Speed not always returned for iOS

[mjorrens]

Bug Information

Version Number of Plugin: 4.5.0.6 Device Tested On: iPhone 6S with OS 11.4 Simulator Tested On: Version of VS: 2017 For PC Version of Xamarin: 3.0.0.550 Versions of other things you are using:

Steps to reproduce the Behavior

• Run the GeolocatorSample
• Tap on the "Tracking" tab
• Tap on "Track Movement" button
• Walk around with the device to get some updates
• You will see the Speed property always remains at 0 (need to scroll down in the upper section to see this on the phone).

Now try this:

• Run the GeolocatorSample
• Tap on the "Try It" tab
• Set the "Desired Accuracy" to 10 meters
• Tap on "Get Current Location" --> wait to see the current location appear.
• Tap on the "Tracking" tab
• Tap on "Track Movement" button
• Walk around with the device to get some updates
• The Speed now gets updated properly

Expected Behavior_

The speed should appear as it always does on Android.

Actual Behavior

There seems to be an initial condition problem here. If you call

locator.DesiredAccuracy = DesiredAccuracy.Value; var position = await locator.GetPositionAsync(TimeSpan.FromSeconds(Timeout.Value), null, IncludeHeading.IsToggled);

First with the accuracy at 10meters and THEN listen via StartListeningAsync() all works fine and you get the speed.

I did try to set the DesiredAccuracy before for the StartListeningAsync at 10meters but that did not work which makes me believe that GetPositionAsync sets some initial condition properly.

Code snippet

• See Sample Code for Geolocator on GitHub

Screenshots

• None

[mjorrens]

The fix:

Set the DesiredAccuracy: CrossGeolocator.Current.DesiredAccuracy = DesiredAccuracy.Value;

Before calling the listener: if (await CrossGeolocator.Current.StartListeningAsync(TimeSpan.FromSeconds(TrackTimeout.Value), TrackDistance.Value, ...

This is in ButtonTrack_Clicked()

I misspoke in my comment above about trying this and it not working...it does correct the problem. Note the accuracy needs to be 10 meters for the speed to appear properly.

[jamesmontemagno]

I return what apple returns and nothing else I can do.

[mjorrens]

Agreed. Perhaps you update the sample code though with my change above so other folks don't get the problem.

Thanks.