private const int maxEventDescriptors = 42; // Value determined by how many max length event descriptors (91 chars)
// stored as a JSON string can fit in 8K (max allowed for local settings)
void IBackgroundTask.Run(IBackgroundTaskInstance taskInstance)
{
BackgroundTaskDeferral deferral = taskInstance.GetDeferral();
GeovisitTriggerDetails triggerDetails = (GeovisitTriggerDetails)taskInstance.TriggerDetails;
// Handle Visit reports
GetVisitReports(triggerDetails);
deferral.Complete();
}
public async void Run(IBackgroundTaskInstance taskInstance)
{
_deferral = taskInstance.GetDeferral();
GeovisitTriggerDetails visit = (GeovisitTriggerDetails)taskInstance.TriggerDetails;
var client = DigitServiceBuilder.Get();
var reports = visit.ReadReports();
var msg = string.Join("\n", reports.Select(r => $"{r.Timestamp} {r.StateChange} {r.Position.Coordinate.Point}").ToArray());
await client.LogAsync($"Geovisit:\n{msg}");
_deferral.Complete();
}
private void GetVisitReports(GeovisitTriggerDetails triggerDetails)
{
// First fill the _visitBackgroundEvents with previous existing reports saved in local settings.
_visitBackgroundEvents.Clear();
FillReportCollectionWithExistingReports();
// Read reports from the triggerDetails.
IReadOnlyList <Geovisit> reports = triggerDetails.ReadReports();
string visitItemEvent = null;
int numReports = reports.Count;
DateTimeFormatter formatterLongTime = new DateTimeFormatter("{hour.integer}:{minute.integer(2)}:{second.integer(2)}", new[] { "en-US" }, "US", CalendarIdentifiers.Gregorian, ClockIdentifiers.TwentyFourHour);
foreach (Geovisit report in reports)
{
visitItemEvent = formatterLongTime.Format(report.Timestamp);
visitItemEvent += " " + report.StateChange.ToString();
// Check if the report has a valid position.
if (report.Position != null)
{
visitItemEvent += " (" +
report.Position.Coordinate.Point.Position.Latitude.ToString() + "," +
report.Position.Coordinate.Point.Position.Longitude.ToString() +
")";
}
// Now add each new visit report to _VisitBackgroundEvents.
AddVisitReport(visitItemEvent);
}
if (numReports != 0)
{
// Save all the reports back to the local settings.
SaveExistingReports();
// NOTE: Other notification mechanisms can be used here, such as Badge and/or Tile updates.
DoToast(numReports, visitItemEvent);
}
}
private void ProcessVisitReports(GeovisitTriggerDetails triggerDetails)
{
// Load the values saved from last time.
JsonArray visitBackgroundEvents = Helpers.LoadSavedJson("BackgroundVisitEventCollection");
// Read reports from the triggerDetails.
IReadOnlyList <Geovisit> reports = triggerDetails.ReadReports();
string description = null;
foreach (Geovisit report in reports)
{
description = GenerateVisitDescription(report);
// Add to the collection, trimming old events if necessary.
if (visitBackgroundEvents.Count == maxEventDescriptors)
{
visitBackgroundEvents.RemoveAt(maxEventDescriptors - 1);
}
visitBackgroundEvents.Insert(0, JsonValue.CreateStringValue(description));
}
int numReports = reports.Count;
if (numReports > 0)
{
// Save the modified results for next time.
_values["BackgroundVisitEventCollection"] = visitBackgroundEvents.Stringify();
if (numReports > 1)
{
description = $"There are {numReports} new geofence events";
}
Helpers.DisplayToast(description);
}
}
