Speech Recognition Windows Ensure unsubscribe from events on Stop Recording

samples/CommunityToolkit.Maui.Sample/Platforms/Windows/Package.appxmanifest

@@ -57,6 +57,7 @@
 
     <Capabilities>
         <rescap:Capability Name="runFullTrust" />
+        <DeviceCapability Name="microphone"/>
     </Capabilities>
 
 </Package>

samples/CommunityToolkit.Maui.Sample/ViewModels/Essentials/SpeechToTextViewModel.cs

@@ -8,11 +8,9 @@
 
 namespace CommunityToolkit.Maui.Sample.ViewModels.Essentials;
 
-public partial class SpeechToTextViewModel : BaseViewModel
+public partial class SpeechToTextViewModel : BaseViewModel, IAsyncDisposable
 {
 	const string defaultLanguage = "en-US";
-	const string defaultLanguage_android = "en";
-	const string defaultLanguage_tizen = "en_US";
 
 	readonly ITextToSpeech textToSpeech;
 	readonly ISpeechToText speechToText;
@@ -55,7 +53,7 @@ async Task SetLocales(CancellationToken token)
 			Locales.Add(locale);
 		}
 
-		CurrentLocale = Locales.FirstOrDefault(x => x.Language is defaultLanguage or defaultLanguage_android or defaultLanguage_tizen) ?? Locales.FirstOrDefault();
+		CurrentLocale = Locales.FirstOrDefault();
 	}
 
 	[RelayCommand]
@@ -148,4 +146,9 @@ void HandleLocalesCollectionChanged(object? sender, NotifyCollectionChangedEvent
 	{
 		OnPropertyChanged(nameof(CurrentLocale));
 	}
+
+	public async ValueTask DisposeAsync()
+	{
+		await speechToText.DisposeAsync();
+	}
 }

src/CommunityToolkit.Maui.Core/Essentials/SpeechToText/OfflineSpeechToTextImplementation.windows.cs

@@ -28,9 +28,6 @@ public SpeechToTextState CurrentState
 	public ValueTask DisposeAsync()
 	{
 		InternalStopListening();
-
-		offlineSpeechRecognizer?.Dispose();
-		offlineSpeechRecognizer = null;
 		return ValueTask.CompletedTask;
 	}
 
@@ -39,7 +36,6 @@ Task InternalStartListening(SpeechToTextOptions options, CancellationToken token
 		Initialize(options);
 
 		offlineSpeechRecognizer.AudioStateChanged += OfflineSpeechRecognizer_StateChanged;
-		offlineSpeechRecognizer.LoadGrammar(new DictationGrammar());
 
 		offlineSpeechRecognizer.InitialSilenceTimeout = TimeSpan.MaxValue;
 		offlineSpeechRecognizer.BabbleTimeout = TimeSpan.MaxValue;
@@ -48,7 +44,12 @@ Task InternalStartListening(SpeechToTextOptions options, CancellationToken token
 
 		offlineSpeechRecognizer.RecognizeCompleted += OnRecognizeCompleted;
 		offlineSpeechRecognizer.SpeechRecognized += OnSpeechRecognized;
-		offlineSpeechRecognizer.RecognizeAsync(RecognizeMode.Multiple);
+
+		if (offlineSpeechRecognizer.AudioState == AudioState.Stopped)
+		{
+			offlineSpeechRecognizer.RecognizeAsync(RecognizeMode.Multiple);
+		}
+
 		return Task.CompletedTask;
 	}
 
@@ -81,19 +82,26 @@ void InternalStopListening()
 	{
 		try
 		{
-			if (offlineSpeechRecognizer is not null)
+			if (offlineSpeechRecognizer is not null && offlineSpeechRecognizer.AudioState != AudioState.Stopped)
 			{
 				offlineSpeechRecognizer.RecognizeAsyncStop();
-
-				offlineSpeechRecognizer.AudioStateChanged -= OfflineSpeechRecognizer_StateChanged;
-				offlineSpeechRecognizer.RecognizeCompleted -= OnRecognizeCompleted;
-				offlineSpeechRecognizer.SpeechRecognized -= OnSpeechRecognized;
 			}
 		}
 		catch
 		{
 			// ignored. Recording may be already stopped
 		}
+		finally
+		{
+			if (offlineSpeechRecognizer is not null)
+			{
+				offlineSpeechRecognizer.AudioStateChanged -= OfflineSpeechRecognizer_StateChanged;
+				offlineSpeechRecognizer.RecognizeCompleted -= OnRecognizeCompleted;
+				offlineSpeechRecognizer.SpeechRecognized -= OnSpeechRecognized;
+				offlineSpeechRecognizer?.Dispose();
+				offlineSpeechRecognizer = null;
+			}
+		}
 	}
 
 	[MemberNotNull(nameof(recognitionText), nameof(offlineSpeechRecognizer), nameof(speechToTextOptions))]
@@ -102,6 +110,7 @@ void Initialize(SpeechToTextOptions options)
 		speechToTextOptions = options;
 		recognitionText = string.Empty;
 		offlineSpeechRecognizer = new SpeechRecognitionEngine(options.Culture);
+		offlineSpeechRecognizer.LoadGrammarAsync(new DictationGrammar());
 	}
 
 	void OfflineSpeechRecognizer_StateChanged(object? sender, AudioStateChangedEventArgs e)

src/CommunityToolkit.Maui.Core/Essentials/SpeechToText/SpeechToTextImplementation.windows.cs

@@ -1,6 +1,5 @@
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Globalization;
-using System.Speech.Recognition;
 using Microsoft.Maui.ApplicationModel;
 using Windows.Globalization;
 using Windows.Media.SpeechRecognition;
@@ -35,8 +34,6 @@ public SpeechToTextState CurrentState
 	public async ValueTask DisposeAsync()
 	{
 		await StopRecording(CancellationToken.None);
-		speechRecognizer?.Dispose();
-		speechRecognizer = null;
 	}
 
 	async Task InternalStartListeningAsync(SpeechToTextOptions options, CancellationToken cancellationToken)
@@ -48,7 +45,10 @@ async Task InternalStartListeningAsync(SpeechToTextOptions options, Cancellation
 		speechRecognizer.ContinuousRecognitionSession.Completed += OnCompleted;
 		try
 		{
-			await speechRecognizer.ContinuousRecognitionSession.StartAsync().AsTask(cancellationToken);
+			if (speechRecognizer.State == SpeechRecognizerState.Idle)
+			{
+				await speechRecognizer.ContinuousRecognitionSession.StartAsync().AsTask(cancellationToken);
+			}
 		}
 		catch (Exception ex) when ((uint)ex.HResult is privacyStatementDeclinedCode)
 		{
@@ -88,12 +88,8 @@ async Task StopRecording(CancellationToken cancellationToken)
 	{
 		try
 		{
-			if (speechRecognizer is not null)
+			if (speechRecognizer is not null && speechRecognizer.State != SpeechRecognizerState.Idle)
 			{
-				speechRecognizer.StateChanged -= SpeechRecognizer_StateChanged;
-				speechRecognizer.ContinuousRecognitionSession.ResultGenerated -= ResultGenerated;
-				speechRecognizer.ContinuousRecognitionSession.Completed -= OnCompleted;
-
 				cancellationToken.ThrowIfCancellationRequested();
 				await speechRecognizer.ContinuousRecognitionSession.StopAsync().AsTask(cancellationToken);
 			}
@@ -102,6 +98,17 @@ async Task StopRecording(CancellationToken cancellationToken)
 		{
 			// ignored. Recording may be already stopped
 		}
+		finally
+		{
+			if (speechRecognizer is not null)
+			{
+				speechRecognizer.StateChanged -= SpeechRecognizer_StateChanged;
+				speechRecognizer.ContinuousRecognitionSession.ResultGenerated -= ResultGenerated;
+				speechRecognizer.ContinuousRecognitionSession.Completed -= OnCompleted;
+				speechRecognizer?.Dispose();
+				speechRecognizer = null;
+			}
+		}
 	}
 
 	[MemberNotNull(nameof(recognitionText), nameof(speechRecognizer), nameof(speechToTextOptions))]