在以下场景中观察到 TTS 初始化错误，该错误过于随机。
TTS 引擎已安装，语音集已存在，并且可以从辅助功能选项中播放示例 tts。
TTS 初始化在先前初始化和播放的同一设备上随机失败。
在不同的设备（一加、华硕、三星）和各种 Android 操作系统版本中观察到此问题。
代码片段：
公共类 TTSHandler 实现 OnInitListener {
public EPUBReader context;
private TextToSpeech tts;
private HashMap<String, String> ttsMap;
private boolean isTtsPlaying = false,shouldResume = false,initialised = false,
ttsModeEnabled = false;
private String textToRead;
private GoogleVersionPreferences mSharedPreferences;
private AudioManager mAudioManager;
@SuppressWarnings("deprecation")
public TTSHandler(EPUBReader context){
this.context = context;
tts = new TextToSpeech(context,this);
}
@Override
public void onInit(int status) {
Log.d("TTS", "onInit called");
if(status == TextToSpeech.SUCCESS){
initialised = true;
Log.d("TTS", "initialised success: status = "+status);
initTTSComponents();
}else{
initialised = false;
Log.d("TTS", " initialised failed: status ="+status);
}
}
/**
* called form JavascriptInterface
* @param text is the sentence to be read
*/
public void readText(String text){
if(text!=null){
textToRead = text;
}
ttsMap = new HashMap<String, String>();
ttsMap.put(TextToSpeech.Engine.KEY_PARAM_UTTERANCE_ID, textToRead);
//for Next/Prev
isTtsPlaying = true;
context.runOnUiThread(new Runnable(){
@Override
public void run() {
context.toggleTtsIcons();
}
});
tts.speak(textToRead,0, ttsMap);
}
/**
* called to play,pause or resume tts play.
*/
public void playPauseReading(){
context.lockOrientationChange();
AudioManager audio = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
int volume = audio.getStreamVolume(AudioManager.STREAM_MUSIC);
if(isTtsPlaying){
isTtsPlaying = false;
shouldResume = true;
tts.stop();
}else{
isTtsPlaying = true;
if(shouldResume){
shouldResume = false;
requestAudioFocusForTTS();
JavaScriptInterface.loadJavascript("javascript:resumeUsingTts()", context.getEPUBReaderFragment().getWebview());
}else{
requestAudioFocusForTTS();
if(volume <= 1){
Toast.makeText(context,context.getResources().getString(R.string.tts_volume_alert), 300).show();
}
int dir = mSharedPreferences.getEpubNavigationSetting(context.bookId);
JavaScriptInterface.loadJavascript("javascript:playFromRange("+dir+")", context.getEPUBReaderFragment().getWebview());
}
}
context.toggleTtsIcons();
}
/**
* called to stop playing tts
* highlight will be removed and we will hide the tts controls
*/
public void stopReading(){
if(tts !=null && ttsModeEnabled){
isTtsPlaying = false;
shouldResume = false;
ttsModeEnabled = false;
tts.stop();
Toast.makeText(context,context.getResources().getString(R.string.tts_stop) , 300).show();
JavaScriptInterface.loadJavascript("javascript:stopUsingTts()",
context.getEPUBReaderFragment().getWebview());
abandonAudioFocus();
context.runOnUiThread(new Runnable(){
@Override
public void run() {
context.toggleControlPanel(false);
context.unlockOrientationChange();
context.invalidateOptionsMenu();
}
});
}
}
/**
* To check the whether tts is playing or not
* @return
*/
public boolean isReading(){
if(tts.isSpeaking()){
return true;
}
return false;
}
/**
* called from javascriptInterface at the end of a chapter
*
*/
public void stopReadingOnEndOfChapter(){
Log.d("TTS", "stopReadingOnEndOfChapter");
shouldResume = false;
isTtsPlaying = false;
ttsModeEnabled = false;
abandonAudioFocus();
context.runOnUiThread(new Runnable(){
@Override
public void run() {
context.toggleControlPanel(false);
context.unlockOrientationChange();
context.invalidateOptionsMenu();
Toast.makeText(context,context.getResources().getString(R.string.end_of_chapter) , 300).show();
}});
}
/**
* called from javascriptInterface to disable tts mode when the chapter doesnt have any text content.
*/
public void stopOnNoContent(){
Toast.makeText(context,context.getResources().getString(R.string.tts_no_content) , 300).show();
shouldResume = false;
isTtsPlaying = false;
ttsModeEnabled = false;
abandonAudioFocus();
context.runOnUiThread(new Runnable(){
@Override
public void run() {
context.toggleControlPanel(false);
context.unlockOrientationChange();
context.invalidateOptionsMenu();
}});
}
/**
* called from javascript to stop tts while user taps on links
*/
public void stopTtsOnLinks(){
if(isReading() || shouldResume)
Toast.makeText(context,context.getResources().getString(R.string.tts_stop) , 300).show();
shouldResume = false;
isTtsPlaying = false;
ttsModeEnabled = false;
tts.stop();
context.toggleControlPanel(false);
context.unlockOrientationChange();
abandonAudioFocus();
}
/**
* Will release the resources used by the TTS engine
*/
public void shutDownTTS(){
if(tts !=null){
tts.shutdown();
}
}
/**
* called from EPUBReader to set the speech rate
* @param speechRate
*/
public void setSpeechRate(int value){
switch(value){
case 0:
tts.setSpeechRate((float)0.1);
break;
case 1:
tts.setSpeechRate((float)0.5);
break;
case 2:
tts.setSpeechRate((float)1);
break;
case 3:
tts.setSpeechRate((float)1.5);
break;
case 4:
tts.setSpeechRate((float)2);
break;
}
}
/**
* called form EPUBReader to start playing the next line
*/
public void playNext(){
isTtsPlaying = false;
tts.stop();
JavaScriptInterface.loadJavascript("javascript:readNext()",context.getEPUBReaderFragment().getWebview());
}
/**
* called form EPUBReader to start playing the previous line
*/
public void playPrevious(){
isTtsPlaying = false;
tts.stop();
JavaScriptInterface.loadJavascript("javascript:playPrevious()",context.getEPUBReaderFragment().getWebview());
}
/**
* if TTS engine is initialised successfully,
* we will set the listener and other components.
*/
private void initTTSComponents(){
mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
tts.setSpeechRate(1);
mSharedPreferences = GoogleVersionPreferences.getGoogleAppVersion(context);
tts.setOnUtteranceProgressListener(new UtteranceProgressListener() {
@Override
public void onStart(String utteranceId) {
Log.d("TTS", "onStart:"+utteranceId);
}
@Override
public void onError(String utteranceId) {
Log.d("TTS", "onError ID:"+utteranceId);
}
@Override
public void onDone(String utteranceId) {
Log.d("BUG", "onDone, isTtsPlaying:"+isTtsPlaying);
if(isTtsPlaying){
JavaScriptInterface.loadJavascript("javascript:readNext();",
((EPUBReader) context).getEPUBReaderFragment().getWebview());
}
}
});
}
/**
* Requests audio focus so that when TTS starts
* other audio apps will be paused/ducked as per the app.
*/
private void requestAudioFocusForTTS(){
mAudioManager.requestAudioFocus(null,AudioManager.STREAM_MUSIC , AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE);
}
/**
*Will abandon the received audio Focus so that the
*previous app can attain it.
*/
private void abandonAudioFocus(){
mAudioManager.abandonAudioFocus(null);
}
/**
* getters and setters
* @param value
*/
public void setisTtsPlaying(boolean value){
isTtsPlaying = value;
}
public boolean isTtsPlaying(){
return isTtsPlaying;
}
public void setshouldResume(boolean value){
shouldResume = value;
}
public boolean shouldResume(){
return shouldResume;
}
public boolean isTtsInitialised(){
return initialised;
}
public boolean ttsModeEnabled(){
return ttsModeEnabled;
}
public void setttsModeEnabled(boolean value){
ttsModeEnabled = value;
}
}
注意：收集的日志：
对于三星设备（TabS 10.5 操作系统：5.0.2）：
E/SamsungTTS(20259): onLoadLanguage() - SamsungTTS 尚未准备好。
对于一加一（操作系统：6.0.1）：
08-08 18：54：53.112：W/TextToSpeech（22946）：停止失败：TTS 引擎连接未完全建立
08-08 18：56：15.869：I / TextToSpeech（22946）：成功绑定到com.google.android.tts
08-08 18：56：16.060：I / TextToSpeech（22946）：连接到ComponentInfo {com.google.android.tts/com.google.android.tts.service.GoogleTTSService}
