Question

使用Xamarin表格进行简单的地图跟踪，地图一直闪烁：

 public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();

            GetCurrentPosition();
        }
        public async void GetCurrentPosition()
        {
            var locator = CrossGeolocator.Current;
            locator.DesiredAccuracy = 50;

            locator.PositionChanged += (s, e) =>
            {
                var map = new Map(
                MapSpan.FromCenterAndRadius(
                    new Position(e.Position.Latitude, e.Position.Longitude), Distance.FromMiles(0.3)))
                {
                    IsShowingUser = true,
                    HeightRequest = 100,
                    WidthRequest = 960,
                    VerticalOptions = LayoutOptions.FillAndExpand
                };
                var stack = new StackLayout { Spacing = 0 };
                stack.Children.Add(map);
                Content = stack;
            };

            if (!locator.IsListening)
            {
                await locator.StartListeningAsync(1000, 0);
            }
        }
    }

我该如何解决？

Answer 1

这是正常的。这是因为每次更新位置时，您都会创建一个添加到页面的新地图（因此闪烁）。相反，您应该保留地图的相同实例并更新此地图的位置。

你可以试试这个：

public partial class MainPage : ContentPage
    {        
        private Map _map;
        public MainPage()
        {
            InitializeComponent();
            _map = new Map
            {
                IsShowingUser = true,
                HeightRequest = 100,
                WidthRequest = 960,
                VerticalOptions = LayoutOptions.FillAndExpand
            };
            var stack = new StackLayout { Spacing = 0 };
            stack.Children.Add(_map);
            Content = stack;
            GetCurrentPosition();
        }
        public async void GetCurrentPosition()
        {
            var locator = CrossGeolocator.Current;
            locator.DesiredAccuracy = 50;

            locator.PositionChanged += (s, e) =>
            {
                _map.MoveToRegion(
                MapSpan.FromCenterAndRadius(
                    new Position(e.Position.Latitude, e.Position.Longitude), Distance.FromMiles(0.3)));
            };

            if (!locator.IsListening)
            {
                await locator.StartListeningAsync(1000, 0);
            }
        }
    }

谷歌地图在听取位置时闪烁

1 个答案: