public ActivityDatum(DateTimeOffset timestamp, Activities activity, ActivityPhase phase, ActivityState state, ActivityConfidence confidence)
: base(timestamp)
{
Activity = activity;
Phase = phase;
State = state;
Confidence = confidence;
}
protected override async Task <List <Datum> > PollAsync(CancellationToken cancellationToken)
{
List <Datum> data = new List <Datum>();
// if this is the first poll (no existing query start time), set the query start time to the current time. we
// used to set this to the maximally previous time per ios documentation (7 days), but this (1) causes issues
// when triggering surveys on the basis of these activities (there might be hundreds of activities within the
// past 7 days), and it also runs counter to the user's expectations that data will only be collected from the
// time at which they have enrolled in the study and not from times prior.
if (_queryStartTime == null)
{
_queryStartTime = DateTimeOffset.UtcNow;
}
await SensusContext.Current.MainThreadSynchronizer.ExecuteThreadSafe(async() =>
{
try
{
CMMotionActivityManager activityManager = new CMMotionActivityManager();
CMMotionActivity[] activities = await activityManager.QueryActivityAsync(_queryStartTime.Value.UtcDateTime.ToNSDate(), NSDate.Now, NSOperationQueue.CurrentQueue);
// process each activity, keeping track of most recent
NSDate mostRecentActivityStartTime = null;
foreach (CMMotionActivity activity in activities)
{
DateTimeOffset timestamp = new DateTimeOffset(activity.StartDate.ToDateTime(), TimeSpan.Zero);
#region get confidence
ActivityConfidence confidence = ActivityConfidence.NotAvailable;
if (activity.Confidence == CMMotionActivityConfidence.Low)
{
confidence = ActivityConfidence.Low;
}
else if (activity.Confidence == CMMotionActivityConfidence.Medium)
{
confidence = ActivityConfidence.Medium;
}
else if (activity.Confidence == CMMotionActivityConfidence.High)
{
confidence = ActivityConfidence.High;
}
else
{
SensusException.Report("Unrecognized confidence: " + activity.Confidence);
}
#endregion
#region get activities
Action <Activities> AddActivityDatum = activityType =>
{
ActivityDatum activityDatum = new ActivityDatum(timestamp, activityType, ActivityPhase.Starting, ActivityState.Active, confidence);
data.Add(activityDatum);
};
if (activity.Stationary)
{
AddActivityDatum(Activities.Still);
}
if (activity.Walking)
{
AddActivityDatum(Activities.Walking);
}
if (activity.Running)
{
AddActivityDatum(Activities.Running);
}
if (activity.Automotive)
{
AddActivityDatum(Activities.InVehicle);
}
if (activity.Cycling)
{
AddActivityDatum(Activities.OnBicycle);
}
if (activity.Unknown)
{
AddActivityDatum(Activities.Unknown);
}
#endregion
if (mostRecentActivityStartTime == null)
{
mostRecentActivityStartTime = activity.StartDate;
}
else
{
mostRecentActivityStartTime = mostRecentActivityStartTime.LaterDate(activity.StartDate);
}
}
// set the next query start time one second after the most recent activity's start time
if (mostRecentActivityStartTime != null)
{
_queryStartTime = new DateTime(mostRecentActivityStartTime.ToDateTime().Ticks, DateTimeKind.Utc).AddSeconds(1);
}
}
catch (Exception ex)
{
SensusServiceHelper.Get().Logger.Log("Exception while querying activities: " + ex, LoggingLevel.Normal, GetType());
}
});
// let the system know that we polled but didn't get any data
if (data.Count == 0)
{
data.Add(null);
}
return(data);
}
