Xamarin Forms 代码已过时的问题

Question

我尝试使用 Xamarin.Forms 在我的应用中使用地图功能。

在这部分代码中，我获得了允许在地图中查看我的位置的权限。

[Obsolete]
private async void GetPermession()
{
        try
        {
            var status = await CrossPermissions.Current.CheckPermissionStatusAsync(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse);
            //var status = await CrossPermissions.Current.CheckPermissionStatusAsync<LocationWhenInUsePermission>();

            if (status != Plugin.Permissions.Abstractions.PermissionStatus.Granted)
            {
                if (await CrossPermissions.Current.ShouldShowRequestPermissionRationaleAsync(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse))
                {
                    await
                        DisplayAlert("Need your location", "We need to acces your location", "Ok");
                }

                var result = await CrossPermissions.Current.RequestPermissionsAsync(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse);

                if (result.ContainsKey(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse))
                    status = result[Plugin.Permissions.Abstractions.Permission.LocationWhenInUse];
            }

            if (status == Plugin.Permissions.Abstractions.PermissionStatus.Granted)
                this.LocationMap.IsShowingUser = true;
            else
                await
                    DisplayAlert("Need your location", "We need to acces your location", "Ok");

        }
        catch (Exception exception)
        {
            await
                DisplayAlert("Error", exception.Message, "Ok");
        }
}

Visual Studio 告诉我

CrossPermissions.Current.ShouldShowRequestPermissionRationaleAsync(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse)) 已过时，新方法为：

CrossPermissions.Current.ShouldShowRequestPermissionRationaleAsync()

但是，如果我使用新方法

var result = await CrossPermissions.Current.RequestPermissionsAsync(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse);

if (result.ContainsKey(Plugin.Permissions.Abstractions.Permission.LocationWhenInUse))
    status = result[Plugin.Permissions.Abstractions.Permission.LocationWhenInUse];

结果没有.ContainsKey 方法。

我该如何解决这个问题？

对不起，我的英语不好，谢谢

Answer 1

    public async void GetPermission()
    {
        var permission = await Permissions.CheckStatusAsync<Permissions.LocationWhenInUse>();

        if (permission != PermissionStatus.Granted)
        {
            permission = await Permissions.RequestAsync<Permissions.LocationWhenInUse>();
        }
        else if(permission == PermissionStatus.Granted)
            this.LocationMap.IsShowingUser = true;

        if (permission != PermissionStatus.Granted)
            return;
    }

我用这个方法解决了，谢谢大家的回答

Answer 2

您可以像这样使用 Xamarin.Essential 和 Dependency 服务获取权限：

界面

public interface IPermissionHelper
{  
   Task<PermissionStatus> RequestPermissionsAsync();
}

从共享项目中调用它：

await DependencyService.Get<IPermissionHelper>().RequestPermissionsAsync();

iOS 渲染器：

public class PermissionHelper : IPermissionHelper
{
    public PermissionHelper()
    {
    }

    /// <summary>
    /// Defines the showTrackingMap.
    /// </summary>
    LocationCheck showTrackingMap;

    /// <summary>
    /// The RequestPermissionsAsync.
    /// </summary>
    /// /// <returns>The <see cref="Task<PermissionStatus>"/>.</returns>
    public async Task<PermissionStatus> RequestPermissionsAsync()
    {
        PermissionStatus permission = PermissionStatus.Unknown;
        showTrackingMap = new LocationCheck((s, ev) => {
            if ((ev as LocationCheck.LocationCheckEventArgs).Allowed)
            {
                permission = PermissionStatus.Granted;
            }
            else
            {
                permission = PermissionStatus.Denied;
            }
            showTrackingMap.Dispose();
        });

        while (permission == PermissionStatus.Unknown)
        {
            await Task.Delay(10);
        }

        return permission;
    }
}

public class LocationCheck : NSObject, ICLLocationManagerDelegate
{
    public class LocationCheckEventArgs : EventArgs
    {
        public readonly bool Allowed;
        public LocationCheckEventArgs(bool Allowed)
        {
            this.Allowed = Allowed;
        }
    }

    CLLocationManager locationManager;
    EventHandler locationStatus;

    public LocationCheck(EventHandler locationStatus)
    {
        this.locationStatus = locationStatus;
        Initialize();
    }

    public LocationCheck(NSObjectFlag x) : base(x) { Initialize(); }

    public LocationCheck(IntPtr handle) : base(handle) { Initialize(); }

    public LocationCheck(IntPtr handle, bool alloced) : base(handle, alloced) { Initialize(); }

    public void Initialize()
    {
        locationManager = new CLLocationManager
        {
            Delegate = this
        };
        locationManager.RequestWhenInUseAuthorization();
    }

    [Export("locationManager:didChangeAuthorizationStatus:")]
    public void AuthorizationChanged(CLLocationManager manager, CLAuthorizationStatus status)
    {
        switch (status)
        {
            case CLAuthorizationStatus.AuthorizedAlways:
            case CLAuthorizationStatus.AuthorizedWhenInUse:
                locationStatus.Invoke(locationManager, new LocationCheckEventArgs(true));
                break;
            case CLAuthorizationStatus.Denied:
            case CLAuthorizationStatus.Restricted:
                locationStatus.Invoke(locationManager, new LocationCheckEventArgs(false));
                break;
        }
    }

    protected override void Dispose(bool disposing)
    {
        locationStatus = null;
        locationManager.Delegate = null;
        locationManager.Dispose();
        base.Dispose(disposing);
    }
}