SwiftのSwiftUI App形式で「SceneDelegate」とかを使ったカメラアプリ作成ログ

機械学習のcoreML用にswiftを使ったカメラアプリを作ってみた。その時、

・従来のAppKitApp Delegate形式
から
・新しい記述形式のSwiftUI App形式

を主にした
・SceneDelegate.swift
・AppDelegate.swift
を使ったカメラアプリの作成して使う方法を簡単にまとめる

目次
1.ファイル構成
2.Info.plistの設定
3.ファイル一覧

1.ファイル構成

メインのファイル構成

$ tree ResNet50prj
├── Interactor.swift
├── CameraController.swift
├── CameraViewController.swift
├── ContentView.swift
├── Info.plist
├── AppDelegate.swift
└── SceneDelegate.swift

Info.plistの設定

・カメラのアクセス許可
・SceneDelegateとAppDeletegateを使った形式でアプリを使うためにApplication Scene Manifestを追加

以下のように設定

ファイル一覧

AppDelegate.swift

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        return true
    }

    // MARK: UISceneSession Lifecycle
    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }
}

SceneDelegate.swift

import UIKit
import SwiftUI

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
        // Create the SwiftUI view that provides the window contents.
        let contentView = ContentView()

        // Use a UIHostingController as window root view controller.
        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        }
    }

    func sceneDidDisconnect(_ scene: UIScene) {
        // Called as the scene is being released by the system.
        // This occurs shortly after the scene enters the background, or when its session is discarded.
        // Release any resources associated with this scene that can be re-created the next time the scene connects.
        // The scene may re-connect later, as its session was not neccessarily discarded (see `application:didDiscardSceneSessions` instead).
    }

    func sceneDidBecomeActive(_ scene: UIScene) {
        // Called when the scene has moved from an inactive state to an active state.
        // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive.
    }

    func sceneWillResignActive(_ scene: UIScene) {
        // Called when the scene will move from an active state to an inactive state.
        // This may occur due to temporary interruptions (ex. an incoming phone call).
    }

    func sceneWillEnterForeground(_ scene: UIScene) {
        // Called as the scene transitions from the background to the foreground.
        // Use this method to undo the changes made on entering the background.
    }

    func sceneDidEnterBackground(_ scene: UIScene) {
        // Called as the scene transitions from the foreground to the background.
        // Use this method to save data, release shared resources, and store enough scene-specific state information
        // to restore the scene back to its current state.
    }
}

ContentView.swift

import SwiftUI
struct ContentView: View {
    var body: some View {
        CameraViewController()
            .edgesIgnoringSafeArea(.top)
    }
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Interactor.swift

import Foundation
import AVKit

final class SimpleVideoCaptureInteractor: NSObject, ObservableObject {
    private let captureSession = AVCaptureSession()
    @Published var previewLayer: AVCaptureVideoPreviewLayer?
    private var captureDevice: AVCaptureDevice?

    /// - Tag: CreateCaptureSession
     func setupAVCaptureSession() {
         print(#function)
         captureSession.sessionPreset = .photo
         if let availableDevice = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: .video, position: .back).devices.first {
             captureDevice = availableDevice
         }

         do {
             let captureDeviceInput = try AVCaptureDeviceInput(device: captureDevice!)
             captureSession.addInput(captureDeviceInput)
         } catch let error {
             print(error.localizedDescription)
         }

         let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        previewLayer.name = "CameraPreview"
        previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
        previewLayer.backgroundColor = UIColor.black.cgColor
         self.previewLayer = previewLayer

         let dataOutput = AVCaptureVideoDataOutput()
         dataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as String:kCVPixelFormatType_32BGRA]

         if captureSession.canAddOutput(dataOutput) {
             captureSession.addOutput(dataOutput)
         }
         captureSession.commitConfiguration()
     }

    func startSettion() {
        if captureSession.isRunning { return }
        captureSession.startRunning()
    }

    func stopSettion() {
        if !captureSession.isRunning { return }
        captureSession.stopRunning()
    }
}

CameraController.swift

import UIKit
import AVFoundation

class CameraController: NSObject{
    var captureSession: AVCaptureSession?
    var backCamera: AVCaptureDevice?
    var backCameraInput: AVCaptureDeviceInput?
    var previewLayer: AVCaptureVideoPreviewLayer?
    
    enum CameraControllerError: Swift.Error {
        case captureSessionAlreadyRunning
        case captureSessionIsMissing
        case inputsAreInvalid
        case invalidOperation
        case noCamerasAvailable
        case unknown
    }
    
    func prepare(completionHandler: @escaping (Error?) -> Void){
        func createCaptureSession(){
            self.captureSession = AVCaptureSession()
        }
        func configureCaptureDevices() throws {
            let camera = AVCaptureDevice.default(.builtInWideAngleCamera, for: AVMediaType.video, position: .back)
            
            self.backCamera = camera
            
            try camera?.lockForConfiguration()
            camera?.unlockForConfiguration()
            
        }
        func configureDeviceInputs() throws {
            guard let captureSession = self.captureSession else { throw CameraControllerError.captureSessionIsMissing }
            
            if let backCamera = self.backCamera {
                self.backCameraInput = try AVCaptureDeviceInput(device: backCamera)
                
                if captureSession.canAddInput(self.backCameraInput!) { captureSession.addInput(self.backCameraInput!)}
                else { throw CameraControllerError.inputsAreInvalid }
                
            }
            else { throw CameraControllerError.noCamerasAvailable }
            
            captureSession.startRunning()
            
        }
        
        DispatchQueue(label: "prepare").async {
            do {
                createCaptureSession()
                try configureCaptureDevices()
                try configureDeviceInputs()
            }
                
            catch {
                DispatchQueue.main.async{
                    completionHandler(error)
                }
                
                return
            }
            
            DispatchQueue.main.async {
                completionHandler(nil)
            }
        }
    }
    func displayPreview(on view: UIView) throws {
        guard let captureSession = self.captureSession, captureSession.isRunning else { throw CameraControllerError.captureSessionIsMissing }
        
        self.previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        self.previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
        self.previewLayer?.connection?.videoOrientation = .portrait
        
        view.layer.insertSublayer(self.previewLayer!, at: 0)
        self.previewLayer?.frame = view.frame
    }   
}

CameraViewController.swift

import UIKit
import SwiftUI

final class CameraViewController: UIViewController {
    let cameraController = CameraController()
    var previewView: UIView!
    
    override func viewDidLoad() {
                
        previewView = UIView(frame: CGRect(x:0, y:0, width: UIScreen.main.bounds.size.width, height: UIScreen.main.bounds.size.height))
        previewView.contentMode = UIView.ContentMode.scaleAspectFit
        view.addSubview(previewView)
        
        cameraController.prepare {(error) in
            if let error = error {
                print(error)
            }
            
            try? self.cameraController.displayPreview(on: self.previewView)
        }
        
    }
}

extension CameraViewController : UIViewControllerRepresentable{
    public typealias UIViewControllerType = CameraViewController
    
    public func makeUIViewController(context: UIViewControllerRepresentableContext<CameraViewController>) -> CameraViewController {
        return CameraViewController()
    }
    
    public func updateUIViewController(_ uiViewController: CameraViewController, context: UIViewControllerRepresentableContext<CameraViewController>) {
    }
}

参考サイト

・SwiftUI-Simple-camera-app
・今までStoryboardしか使っていないプロジェクトで、SwiftUIをとりあえず表示させるまで。