相关疑难解决方法(0)

无法想象这一个.当应用程序处于活动状态时,一切正常,有时当我将应用程序移动到后台(按下主页按钮)而不是返回时,预览层会冻结/卡住.我使用viewWillAppear和viewDidAppear进行设置.这是我如何设置一切:

  var backCamera = AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo)
  var global_device : AVCaptureDevice!
  var captureSession: AVCaptureSession?

override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)

captureSession = AVCaptureSession()
        captureSession!.sessionPreset = AVCaptureSessionPresetPhoto
        CorrectPosition = AVCaptureDevicePosition.Back
        for device in backCamera {
            if device.position == AVCaptureDevicePosition.Back {
                global_device = device as! AVCaptureDevice
                CorrectPosition = AVCaptureDevicePosition.Back
                break
            }
        }


        configureCamera()
        var error: NSError?
        var input = AVCaptureDeviceInput(device: global_device, error: &error)


        if error == nil && captureSession!.canAddInput(input) {
            captureSession!.addInput(input)

            stillImageOutput = AVCaptureStillImageOutput()
            stillImageOutput!.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
            if captureSession!.canAddOutput(stillImageOutput) {
                captureSession!.addOutput(stillImageOutput) …