## Set up the backend

Run `amplify add predictions`, then use the following answers:

```console
? Please select from one of the categories below
  `Convert`
? What would you like to convert? (Use arrow keys)
  `Generate speech audio from text`
? Provide a friendly name for your resource
  `speechGenerator`
? What is the source language? (Use arrow keys)
  `US English`
? Select a speaker (Use arrow keys)
  `Joanna - Female`
? Who should have access? (Use arrow keys)
  `Auth and Guest users`
```

Run `amplify push` to create the resources in the cloud.

## Working with the API

<BlockSwitcher>
<Block name="Java">

Open `MainActivity.java` and add the following code:

```java
private final MediaPlayer mp = new MediaPlayer();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Amplify.Predictions.convertTextToSpeech(
            "I like to eat spaghetti",
            result -> playAudio(result.getAudioData()),
            error -> Log.e("MyAmplifyApp", "Conversion failed", error)
    );
}

private void playAudio(InputStream data) {
    File mp3File = new File(getCacheDir(), "audio.mp3");

    try (OutputStream out = new FileOutputStream(mp3File)) {
        byte[] buffer = new byte[8 * 1_024];
        int bytesRead;
        while ((bytesRead = data.read(buffer)) != -1) {
            out.write(buffer, 0, bytesRead);
        }
        mp.reset();
        mp.setOnPreparedListener(MediaPlayer::start);
        mp.setDataSource(new FileInputStream(mp3File).getFD());
        mp.prepareAsync();
    } catch (IOException error) {
        Log.e("MyAmplifyApp", "Error writing audio file", error);
    }
}
```

</Block>
<Block name="Kotlin - Callbacks">

Open `MainActivity.kt` and add the following code:

```kotlin
private val mp = MediaPlayer()

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    convertTextToSpeech()
}

private fun convertTextToSpeech() {
    Amplify.Predictions.convertTextToSpeech("I like to eat spaghetti!",
        { playAudio(it.audioData) },
        { Log.e("MyAmplifyApp", "Failed to convert text to speech", it) }
    )
}

private fun playAudio(data: InputStream) {
    val mp3File = File(cacheDir, "audio.mp3")
    try {
        FileOutputStream(mp3File).use { out ->
            val buffer = ByteArray(8 * 1024)
            var bytesRead: Int
            while (data.read(buffer).also { bytesRead = it } != -1) {
                out.write(buffer, 0, bytesRead)
            }
            mp.reset()
            mp.setOnPreparedListener { obj: MediaPlayer -> obj.start() }
            mp.setDataSource(FileInputStream(mp3File).fd)
            mp.prepareAsync()
        }
    } catch (error: IOException) {
        Log.e("MyAmplifyApp", "Error writing audio file.")
    }
}
```

</Block>
<Block name="Kotlin - Coroutines">

Open `MainActivity.kt` and add the following code:

```kotlin
private val mp = MediaPlayer()

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    convertTextToSpeech()
}

private fun convertTextToSpeech() = activityScope.launch {
    val text = "I like to eat spaghetti!"
    try {
        val result = Amplify.Predictions.convertTextToSpeech(text)
        playAudio(result.audioData)
    } catch (error: PredictionsException) {
        Log.e("MyAmplifyApp", "Failed to convert text to speech", error)
    }
}

private fun playAudio(data: InputStream) {
    val mp3File = File(cacheDir, "audio.mp3")
    try {
        FileOutputStream(mp3File).use { out ->
            val buffer = ByteArray(8 * 1024)
            var bytesRead: Int
            while (data.read(buffer).also { bytesRead = it } != -1) {
                out.write(buffer, 0, bytesRead)
            }
            mp.reset()
            mp.setOnPreparedListener { obj: MediaPlayer -> obj.start() }
            mp.setDataSource(FileInputStream(mp3File).fd)
            mp.prepareAsync()
        }
    } catch (error: IOException) {
        Log.e("MyAmplifyApp", "Error writing audio file.")
    }
}
```

</Block>
<Block name="RxJava">

Open `MainActivity.java` and add the following code:

```java
private final MediaPlayer mp = new MediaPlayer();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    RxAmplify.Predictions.convertTextToSpeech("I like to eat spaghetti")
            .subscribe(
                result -> playAudio(result.getAudioData()),
                error -> Log.e("MyAmplifyApp", "Conversion failed", error)
            );
}

private void playAudio(InputStream data) {
    File mp3File = new File(getCacheDir(), "audio.mp3");

    try (OutputStream out = new FileOutputStream(mp3File)) {
        byte[] buffer = new byte[8 * 1_024];
        int bytesRead;
        while ((bytesRead = data.read(buffer)) != -1) {
            out.write(buffer, 0, bytesRead);
        }
        mp.reset();
        mp.setOnPreparedListener(MediaPlayer::start);
        mp.setDataSource(new FileInputStream(mp3File).getFD());
        mp.prepareAsync();
    } catch (IOException error) {
        Log.e("MyAmplifyApp", "Error writing audio file", error);
    }
}
```

</Block>
</BlockSwitcher>

This example works on all supported versions of Android. Android API 23 added support for [`MediaDataSource`](https://developer.android.com/reference/android/media/MediaDataSource), which allows for `InputStream` from Amplify to be read directly without writing to a file.

As a result of running this code, you will hear audio of the text being emitted from your device.