# .NET MAUI SpeechToTextButton Custom Recognizer

The .NET MAUI SpeechToTextButton allows you to use a custom speech recognizer by implementing the `IRadSpeechRecognizer` interface. This enables you to integrate third-party speech recognition services or customize the behavior of the speech recognition process.

## Implementation Steps

Follow these steps to implement a custom speech recognizer:

**1.** Define the `SpeechToTextButton` in XAML:

```XAML
<Grid ColumnDefinitions="*, Auto"
	  RowDefinitions="Auto">
	<Editor x:Name="editor"
			AutoSize="TextChanges" />
	<telerik:RadSpeechToTextButton x:Name="speechToTextButton"
								   SpeechRecognized="OnSpeechRecognized"
								   Grid.Column="1"
								   VerticalOptions="Start" />
</Grid>
```

**2.** Add the `telerik` namespace:

```XAML
xmlns:telerik="http://schemas.telerik.com/2022/xaml/maui"
```

**3.** Create a class `MyCustomSpeechRecognizer` that implements the `IRadSpeechRecognizer` interface:

```C#
public class MyCustomSpeechRecognizer : IRadSpeechRecognizer
{
	private const string MockText = "This is a mocked speech recognizer response for testing purposes and it will not really do a voice transcription in your system.";
	
	private SpeechRecognizerState state;
	private int reportingSessionId;

	public SpeechRecognizerState State
	{
		get => this.state;
		private set
		{
			if (this.state != value)
			{
				this.state = value;
				this.StateChanged?.Invoke(this, EventArgs.Empty);
			}
		}
	}

	public event EventHandler StateChanged;
	public event EventHandler<SpeechRecognizerErrorOccurredEventArgs> ErrorOccurred;
	public event EventHandler<SpeechRecognizerSpeechRecognizedEventArgs> SpeechRecognized;

	public Task Init(SpeechRecognizerInitializationContext context)
	{
		this.State = SpeechRecognizerState.Ready;
		this.reportingSessionId++;
		return Task.CompletedTask;
	}

	public Task StartListening()
	{
		this.State = SpeechRecognizerState.StartingListening;
		this.reportingSessionId++;
		int localSessionId = this.reportingSessionId;

		Task.Run(() =>
		{
			this.State = SpeechRecognizerState.Listening;
			int i = 0;
			string[] words = MockText.Split(' ', StringSplitOptions.RemoveEmptyEntries);
			string fullText = string.Empty;

			while (true)
			{
				string word = words[i % words.Length];
				fullText += $" {word}";
				i++;

				Thread.Sleep(333);

				if (localSessionId != this.reportingSessionId)
				{
					break;
				}

				this.SpeechRecognized?.Invoke(this, new SpeechRecognizerSpeechRecognizedEventArgs(fullText));
			}
		});

		return Task.CompletedTask;
	}

	public async Task StopListening()
	{
		this.State = SpeechRecognizerState.Ready;
		this.reportingSessionId++;
		await Task.Yield();
	}

	public Task Reset()
	{
		this.State = SpeechRecognizerState.NotInitialized;
		this.reportingSessionId++;
		return Task.CompletedTask;
	}

	public ValueTask DisposeAsync()
	{
		this.State = SpeechRecognizerState.Disposed;
		this.reportingSessionId++;
		return ValueTask.CompletedTask;
	}
}
```

**4.** Set the `SpeechRecognizerCreator` property of the `RadSpeechToTextButton` to an instance of your custom recognizer:

```C#
this.speechToTextButton.SpeechRecognizerCreator = () => new MyCustomSpeechRecognizer();
```

**5.** Handle the `SpeechRecognized` event to process the recognition results:

```C#
private void OnSpeechRecognized(object sender, Telerik.Maui.SpeechRecognizer.SpeechRecognizerSpeechRecognizedEventArgs e)
{
	this.editor.Text = e.FullText;
}
```

This is the result on Android:

![.NET MAUI SpeechToTextButton Custom Recognizer](https://www.telerik.com/maui-ui/documentation/assets/4254655770a072ea4c74aad158ad34fa/speechtotextbutton-custom-recognizer.gif)

> For a runnable example with the SpeechToTextButton Custom Recognizer scenario, see the [SDKBrowser Demo Application](https://www.telerik.com/maui-ui/documentation/demos-and-sample-apps/sdkbrowser-app) and go to the **SpeechToTextButton > Features** category.

## See Also

* [Set Visual States](https://www.telerik.com/maui-ui/documentation/controls/speechtotextbutton/visual-states)
* [Events](https://www.telerik.com/maui-ui/documentation/controls/speechtotextbutton/events)
* [Style the SpeechToTextButton](https://www.telerik.com/maui-ui/documentation/controls/speechtotextbutton/styling)