setupResult = .configurationFailed
session.commitConfiguration()
return
}
and it outputs that Couldn't add video device input to the session.
Please let me know what could be this issue because it seems to be that Navigation Link is the problem as I can go around from another view to the camera view and it works fine. However, if I dismiss from my navigated view using navigation link, the code for the camera breaks.
Minimal reproducible example by modifying CameraView.swift code from the above link, as well as the GitHub repo to the link:
https://github.com/rorodriguez116/SwiftCamera
import SwiftUI
import Combine
import AVFoundation
final class CameraModel: ObservableObject {
private let service = CameraService()
#Published var photo: Photo!
#Published var showAlertError = false
#Published var isFlashOn = false
#Published var willCapturePhoto = false
var alertError: AlertError!
var session: AVCaptureSession
private var subscriptions = Set<AnyCancellable>()
init() {
self.session = service.session
service.$photo.sink { [weak self] (photo) in
guard let pic = photo else { return }
self?.photo = pic
}
.store(in: &self.subscriptions)
service.$shouldShowAlertView.sink { [weak self] (val) in
self?.alertError = self?.service.alertError
self?.showAlertError = val
}
.store(in: &self.subscriptions)
service.$flashMode.sink { [weak self] (mode) in
self?.isFlashOn = mode == .on
}
.store(in: &self.subscriptions)
service.$willCapturePhoto.sink { [weak self] (val) in
self?.willCapturePhoto = val
}
.store(in: &self.subscriptions)
}
func configure() {
service.checkForPermissions()
service.configure()
}
func capturePhoto() {
service.capturePhoto()
}
func flipCamera() {
service.changeCamera()
}
func zoom(with factor: CGFloat) {
service.set(zoom: factor)
}
func switchFlash() {
service.flashMode = service.flashMode == .on ? .off : .on
}
}
struct CameraView: View {
#StateObject var model = CameraModel()
#State var currentZoomFactor: CGFloat = 1.0
#State var showNewPost: Bool = false
var captureButton: some View {
Button(action: {
model.capturePhoto()
}, label: {
Circle()
.foregroundColor(.white)
.frame(width: 80, height: 80, alignment: .center)
.overlay(
Circle()
.stroke(Color.black.opacity(0.8), lineWidth: 2)
.frame(width: 65, height: 65, alignment: .center)
)
})
}
var capturedPhotoThumbnail: some View {
Group {
if model.photo != nil {
Image(uiImage: model.photo.image!)
.resizable()
.aspectRatio(contentMode: .fill)
.frame(width: 60, height: 60)
.clipShape(RoundedRectangle(cornerRadius: 10, style: .continuous))
.animation(.spring())
.onAppear{
self.showNewPost.toggle()
print("show new post is \(self.showNewPost)")
}
} else {
RoundedRectangle(cornerRadius: 10)
.frame(width: 60, height: 60, alignment: .center)
.foregroundColor(.black)
}
}
}
var flipCameraButton: some View {
Button(action: {
model.flipCamera()
}, label: {
Circle()
.foregroundColor(Color.gray.opacity(0.2))
.frame(width: 45, height: 45, alignment: .center)
.overlay(
Image(systemName: "camera.rotate.fill")
.foregroundColor(.white))
})
}
var body: some View {
GeometryReader { reader in
NavigationView {
ZStack {
Color.black.edgesIgnoringSafeArea(.all)
VStack {
Button(action: {
model.switchFlash()
}, label: {
Image(systemName: model.isFlashOn ? "bolt.fill" : "bolt.slash.fill")
.font(.system(size: 20, weight: .medium, design: .default))
})
.accentColor(model.isFlashOn ? .yellow : .white)
CameraPreview(session: model.session)
.gesture(
DragGesture().onChanged({ (val) in
// Only accept vertical drag
if abs(val.translation.height) > abs(val.translation.width) {
// Get the percentage of vertical screen space covered by drag
let percentage: CGFloat = -(val.translation.height / reader.size.height)
// Calculate new zoom factor
let calc = currentZoomFactor + percentage
// Limit zoom factor to a maximum of 5x and a minimum of 1x
let zoomFactor: CGFloat = min(max(calc, 1), 5)
// Store the newly calculated zoom factor
currentZoomFactor = zoomFactor
// Sets the zoom factor to the capture device session
model.zoom(with: zoomFactor)
}
})
)
.onAppear {
model.configure()
}
.alert(isPresented: $model.showAlertError, content: {
Alert(title: Text(model.alertError.title), message: Text(model.alertError.message), dismissButton: .default(Text(model.alertError.primaryButtonTitle), action: {
model.alertError.primaryAction?()
}))
})
.overlay(
Group {
if model.willCapturePhoto {
Color.black
}
}
)
.animation(.easeInOut)
HStack {
capturedPhotoThumbnail
Spacer()
captureButton
Spacer()
flipCameraButton
}
.padding(.horizontal, 20)
}
NavigationLink(destination: NewPost(), isActive: $showNewPost) {
}
}
}
}
}
}
struct NewPost: View {
#Environment(\.presentationMode) var present
var body: some View {
Button(action: {
print("tapped button")
present.wrappedValue.dismiss() //triggers the configuration failed
}, label: {
Text("new post").foregroundColor(Color.black)
})
}
}