public override void ViewDidLoad ()
{
base.ViewDidLoad ();
// Disable UI. The UI is enabled if and only if the session starts running.
MetadataObjectTypesButton.Enabled = false;
SessionPresetsButton.Enabled = false;
CameraButton.Enabled = false;
ZoomSlider.Enabled = false;
// Add the open barcode gesture recognizer to the region of interest view.
PreviewView.AddGestureRecognizer (OpenBarcodeURLGestureRecognizer);
// Set up the video preview view.
PreviewView.Session = session;
// Check video authorization status. Video access is required and audio
// access is optional. If audio access is denied, audio is not recorded
// during movie recording.
switch (AVCaptureDevice.GetAuthorizationStatus (AVMediaType.Video)) {
case AVAuthorizationStatus.Authorized:
// The user has previously granted access to the camera.
break;
case AVAuthorizationStatus.NotDetermined:
// The user has not yet been presented with the option to grant
// video access. We suspend the session queue to delay session
// setup until the access request has completed.
sessionQueue.Suspend ();
AVCaptureDevice.RequestAccessForMediaType (AVMediaType.Video, granted => {
if (!granted)
setupResult = SessionSetupResult.NotAuthorized;
sessionQueue.Resume ();
});
break;
default:
// The user has previously denied access.
setupResult = SessionSetupResult.NotAuthorized;
break;
}
// Setup the capture session.
// In general it is not safe to mutate an AVCaptureSession or any of its
// inputs, outputs, or connections from multiple threads at the same time.
// Why not do all of this on the main queue?
// Because AVCaptureSession.StartRunning() is a blocking call which can
// take a long time. We dispatch session setup to the sessionQueue so
// that the main queue isn't blocked, which keeps the UI responsive.
sessionQueue.DispatchAsync (ConfigureSession);
}
