Ios 如何停止collectionView单元格中的相机延迟?
我有一个collectionView,它的单元格充当屏幕。当我在打开应用程序后滑动到相机单元时,会有一秒钟的延迟,然后在之后,来回滑动是平滑的,下面是这个延迟的视频。是否有任何方法可以防止这种情况,或者在到达单元格之前在后台启动捕获会话?谢谢你的帮助 摄像机单元代码Ios 如何停止collectionView单元格中的相机延迟?,ios,swift,avfoundation,grand-central-dispatch,avcapturesession,Ios,Swift,Avfoundation,Grand Central Dispatch,Avcapturesession,我有一个collectionView,它的单元格充当屏幕。当我在打开应用程序后滑动到相机单元时,会有一秒钟的延迟,然后在之后,来回滑动是平滑的,下面是这个延迟的视频。是否有任何方法可以防止这种情况,或者在到达单元格之前在后台启动捕获会话?谢谢你的帮助 摄像机单元代码 import UIKit import AVFoundation class MainCameraCollectionViewCell: UICollectionViewCell { var captureSessi
import UIKit
import AVFoundation
class MainCameraCollectionViewCell: UICollectionViewCell {
var captureSession = AVCaptureSession()
private var sessionQueue: DispatchQueue!
var captureConnection = AVCaptureConnection()
var backCamera: AVCaptureDevice?
var frontCamera: AVCaptureDevice?
var currentCamera: AVCaptureDevice?
var photoOutPut: AVCapturePhotoOutput?
var cameraPreviewLayer: AVCaptureVideoPreviewLayer?
var image: UIImage?
var usingFrontCamera = false
override func awakeFromNib() {
super.awakeFromNib()
setupCaptureSession()
setupDevice()
setupInput()
self.setupPreviewLayer()
startRunningCaptureSession
}
func setupCaptureSession(){
captureSession.sessionPreset = AVCaptureSession.Preset.photo
sessionQueue = DispatchQueue(label: "session queue")
}
func setupDevice(usingFrontCamera:Bool = false){
DispatchQueue.main.async {
//sessionQueue.async {
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [AVCaptureDevice.DeviceType.builtInWideAngleCamera], mediaType: AVMediaType.video, position: AVCaptureDevice.Position.unspecified)
let devices = deviceDiscoverySession.devices
for device in devices{
if usingFrontCamera && device.position == AVCaptureDevice.Position.front {
//backCamera = device
self.currentCamera = device
} else if device.position == AVCaptureDevice.Position.back {
//frontCamera = device
self.currentCamera = device
}
}
}
}
func setupInput() {
DispatchQueue.main.async {
do {
let captureDeviceInput = try AVCaptureDeviceInput(device: self.currentCamera!)
if self.captureSession.canAddInput(captureDeviceInput) {
self.captureSession.addInput(captureDeviceInput)
}
self.photoOutPut = AVCapturePhotoOutput()
self.photoOutPut?.setPreparedPhotoSettingsArray([AVCapturePhotoSettings(format:[AVVideoCodecKey: AVVideoCodecType.jpeg])], completionHandler: nil)
if self.captureSession.canAddOutput(self.photoOutPut!) {
self.captureSession.addOutput(self.photoOutPut!)
}
} catch {
print(error)
}
}
}
func setupPreviewLayer(){
cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
cameraPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
cameraPreviewLayer?.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
cameraPreviewLayer?.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
self.layer.insertSublayer(cameraPreviewLayer!, at: 0)
}
func startRunningCaptureSession(){
captureSession.startRunning()
}
@IBAction func cameraButton_Touched(_ sender: Any) {
let settings = AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])
//
settings.isAutoStillImageStabilizationEnabled = true
if let photoOutputConnection = self.photoOutPut?.connection(with: .video){
photoOutputConnection.videoOrientation = (cameraPreviewLayer?.connection?.videoOrientation)!
}
}
@IBAction func Flip_camera(_ sender: UIButton?) {
print("Flip Touched")
self.captureSession.beginConfiguration()
if let inputs = self.captureSession.inputs as? [AVCaptureDeviceInput] {
for input in inputs {
self.captureSession.removeInput(input)
print("input removed")
}
//This seemed to have fixed it
for output in self.captureSession.outputs{
captureSession.removeOutput(output)
print("out put removed")
}
}
self.usingFrontCamera = !self.usingFrontCamera
self.setupCaptureSession()
self.setupDevice(usingFrontCamera: self.usingFrontCamera)
self.setupInput()
self.captureSession.commitConfiguration()
self.startRunningCaptureSession()
}
}
初始化相机需要时间。一旦你的应用程序请求使用摄像头,支持软件就必须在后台初始化,这实际上是不可能加速的
我建议将与AVFoundation相关的任何内容放在后台线程中,并在应用程序加载后初始化它。这样,一旦用户准备好刷卡到相机单元,相机就可以为用户准备好了。如果你不想预加载,你至少可以把背景放在后台,并利用某种活动指示器来显示用户正在加载东西,而不是让你的主线程在摄像机启动时被阻挡。< / P>如果我的答案是有用的,你能考虑接受吗?