SpeechSynthesizer

class SpeechSynthesizer : Closeable

// 1. Create a SpeechSynthesizer with desired options.
val options: SpeechSynthesizerOptions =
    speechSynthesizerOptions(Locale.US) {
        // Optionally configure a background executor
        // setExecutor(myExecutor)
        // Optionally fail instead of substituting a voice that is not installed
        // setVoiceFallbackEnabled(false)
    }
val speechSynthesizer: SpeechSynthesizer = SpeechSynthesis.getClient(options)

// 2. Find a supported voice and check its status.
lifecycleScope.launch {
    try {
        // Defaults to the options locale. Pass one to switch language:
        //     speechSynthesizer.getSupportedVoices(Locale.FRANCE)
        val supportedVoices: List<VoiceInfo> = speechSynthesizer.getSupportedVoices()
        val voiceToUse: VoiceInfo? =
            supportedVoices.firstOrNull { it.gender == VoiceInfo.Gender.FEMALE }

        if (voiceToUse != null) {
            val status: Int = speechSynthesizer.checkStatus(voiceToUse)
            if (status == FeatureStatus.DOWNLOADABLE) {
                // 3. If needed, download the voice model.
                speechSynthesizer.download(voiceToUse).collect { downloadStatus ->
                    when (downloadStatus) {
                        is DownloadStatus.DownloadCompleted -> {
                            // Model is ready, start synthesis.
                            startMySynthesis(speechSynthesizer, voiceToUse)
                        }
                        is DownloadStatus.DownloadFailed -> {
                            // Handle download failure.
                        }
                        is DownloadStatus.DownloadProgress -> {
                            // Handle download progress.
                        }
                        else -> {}
                    }
                }
            } else if (status == FeatureStatus.AVAILABLE) {
                // Model is ready, start synthesis.
                startMySynthesis(speechSynthesizer, voiceToUse)
            } else {
                // Handle other statuses like DOWNLOADING or UNAVAILABLE.
            }
        }
    } finally {
        // 5. Release resources. Closing outside the coroutine would tear down the client
        //    while the work above is still in flight.
        speechSynthesizer.close()
    }
}

// 4. Define your synthesis logic.
suspend fun startMySynthesis(synthesizer: SpeechSynthesizer, voice: VoiceInfo) {
  // Create a request and collect the responses.
  val request = SpeechSynthesizerRequest(
      input = SpeechSynthesizerRequest.Input.Text("Hello, world!", voice),
      audioAttributes = AudioAttributes.Builder()
          .setUsage(AudioAttributes.USAGE_MEDIA)
          .setContentType(AudioAttributes.CONTENT_TYPE_SPEECH)
          .build()
  )
  synthesizer.synthesize(request).collect { response ->
      // Process the responses.
      when (response) {
          is SpeechSynthesizerResponse.StatusUpdate -> {
              when (response.status) {
                  SpeechSynthesizerResponse.Status.START -> { /* Started playing */}
                  SpeechSynthesizerResponse.Status.DONE -> { /* Playback finished */}
                  else -> {}
              }
          }
          is SpeechSynthesizerResponse.AudioAvailable -> {
              // Handle a chunk of synthesized audio
          }
          is SpeechSynthesizerResponse.Error -> {
              // Handle synthesis error. With setVoiceFallbackEnabled(false), a voice that
              // is not installed arrives here as ERROR_NOT_INSTALLED_YET.
          }
      }
  }
}