C# Xamarin 地理定位器插件未更新位置

Question

我正在使用Xamarin Forms创建一个应用程序，该应用程序可以跟踪用户的位置。我目前正在尝试使用此Geolocator插件来跟踪用户的位置。我已经按照插件教程中的步骤操作，但我的位置目前没有刷新。

这是我的代码：

public WhosOnFarm ()
{
InitializeComponent ();
locator = CrossGeolocator.Current;
locator.PositionChanged += (sender, e) => {
DisplayAlert("Success", "Your position has changed!", "OK");
var position = e.Position;
longitudeLabel.Text = "Longitude: "+position.Longitude.ToString() + " Latitude: " + position.Latitude.ToString();
};
}

在教程中，它没有指定locator的类型，因此我假设它需要的数据CrossGeolocator.Current;

我错过了什么？

Answer 1

如果没有项目设置，回答您的问题有点困难。位置插件(如地理位置(需要在项目中设置某些属性(权限(。你添加了这些吗？您在哪个平台上使用它？您在什么设备或模拟器上对其进行了测试？

Answer 2

我已经实现了相同的库，以下是我的代码 完美地在安卓和iOS上运行

public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
CrossGeolocator.Current.AllowsBackgroundUpdates = true;
CrossGeolocator.Current.DesiredAccuracy = 50;
CrossGeolocator.Current.PositionChanged += Current_PositionChanged;
}
protected override void OnAppearing()
{
base.OnAppearing();
updateLocation();
}
private async void updateLocation()
{
try
{
var locator = CrossGeolocator.Current;
locator.DesiredAccuracy = 50;
locator.AllowsBackgroundUpdates = true;
var position = await locator.GetPositionAsync(timeoutMilliseconds: 10000);
if (position == null)
{
lblData.Text = "null gps :(";
return;
}
lblData.Text = string.Format("nTime: {0} nLat: {1} nLong: {2} n Altitude: {3} nAltitude Accuracy: {4} nAccuracy: {5} n Heading: {6} n Speed: {7}",
position.Timestamp, position.Latitude, position.Longitude,
position.Altitude, position.AltitudeAccuracy, position.Accuracy, position.Heading, position.Speed);
mapVar.MoveToRegion(
MapSpan.FromCenterAndRadius(
new Position(position.Latitude,position.Longitude), Distance.FromKilometers(1)));
await CrossGeolocator.Current.StartListeningAsync(1, 2, true);
}
catch (Exception)
{
}
}

private void Current_PositionChanged(object sender, Plugin.Geolocator.Abstractions.PositionEventArgs e)
{
if (e.Position != null)
{
Device.BeginInvokeOnMainThread(() => {
var position = e.Position;
lblData.Text = string.Format("nnTime: {0} nLat: {1} nLong: {2} n Altitude: {3} nAltitude Accuracy: {4} nAccuracy: {5} n Heading: {6} n Speed: {7}",
position.Timestamp, position.Latitude, position.Longitude,
position.Altitude, position.AltitudeAccuracy, position.Accuracy, position.Heading, position.Speed);
mapVar.Pins.Clear();
mapVar.Pins.Add(new Xamarin.Forms.Maps.Pin
{
Position = new Xamarin.Forms.Maps.Position(position.Latitude, position.Longitude),
Type = Xamarin.Forms.Maps.PinType.Place,
Label = "My Location"
});
mapVar.MoveToRegion(
MapSpan.FromCenterAndRadius(
new Position(position.Latitude, position.Longitude), Distance.FromKilometers(1)));
});
}
}
}