Platform

IPlatform is the small cross-platform surface every Shiny module uses to find a place for files and to get onto the UI thread. Inject it anywhere:

public interface IPlatform
{
    void InvokeOnMainThread(Action action);
    DirectoryInfo AppData { get; }
    DirectoryInfo Cache { get; }
    DirectoryInfo Public { get; }
}

Directories

Platform	AppData	Cache	Public
Android	Context.FilesDir	Context.CacheDir	GetExternalFilesDir(null) (can be null if external storage is unavailable)
iOS / tvOS / Mac Catalyst	Library	Library/Caches	Documents
macOS (AppKit)	Library	Library/Caches	Documents
Windows (packaged)	ApplicationData.Current.LocalFolder	LocalFolder/Cache	LocalFolder/Public
Windows (unpackaged) / plain .NET	LocalApplicationData/<entry assembly>	…/Cache	…/Public

On Linux, LocalApplicationData resolves to $XDG_DATA_HOME (falling back to ~/.local/share), so the plain .NET layout already follows XDG. The folder is named after the entry assembly so that apps don’t write into a directory the whole desktop shares.

ResourceToFilePath(assembly, resourceName) copies an embedded resource into AppData the first time it is asked for, then returns the path. Use it for native APIs that only accept a file, such as a bundled database or model.

Main Thread

InvokeOnMainThread runs the action inline if you are already on the main thread and posts it otherwise. The extensions in PlatformExtensions add async versions that complete when the work has run and pass exceptions back to the caller:

await platform.InvokeOnMainThreadAsync(() => label.Text = "Done");
var result = await platform.InvokeOnMainThreadAsync(() => ReadSomeUiState());

// async work that must start on the UI thread
await platform.InvokeTaskOnMainThread(async () => await ShowDialogAsync(), cancellationToken);

Windows and plain .NET have no toolkit-independent main thread, so WindowsPlatform.MainThreadHandler and NetPlatform.MainThreadHandler are static hooks for the hosting layer to set. UseShiny() sets the Windows hook to the WinUI dispatcher. A GTK or other desktop head should set the NetPlatform hook to its own main loop:

NetPlatform.MainThreadHandler = action => GLib.Idle.Add(() => { action(); return false; });

If nothing sets the handler, the action runs inline. Code with no UI thread still works; it just isn’t marshalled.

Android — AndroidPlatform

Resolve the concrete AndroidPlatform (or use Host.Platform) for the Android-specific helpers Shiny’s modules are built on.

Runtime permissions

var result = await platform.RequestPermissions(
    Manifest.Permission.AccessFineLocation,
    Manifest.Permission.AccessCoarseLocation
);
if (!result.IsSuccess())
{
    var fineGranted = result.IsGranted(Manifest.Permission.AccessFineLocation);
}

// single permission, mapped to AccessState
var state = await platform.RequestAccess(Manifest.Permission.Camera);

// no prompt, just the current state
var current = platform.GetCurrentPermissionStatus(Manifest.Permission.Camera);

• If every permission is already granted, the request returns immediately without showing a dialog.
• A request needs a foreground Activity. If none is up yet (for example, the request fired during startup), Shiny waits up to 5 seconds for one to resume and then throws TimeoutException. That timeout applies only to getting an activity. Once the dialog is showing, the user can take as long as they want. Pass a CancellationToken to give up yourself.
• GetCurrentPermissionStatus returns Unknown rather than Denied for a permission the app has never requested. Shiny records requested permissions in the default store so that the distinction survives a restart.
• RequestFilteredPermissions(params AndroidPermission[]) and EnsureAllManifestEntries(...) take AndroidPermission(permission, minSdk, maxSdk) records and skip entries that don’t apply to the running API level. Use them for permissions that were added or retired across Android versions.
• IsInManifest(permission) checks the merged manifest.

Activities

Member	Description
CurrentActivity	The most recently active Activity, or null
ActivityChanged	Event raised with an ActivityChanged(Activity, ActivityState, Bundle?) for Created, Started, Resumed, Paused, Stopped, SaveInstanceState and Destroyed
WaitForActivity(state, ct)	Completes the next time any activity reaches state (Resumed by default)

Services, intents and resources

Member	Description
AppContext	The Android Application
StartService(type, stopWithTask) / StopService(type)	Start or stop a Shiny foreground service. Uses StartForegroundService on API 31+
RequestForegroundServicePermissions()	Requests FOREGROUND_SERVICE and, on API 33+, POST_NOTIFICATIONS. Returns Restricted when only the notification permission was refused
CreateIntent<T>(actions) / GetBroadcastPendingIntent<T>(...)	Intent helpers. GetPendingIntentFlags adds Mutable on API 31+
RegisterBroadcastReceiver<T>(exported, actions)	Registers a receiver with the exported flag Android 14 requires
GetSystemService<T>(name) / GetSystemServiceValue(...)	Typed system-service access
GetNotificationIconResource()	Returns the notification drawable, or the app icon if there isn’t one. Throws if neither exists
GetResourceIdByName, GetColorByName, GetRawResourceIdByName	Resource lookups by name

Apple — IosPlatform and AppleExtensions

IosPlatform (iOS, tvOS, Mac Catalyst) adds AppIdentifier, which returns the bundle identifier. AppleExtensions collects the helpers Shiny’s Apple backends use:

Member	Description
IsSimulator	true on the iOS/tvOS simulator, always false on Mac Catalyst/macOS
HasBackgroundMode("location")	Checks UIBackgroundModes in Info.plist
AssertInfoPlistEntry(key, assert) / HasPlistValue(key, ifVersion)	Info.plist checks, optionally only from an OS version onward
HasAppDelegateHook(selector) / AssertAppDelegateHook(...)	Checks that the AppDelegate implements a selector, for example didRegisterForRemoteNotificationsWithDeviceToken
ToDateTime() / ToNSDate()	NSDate conversions (Apple’s reference date is 2001-01-01 UTC)
ToGuid() / ToNSUuid()	NSUuid conversions
FromNsDictionary() / ToNsDictionary()	String dictionary conversions

Windows

Shiny.Permissions.IsInMainfest(capability) reads AppxManifest.xml to check whether a DeviceCapability is declared. It only applies to packaged apps.