CODEWITHSUNDEEP
multithreadingxamarinxamarin.formsxamarin.iosbackground-process
user2850818
user2850818

Reputation: 415

System.Threading.Timer not firing

I'm writing an app that will send location data every x seconds, and run in the background. I'm calling the following method.

    public void StartListening()
    {
        UpdateGpsService();
        if(CLLocationManager.LocationServicesEnabled)
        {
            locationManager.DesiredAccuracy = 10;

            nint taskId = UIApplication.SharedApplication.BeginBackgroundTask(() =>
           {
               timer = new Timer((o) =>
               {
                   CLLocation location = locationManager.Location;
                   Nmea nmea = new IOSNmea(location);
                   Gprmc gprmc = new Gprmc();
                   gprmc.url = this.Url;
                   gprmc.Id = this.DeviceId;
                   gprmc.GprmcString = nmea.ToString();

               }, null, 0, UpdateInterval * 1000);
           });

            App.Database.SaveItemAsync(new TodoItem() { key = LOCATOR_SERVICE_ID, value = taskId.ToString() });
        }
    }

However, it doesn't seem to be calling the code inside the timer callback. I tried putting a breakpoint in there, and it never gets called. Is there something obviously wrong with my code? Thanks for any help.

Upvotes: 0

Views: 151

Answers (1)

SushiHangover
SushiHangover

Reputation: 74209

BeginBackgroundTask only tells iOS that you are starting a long running task and the handler is not for the execution of that task, BUT it is a completion handler that is called when the OS is about to shut it down...

Timer timer = null;
nint taskId = UIApplication.SharedApplication.BeginBackgroundTask(() =>
{
    // Clean up as the background task is begin shutdown by iOS
    timer?.Dispose();
});
timer = new Timer((o) =>
{
    Console.WriteLine("Timer Update");
}, null, TimeSpan.Zero, TimeSpan.FromSeconds(1));

// Must call EndBackgroundTask when you are done with this...
// UIApplication.SharedApplication.EndBackgroundTask(taskId);

Upvotes: 1

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