public async Task <Position> GetPositionAsync(TimeSpan?timeout = null, CancellationToken?cancelToken = null)
{
var timeoutMilliseconds = timeout.HasValue ? (int)timeout.Value.TotalMilliseconds : Timeout.Infinite;
if (timeoutMilliseconds <= 0 && timeoutMilliseconds != Timeout.Infinite)
{
throw new ArgumentOutOfRangeException(nameof(timeout), "Timeout must be greater than or equal to 0");
}
if (!cancelToken.HasValue)
{
cancelToken = CancellationToken.None;
}
var hasPermission = await CheckPermissionsAsync();
if (!hasPermission)
{
throw new GeolocationException(GeolocationError.Unauthorized);
}
var tcs = new TaskCompletionSource <Position>();
var providers = new List <string>();
if (ProvidersToUse == null || ProvidersToUse.Length == 0)
{
providers.AddRange(Providers);
}
else
{
foreach (var provider in Providers)
{
if (ProvidersToUse?.Contains(provider) ?? false)
{
continue;
}
providers.Add(provider);
}
}
void SingleListenerFinishCallback()
{
if (_singleListener == null)
{
return;
}
for (int i = 0; i < providers.Count; ++i)
{
Manager.RemoveUpdates(_singleListener);
}
}
_singleListener = new GeolocationSingleListener(Manager, (float)DesiredAccuracy, timeoutMilliseconds, providers.Where(Manager.IsProviderEnabled), finishedCallback: SingleListenerFinishCallback);
if (cancelToken != CancellationToken.None)
{
cancelToken.Value.Register(() =>
{
_singleListener.Cancel();
for (int i = 0; i < providers.Count; ++i)
{
Manager.RemoveUpdates(_singleListener);
}
}, true);
}
try
{
var looper = Looper.MyLooper() ?? Looper.MainLooper;
int enabled = 0;
for (var i = 0; i < providers.Count; ++i)
{
if (Manager.IsProviderEnabled(providers[i]))
{
enabled++;
}
Manager.RequestLocationUpdates(providers[i], 0, 0, _singleListener, looper);
}
if (enabled == 0)
{
for (int i = 0; i < providers.Count; ++i)
{
Manager.RemoveUpdates(_singleListener);
}
tcs.SetException(new GeolocationException(GeolocationError.PositionUnavailable));
return(await tcs.Task);
}
}
catch (Java.Lang.SecurityException ex)
{
tcs.SetException(new GeolocationException(GeolocationError.Unauthorized, ex));
return(await tcs.Task);
}
return(await _singleListener.Task);
}
/// <summary>
/// Gets position async with specified parameters
/// </summary>
/// <param name="timeout">Timeout to wait, Default Infinite</param>
/// <param name="cancelToken">Cancelation token</param>
/// <param name="includeHeading">If you would like to include heading</param>
/// <returns>Position</returns>
public async Task <Position> GetPositionAsync(TimeSpan?timeout, CancellationToken?cancelToken = null, bool includeHeading = false)
{
var timeoutMilliseconds = timeout.HasValue ? (int)timeout.Value.TotalMilliseconds : Timeout.Infinite;
if (timeoutMilliseconds <= 0 && timeoutMilliseconds != Timeout.Infinite)
{
throw new ArgumentOutOfRangeException(nameof(timeout), "timeout must be greater than or equal to 0");
}
if (!cancelToken.HasValue)
{
cancelToken = CancellationToken.None;
}
var hasPermission = await CheckWhenInUsePermission();
if (!hasPermission)
{
throw new GeolocationException(GeolocationError.Unauthorized);
}
var tcs = new TaskCompletionSource <Position>();
if (!IsListening)
{
var providers = new List <string>();
if (ProvidersToUse == null || ProvidersToUse.Length == 0)
{
providers.AddRange(Providers);
}
else
{
//only add providers requested.
foreach (var provider in Providers)
{
if (ProvidersToUse == null || !ProvidersToUse.Contains(provider))
{
continue;
}
providers.Add(provider);
}
}
void SingleListnerFinishCallback()
{
if (singleListener == null)
{
return;
}
for (var i = 0; i < providers.Count; ++i)
{
Manager.RemoveUpdates(singleListener);
}
}
singleListener = new GeolocationSingleListener(Manager,
(float)DesiredAccuracy,
timeoutMilliseconds,
providers.Where(Manager.IsProviderEnabled),
finishedCallback: SingleListnerFinishCallback);
if (cancelToken != CancellationToken.None)
{
cancelToken.Value.Register(() =>
{
singleListener.Cancel();
for (var i = 0; i < providers.Count; ++i)
{
Manager.RemoveUpdates(singleListener);
}
}, true);
}
try
{
var looper = Looper.MyLooper() ?? Looper.MainLooper;
var enabled = 0;
for (var i = 0; i < providers.Count; ++i)
{
if (Manager.IsProviderEnabled(providers[i]))
{
enabled++;
}
Manager.RequestLocationUpdates(providers[i], 0, 0, singleListener, looper);
}
if (enabled == 0)
{
for (int i = 0; i < providers.Count; ++i)
{
Manager.RemoveUpdates(singleListener);
}
tcs.SetException(new GeolocationException(GeolocationError.PositionUnavailable));
return(await tcs.Task);
}
}
catch (Java.Lang.SecurityException ex)
{
tcs.SetException(new GeolocationException(GeolocationError.Unauthorized, ex));
return(await tcs.Task);
}
return(await singleListener.Task);
}
// If we're already listening, just use the current listener
lock (positionSync)
{
if (lastPosition == null)
{
if (cancelToken != CancellationToken.None)
{
cancelToken.Value.Register(() => tcs.TrySetCanceled());
}
EventHandler <PositionEventArgs> gotPosition = null;
gotPosition = (s, e) =>
{
tcs.TrySetResult(e.Position);
PositionChanged -= gotPosition;
};
PositionChanged += gotPosition;
}
else
{
tcs.SetResult(lastPosition);
}
}
return(await tcs.Task);
}