我有一个带有 SwiftUI 生命周期的简单 SwiftUI 应用程序，我正在尝试使用 AVFoundation 自动拍照。我会根据条件或 基于计时器 - 但对于这个例子，我只想在启动时拍照 并显示它(不是预览层)。我不希望需要任何用户操作。
我显然不了解正确的设置和捕获。
import SwiftUI
import AVFoundation
struct ContentView: View {
let dataStore = DataStore.shared
@State private var captureSession = AVCaptureSession()
@State private var backCamera : AVCaptureDevice?
@State private var frontCamera : AVCaptureDevice?
@State private var currentCamera : AVCaptureDevice?
@State private var photoOutput : AVCapturePhotoOutput?
@State private var capturedImage: UIImage?
var body: some View {
VStack {
Text("Take a Photo Automatically")
.padding()
ZStack {
RoundedRectangle(cornerRadius: 0)
.stroke(Color.blue, lineWidth: 4)
.frame(width: 320, height: 240, alignment: .center)
Image(uiImage: dataStore.capturedImage)
}
Spacer()
}
.onAppear {
if UIImagePickerController.isSourceTypeAvailable(.camera){
self.setupCaptureSession()
self.setupDevices()
self.setupInputOutput()
self.startRunningCaptureSession()
} else {
print("No Camera is Available")
}
}
}
func setupCaptureSession() {
captureSession.sessionPreset = AVCaptureSession.Preset.photo
}//setupCaptureSession
func setupDevices() {
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [AVCaptureDevice.DeviceType.builtInWideAngleCamera], mediaType: .video, position: .unspecified)
let devices = deviceDiscoverySession.devices
for device in devices {
if device.position == AVCaptureDevice.Position.back {
backCamera = device
} else if device.position == AVCaptureDevice.Position.front {
frontCamera = device
}//if else
}//for in
currentCamera = frontCamera
}//setupDevices
func setupInputOutput() {
do {
//you only get here if there is a camera ( ! ok )
let captureDeviceInput = try AVCaptureDeviceInput(device: currentCamera!)
captureSession.addInput(captureDeviceInput)
photoOutput = AVCapturePhotoOutput()
photoOutput?.setPreparedPhotoSettingsArray([AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])], completionHandler: {(success, error) in
})
captureSession.addOutput(photoOutput!)
captureSession.commitConfiguration()
} catch {
print("Error creating AVCaptureDeviceInput:", error)
}
}//setupInputOutput
func startRunningCaptureSession() {
let settings = AVCapturePhotoSettings()
captureSession.startRunning()
photoOutput?.capturePhoto(with: settings, delegate: PhotoDelegate())
}//startRunningCaptureSession
}//struct
class PhotoDelegate: NSObject, AVCapturePhotoCaptureDelegate {
let dataStore = DataStore.shared
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
guard let data = photo.fileDataRepresentation(),
let image = UIImage(data: data) else {
return
}
dataStore.capturedImage = image
}
}//photo delegate
class DataStore {
static let shared = DataStore()
private init() {}
@Published var capturedImage: UIImage = UIImage()
}//dataStore
任何指导将不胜感激。 Xcode 12.5.1 iOS 14.5
第二次尝试添加示例:
稍后编辑。在使用 Philip Dukhov 提供的更改纠正我的方法后， 我仍然有一个问题 - 图像仍然很暗 - 以至于物体都 面目全非。试了很多次，看来相机需要一些 捕获前的设置时间非常短。虽然它看起来不像 好的编程计划，我在 session 捕获之前设置了一个轻微的延迟。作为 仅仅 0.1 秒似乎就足够了。现在开始捕获:
func startRunningCaptureSession() {
let settings = AVCapturePhotoSettings()
captureSession.startRunning()
//don't know why this is needed - but it works. Low number of tests at 0.1 all work
DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
self.photoOutput?.capturePhoto(with: settings, delegate: self)
}
}//start Running Capture Session
如果您知道更好的方法 - 请告诉我。
最佳答案
主要问题是您创建了一个 PhotoDelegate 但没有存储它。在 iOS 中，delegate 对象通常存储为弱引用，以防止循环引用/保留循环。
您只需在 View 中创建另一个属性即可解决此问题，但我建议您创建一个模型类。如果您正在做一些与 View 本身无关的事情，这表明您最好将它移到其他地方，例如 ObservableObject。您还可以将其作为您的委托(delegate)，这样您就不必创建单独的对象并使用单例:这是您做错事情的另一个迹象。
class CaptureModel: NSObject, ObservableObject {
let captureSession = AVCaptureSession()
var backCamera: AVCaptureDevice?
var frontCamera: AVCaptureDevice?
var photoOutput: AVCapturePhotoOutput?
var currentCamera: AVCaptureDevice?
@Published
var capturedImage: UIImage?
override init() {
super.init()
setupCaptureSession()
setupDevices()
setupInputOutput()
}
func setupCaptureSession() {
captureSession.sessionPreset = AVCaptureSession.Preset.photo
}//setupCaptureSession
func setupDevices() {
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [AVCaptureDevice.DeviceType.builtInWideAngleCamera], mediaType: .video, position: .unspecified)
let devices = deviceDiscoverySession.devices
for device in devices {
if device.position == AVCaptureDevice.Position.back {
backCamera = device
} else if device.position == AVCaptureDevice.Position.front {
frontCamera = device
}//if else
}//for in
currentCamera = frontCamera
}//setupDevices
func setupInputOutput() {
do {
//you only get here if there is a camera ( ! ok )
let captureDeviceInput = try AVCaptureDeviceInput(device: currentCamera!)
captureSession.addInput(captureDeviceInput)
photoOutput = AVCapturePhotoOutput()
photoOutput?.setPreparedPhotoSettingsArray([AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])], completionHandler: {(success, error) in
})
captureSession.addOutput(photoOutput!)
captureSession.commitConfiguration()
} catch {
print("Error creating AVCaptureDeviceInput:", error)
}
}//setupInputOutput
func startRunningCaptureSession() {
let settings = AVCapturePhotoSettings()
captureSession.startRunning()
photoOutput?.capturePhoto(with: settings, delegate: self)
}//startRunningCaptureSession
func stopRunningCaptureSession() {
captureSession.stopRunning()
}//startRunningCaptureSession
}
extension CaptureModel: AVCapturePhotoCaptureDelegate {
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
guard let data = photo.fileDataRepresentation(),
let image = UIImage(data: data) else {
return
}
capturedImage = image
}
}
struct ContentView: View {
@StateObject
var model = CaptureModel()
var body: some View {
VStack {
Text("Take a Photo Automatically")
.padding()
ZStack {
RoundedRectangle(cornerRadius: 0)
.stroke(Color.blue, lineWidth: 4)
.frame(width: 320, height: 240, alignment: .center)
model.capturedImage.map { capturedImage in
Image(uiImage: capturedImage)
}
}
Spacer()
}
.onAppear {
if UIImagePickerController.isSourceTypeAvailable(.camera) {
model.startRunningCaptureSession()
} else {
print("No Camera is Available")
}
}
.onDisappear {
model.stopRunningCaptureSession()
}
}
}//struct
关于ios - SwiftUI AVCapturePhotoOutput 不工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/69058038/