Permissions API's

[Redth]

Check and Request permissions.

Internally we need to ensure we have API’s for a couple of things:

• internal bool EnsurePermissionDeclared (string permission) checks if Info.plist on iOS, or AndroidManifest.xml, or x on UWP has the permission declared/defined and throws an exception with a meaningful error message including a link to documentation of how to ensure permissions are defined in the appropriate file for the given platform at runtime.

Permissions

public static class Permissions 
{
    public static Task<PermissionStatus> CheckPermissionAsync (string permission);
    public static Task<IDictionary<string, PermissionStatus>> CheckPermissionsAsync (params string[] permissions);

    public static Task<PermissionStatus> RequestPermissionAsync (string permission);
    public static Task<IDictionary<string, PermissionStatus>> RequestPermissionsAsync (params string[] permissions);
}

PermissionStatus (enum)

public enum PermissionStatus {
    Unknown,
    Denied,
    Disabled,
    Restricted,
    Granted,
}

[Redth]

I think we also need some helper properties/static readonly fields that return the correct string permission for a given platform:

This is not how I'd want the actual implementation to be, but to illustrate the idea:

public static class PermissionType
{
#if __ANDROID__
    public static readonly Camera = "android.permission.CAMERA";
#elif __IOS__
    public static readonly Camera = "Camera";
#elif __UWP__
    public static readonly Camera = "Camera";
#endif
}

So that the user can call the api's more sanely splat:

await Permissions.RequestPermissionAsync(PermissionType.Camera);

[Redth]

I may be changing my mind on this a bit now. Looking at iOS and UWP, they both have different code paths depending on which permission has been requested, unlike Android which is just a string to identify the permission.

I'm starting to think an enum was already the best choice here.