Android TextToSpeech（TTS）庫允許您將文本轉換為語音。要處理音頻文件，您需要執行以下步驟：

1. 添加依賴項： 在Android項目的build.gradle文件中，添加TextToSpeech庫的依賴項：

dependencies {
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.google.android.gms:play-services-tts:17.0.0'
}

2. 初始化TextToSpeech對象： 在您的Activity或Fragment中，初始化TextToSpeech對象并設置語言。

import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;

public class MainActivity extends AppCompatActivity implements OnInitListener {

    private TextToSpeech tts;

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

        tts = new TextToSpeech(this, this);
    }

    @Override
    public void onInit(int status) {
        if (status == TextToSpeech.SUCCESS) {
            int language = TextToSpeech.LANG_ENGLISH; // 設置語言，例如英語
            tts.setLanguage(language);
        } else {
            Log.e("TextToSpeech", "Initialization failed");
        }
    }
}

3. 生成語音： 使用TextToSpeech類的synthesizeToFile()方法將文本轉換為音頻文件。

import android.os.AsyncTask;
import android.os.Environment;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class GenerateAudioTask extends AsyncTask<String, Void, Void> {

    private static final String DIRECTORY_NAME = "TTS_AUDIO";
    private static final String FILE_EXTENSION = ".mp3";

    @Override
    protected Void doInBackground(String... params) {
        String text = params[0];
        String filePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + DIRECTORY_NAME;
        File directory = new File(filePath);

        if (!directory.exists()) {
            directory.mkdirs();
        }

        String fileName = "output_" + System.currentTimeMillis() + FILE_EXTENSION;
        File audioFile = new File(filePath, fileName);

        try {
            tts.synthesizeToFile(text, TextToSpeech.QUEUE_FLUSH, audioFile.getAbsolutePath());
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }
}

4. 播放音頻文件： 使用MediaPlayer類播放生成的音頻文件。

import android.media.MediaPlayer;

public class PlayAudioActivity extends AppCompatActivity {

    private MediaPlayer mediaPlayer;

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

        String filePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/TTS_AUDIO/output_1633027800000.mp3";
        mediaPlayer = new MediaPlayer();

        try {
            mediaPlayer.setDataSource(filePath);
            mediaPlayer.prepare();
            mediaPlayer.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mediaPlayer != null) {
            mediaPlayer.release();
            mediaPlayer = null;
        }
    }
}

注意：在Android 6.0（API級別23）及更高版本中，需要在運行時請求存儲權限。確保在AndroidManifest.xml文件中添加以下權限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

并在運行時請求權限。