Question

我正在使用Xamarin Forms创建一个跟踪用户位置的应用。我目前正在尝试使用this Geolocator插件来跟踪用户的位置。我已经按照插件教程中的步骤进行了操作，但我的位置目前还没有刷新。

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，所以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，有点难以回答你的问题。位置插件（例如GeoLocation）需要在项目中设置一些属性（权限）。你加了那些吗？你在哪个平台上使用它？在什么设备或模拟器上测试它？

Answer 2

我已经实现了相同的库以下是我的代码完美地在Android和iOS上工作

     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("\n\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.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)));

                });
            }
        }
    }

C＃Xamarin Geolocator插件没有更新位置

2 个答案: