如何在Android应用中正确地使用Text-to-Speech (TTS)功能来播放语音?

在Android应用中使用Text-to-Speech (TTS) 功能来播放语音通常涉及以下几个步骤：

1. **添加权限**：在`AndroidManifest.xml`文件中添加`<uses-permission>`标签，允许应用程序访问设备的TTS服务：

   <uses-permission android:name="android.permission.RECORD_AUDIO" />
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-feature android:name="android.speech.tts" android:required="true" />

2. **初始化TTS引擎**：在你的Activity或Fragment中，创建一个`TextToSpeech`对象并初始化它，例如：

   private TextToSpeech textToSpeech;
   ...
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       textToSpeech = new TextToSpeech(this, new TextToSpeech.OnInitListener() {
           @Override
           public void onInit(int status) {
               if (status == TextToSpeech.SUCCESS) {
                   int lang = textToSpeech.setLanguage(Locale.getDefault()); // 设置语言
                   if (lang != TextToSpeech.LANG_MISSING_DATA && lang != TextToSpeech.LANG_NOT_SUPPORTED) {
                       speak("Hello, world!"); // 开始播放语音
                   }
               } else {
                   Toast.makeText(MainActivity.this, "TTS initialization failed", Toast.LENGTH_SHORT).show();
               }
           }
       });
   }

   private void speak(String text) {
       if (textToSpeech != null) {
           speechUtterance = new SpeechUtterance(text);
           speechUtterance.setVoice(textToSpeech.getVoice());
           try {
               textToSpeech.speak(speechUtterance, TextToSpeech.QUEUE_ADD, null);
           } catch (Exception e) {
               Log.e(TAG, "Error speaking:", e);
           }
       }
   }

3. **释放资源**：当不再需要TTS服务时，记得关闭它：

   @Override
   protected void onDestroy() {
       if (textToSpeech != null) {
           textToSpeech.stop();
           textToSpeech.shutdown();
       }
       super.onDestroy();
   }