I am trying to use a Picker to select a VideoFormat from Twilio's Video API via a ForEach loop. The loop is working– it lists all of the correctly formatted format strings.
Here's my view, SettingsView
:
import SwiftUI
struct SettingsView: View {
@EnvironmentObject var twilioState: TwilioState
var body: some View {
Form {
Section(header: Text("Stream")) {
HStack {
Text("Device")
Spacer()
Text("\(twilioState.captureDevice?.localizedName ?? "N/A")")
}
This is where I run into trouble. I cannot seem to get the Picker
to assign a value to my selection
, $twilioState.videoFormat
. I suspect it has something to do with id
and VideoFormat
not conforming to Hashable
? I was considering changing the selection
to an Int
and using a range for ForEach
, like 0..<twilioState.videoFormats.count
.
Picker("Select a Format", selection: $twilioState.videoFormat) {
if let videoFormats = twilioState.videoFormats {
ForEach(videoFormats, id: \.self) {
Text("\(twilioState.getVideoFormatString(videoFormat: $0))")
.tag($0)
}
}
}
.disabled(twilioState.videoFormats == nil)
The rest is a listing of twilioState.videoFormat
as I try to figure out how to successfully implement the Picker
.
HStack {
Text("Format")
Spacer()
if let videoFormat = twilioState.videoFormat {
Text("\(twilioState.getVideoFormatString(videoFormat: videoFormat))")
} else {
Text("N/A")
}
}
}
}
.navigationBarTitle("Settings")
}
}
And here's my state model, TwilioState
:
import Foundation
import TwilioVideo
import Combine
class TwilioState: ObservableObject {
let twilioService = TwilioService()
private var cancellables = Set<AnyCancellable>()
var camera: CameraSource?
@Published var videoFormat: VideoFormat?
@Published var videoFormats: [VideoFormat]?
@Published var captureDevice: AVCaptureDevice?
@Published var twilioError: TwilioError?
init() {
twilioService.setCaptureDevice(captureDevice: self.captureDevice)
.sink { completion in
switch completion {
case let .failure(twilioError):
return self.twilioError = twilioError
case .finished:
return print("Capture device set")
}
} receiveValue: { captureDevice in
self.captureDevice = captureDevice
}
.store(in: &cancellables)
twilioService.getVideoFormats(captureDevice: self.captureDevice!)
.sink { completion in
switch completion {
case let .failure(twilioError):
return self.twilioError = twilioError
case .finished: return print("Capture device formats set")
}
} receiveValue: { videoFormats in
self.videoFormats = videoFormats
}
.store(in: &cancellables)
}
func getVideoFormatString(videoFormat: VideoFormat) -> String {
return "\(videoFormat.dimensions.width) x \(videoFormat.dimensions.height) @ \(videoFormat.frameRate)"
}
deinit {
// We are done with camera
if let camera = self.camera {
camera.stopCapture()
self.camera = nil
}
}
}
In case it's helpful, this is the service function, getVideoFormats()
, which is feeding values to @Published videoFormats
in my model, TwilioState
:
func getVideoFormats(captureDevice: AVCaptureDevice) -> AnyPublisher<[VideoFormat], TwilioError> {
return Just(captureDevice)
.map { captureDevice -> [VideoFormat] in
return CameraSource.supportedFormats(captureDevice: captureDevice)
.compactMap { $0 as? VideoFormat }
}
.setFailureType(to: TwilioError.self)
.eraseToAnyPublisher()
}
I solved this by casting the selection type into an optional using the tag modifier:
Picker("Select a Format", selection: $twilioState.videoFormat) {
if let videoFormats = twilioState.videoFormats {
ForEach(videoFormats, id: \.self) { videoFormat in
Text("\(twilioState.getVideoFormatString(videoFormat: videoFormat))")
.tag(videoFormat as VideoFormat?)
}
}
}
See this post for more: Picker for optional data type in SwiftUI?