Button that starts/stops a screen recording and present the user with the Apple-provided preview

ContentView.swift

// How to use it:

import SwiftUI

struct ContentView: View {
    var body: some View {
        RecordScreenButton()
    }
}

RecordScreenButton.swift

//
//  RecordScreenButton.swift
//
//
//  Created by Mathijs Bernson on 26/01/2023.
//  Copyright © 2023 Q42. All rights reserved.
//

import SwiftUI
import ReplayKit
import os.log

struct RecordScreenButton: View {
    @StateObject private var model = ScreenRecorderModel()

    var body: some View {
        Button {
#if targetEnvironment(simulator)
            model.showError(title: "Screen recording is not supported in the simulator", underlyingError: nil)
#else
            if model.isRecording {
                model.stopRecording()
            } else {
                model.startRecording()
            }
#endif
        } label: {
            Image(systemName: model.isRecording ? "stop.circle" : "record.circle")
                .foregroundColor(model.isRecording ? .red : .primary)
                .animation(.easeOut, value: model.isRecording)
        }
        .accessibilityLabel("Record screen")
        .disabled(!model.screenRecorder.isAvailable)
        .sheet(isPresented: $model.isPresentingPreview) {
            ScreenRecorderPreview(previewController: model.previewController!)
                .ignoresSafeArea(.container, edges: .bottom)
        }
        .alert(isPresented: $model.isPresentingError, error: model.error) { error in
            Button("Ok") {}
        } message: { error in
            if let failureReason = error.failureReason {
                Text(failureReason)
            }
        }
    }
}

private struct ScreenRecorderPreview: UIViewControllerRepresentable {
    let previewController: RPPreviewViewController

    func makeUIViewController(context: Context) -> RPPreviewViewController {
        previewController
    }

    func updateUIViewController(_ viewController: RPPreviewViewController, context: Context) {}
}

private struct ScreenRecorderError: LocalizedError {
    let errorDescription: String?
    let failureReason: String?

    init(title: String, underlyingError: Error?) {
        self.errorDescription = title
        self.failureReason = underlyingError?.localizedDescription
    }
}

private class ScreenRecorderModel: NSObject, ObservableObject {
    let screenRecorder = RPScreenRecorder.shared()
    let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "ScreenRecorder")

    @Published var isRecording: Bool = false

    @Published var isPresentingPreview: Bool = false
    var previewController: RPPreviewViewController?

    @Published var isPresentingError: Bool = false
    @Published var error: ScreenRecorderError?

    override init() {
        isRecording = RPScreenRecorder.shared().isRecording
        super.init()
        screenRecorder.isMicrophoneEnabled = false
        screenRecorder.isCameraEnabled = false
    }

    func startRecording() {
        isRecording = true
        screenRecorder.startRecording { error in
            if let error {
                self.logger.error("Unable to start screen recording: \(error.localizedDescription)")
                self.isRecording = false
                self.showError(title: String(localized: "Unable to start screen recording"), underlyingError: error)
            } else {
                self.logger.info("Screen recorder started.")
            }
        }
    }

    func stopRecording() {
        screenRecorder.stopRecording { previewController, error in
            self.isRecording = false
            if let error {
                self.logger.error("Screen recording failed: \(error.localizedDescription)")
                self.showError(title: String(localized: "Screen recording failed"), underlyingError: error)
            } else if let previewController {
                self.logger.info("Screen recorder finished. Showing preview to user.")
                previewController.previewControllerDelegate = self
                self.isPresentingPreview = true
                self.previewController = previewController
            }
        }
    }

    func showError(title: String, underlyingError error: Error?) {
        self.isPresentingError = true
        self.error = .init(title: title, underlyingError: error)
    }
}

extension ScreenRecorderModel: RPPreviewViewControllerDelegate {
    func previewControllerDidFinish(_ previewController: RPPreviewViewController) {
        dismissPreview()
    }

    func dismissPreview() {
        isPresentingPreview = false
        previewController = nil
    }
}