private void AddObservers()
{
_runningObserver = _session.AddObserver("running", NSKeyValueObservingOptions.New, OnSessionRunningChangedHandler);
if (_stillImageOutput != null)
{
_capturingStillObserver = _stillImageOutput.AddObserver("capturingStillImage", NSKeyValueObservingOptions.New, OnCapturingStillImageChangedHandler);
}
_recordingObserver = _movieFileOutput.AddObserver("recording", NSKeyValueObservingOptions.New, OnRecordingChangedHandler);
_subjectSubscriber = NSNotificationCenter.DefaultCenter.AddObserver(AVCaptureDevice.SubjectAreaDidChangeNotification, OnSubjectAreaChangedHandler, _videoDeviceInput.Device);
_runtimeErrorObserver = NSNotificationCenter.DefaultCenter.AddObserver(AVCaptureSession.RuntimeErrorNotification, OnSessionRuntimeErrorOccuredHandler, _session);
// A session can only run when the app is full screen. It will be interrupted in a multi-app layout, introduced in iOS 9.
// Add observers to handle these session interruptions
// and show a preview is paused message. See the documentation of AVCaptureSession.WasInterruptedNotification for other
// interruption reasons.
_interuptionObserver = NSNotificationCenter.DefaultCenter.AddObserver(AVCaptureSession.WasInterruptedNotification, OnSessionWasInterruptedHandler, _session);
_interuptionEndedObserver = NSNotificationCenter.DefaultCenter.AddObserver(AVCaptureSession.InterruptionEndedNotification, OnSessionInterruptionEndedHandler, _session);
}