Question

我知道如何通过使用纬度和经度让地图显示在地图上，但我遇到的麻烦就是让当前的位置显示出来。

我已经按照教程： https://www.youtube.com/watch?v=cx5O9GfOnS4

但是，当我尝试做位置。长度＆＃34;或＆＃34; position.Latitude＆＃34;，第34行，它表示无法找到该位置。我需要帮助来尝试修复此错误并了解如何使其正常工作。

using Plugin.Geolocator;
using System;
using Xamarin.Forms;
using Xamarin.Forms.Maps;

namespace WorkingWithMaps
{
    public class PinPage : ContentPage
    {
        Map map;

        public PinPage()
        {
            map = new Map {
                IsShowingUser = true,
                HeightRequest = 100,
                WidthRequest = 960,
                VerticalOptions = LayoutOptions.FillAndExpand


            };

            var locator = CrossGeolocator.Current;
            locator.DesiredAccuracy = 50;
            var position = locator.GetPositionAsync(timeoutMilliseconds: 10000);
            map.MoveToRegion (MapSpan.FromCenterAndRadius (


            new Position (position.Longitude, position.Latitude), Distance.FromMiles (1))); // current pos

            //var position = new Position(-26.077740, 28.010100); // Latitude, Longitude

            var pin = new Pin {
                Type = PinType.Place,
                //Position = position,
                Label = "Test",
                Address = "Test..."
            };
            map.Pins.Add(pin);

            //this works but I need current location not hard coded lat/lng   
            //map.MoveToRegion (MapSpan.FromCenterAndRadius (
            //new Position (-26.077740, 28.010100), Distance.FromMiles (1))); // S4C location

            //var position = new Position(-26.077740, 28.010100); // Latitude, Longitude
            //  var pin = new Pin {
            //  Type = PinType.Place,
            //  Position = position,
            //  Label = "Test",
            //  Address = "Test..."
            //  };
            //  map.Pins.Add(pin);


            // create buttons
            var morePins = new Button { Text = "Show Pins Near Me" };
            morePins.Clicked += (sender, e) => {
                map.Pins.Add(new Pin {
                    Position = new Position(-26.074932, 28.012136),
                    Label = "123"
                });
                map.Pins.Add(new Pin {
                    Position = new Position(-26.080752, 28.026094),
                    Label = "321"
                });
                map.MoveToRegion (MapSpan.FromCenterAndRadius (
                    new Position (-26.077740, 28.010100), Distance.FromMiles (2))); // this distance shows dealerships to current position

            };
            var reLocate = new Button { Text = "Re-center" };
            reLocate.Clicked += (sender, e) => {
                map.MoveToRegion (MapSpan.FromCenterAndRadius (
                    new Position (-26.077740, 28.010100), Distance.FromMiles (0.5)));
            };
            var buttons = new StackLayout {
                Orientation = StackOrientation.Horizontal,
                Children = {
                    morePins, reLocate
                }
            };

            // put the page together
            Content = new StackLayout { 
                Spacing = 0,
                Children = {
                    map,
                    buttons
                }
            };
        }
    }
}

编辑：新代码 目前的问题： *它没有显示我当前的位置，并将其与＆＃34;测试＆＃34;显示＆＃34;当前位置＆＃34;之间距离的位置和他们。

请注意，如果我使用坐标，例如。（022225,555552）而不是＆＃34; position.Longitude，position.Latitude＆＃34;然后它工作，但它不用于GPS来获取我当前的位置。请告知我出错的地方以及如何解决。

这是新代码：

using Plugin.Geolocator;
using System;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Maps;

namespace WorkingWithMaps
{
public class PinPage : ContentPage
{

    Map map;



    public PinPage()
    {
        map = new Map {
            IsShowingUser = true,
            HeightRequest = 100,
            WidthRequest = 960,
            VerticalOptions = LayoutOptions.FillAndExpand



        }; }

        protected async override void OnAppearing()
    {

        // create buttons


            var morePins = new Button { Text = "Show Tests Near Me" };
            //current pos
            var locator = CrossGeolocator.Current;
            locator.DesiredAccuracy = 50;


            var position = await locator.GetPositionAsync(timeoutMilliseconds: 10000);
            var reLocate = new Button { Text = "Re-center" };
            reLocate.Clicked += (sender, e) => {
            map.MoveToRegion(MapSpan.FromCenterAndRadius(
            new Position(position.Longitude, position.Latitude), Distance.FromMiles(0.5)));


            };


            var buttons = new StackLayout
            {
                Orientation = StackOrientation.Horizontal,
                Children = {
                morePins, reLocate
            }
            };

            morePins.Clicked += (sender, e) => {
            map.Pins.Add(new Pin {
                Position = new Position(-26.074932, 28.012136),
                Label = "Test 1"

            });
            map.Pins.Add(new Pin {
                Position = new Position(-26.080752, 28.026094),
                Label = "Test 2"
            });
            map.MoveToRegion(MapSpan.FromCenterAndRadius(
            new Position(position.Longitude, position.Latitude), Distance.FromMiles(2))); // this distance shows tests to current position

            };


        // put the page together
        Content = new StackLayout { 
            Spacing = 0,
            Children = {
                map,
                buttons
            }};

        }
    }
    }

固定： 我有lat和长期交换的顺序，这就是为什么它没有找到我的位置。愚蠢的错误。感谢大家的投入！

Answer 1

您将获得async method所需的职位{/ 1}}。

await

但是，这种单一更改在您的情况下不起作用，因为您需要将构造函数标记为var position = await locator.GetPositionAsync(timeoutMilliseconds: 10000);，这是不可能的。

但您可以覆盖async并将其设为异步：

OnAppearing

Answer 2

在将结果传递到locator.GetPositionAsync(timeoutMilliseconds: 10000);之前，您需要等待map。像这样的东西 -

Task.Run(async () =>
        {
            var position = await locator.GetPositionAsync(timeoutMilliseconds: 10000);
            map.MoveToRegion (MapSpan.FromCenterAndRadius (


            new Position (position.Longitude, position.Latitude), Distance.FromMiles (1))); // current pos

            //var position = new Position(-26.077740, 28.010100); // Latitude, Longitude

            var pin = new Pin {
                Type = PinType.Place,
                //Position = position,
                Label = "Test",
                Address = "Test..."
            };
            map.Pins.Add(pin);
        });

获取当前位置图钉以显示在地图上

2 个答案: