问题:

In my app, I call TextToSpeech.getLanguage() well after instantiating TextToSpeech (~800ms according to LogCat), yet it sometimes (not always) return null, despite the language set properly in the system's TextToSpeech settings:

System Settings > Language & input > 
  Text-to-speech output > Google Text-to-speech > English (United Kingdom)

This only happens in Jelly Bean (Android 4.1.1). It doesn't happen in Android 2.2.

Is this a known Android bug? Or am I doing something wrong?

I instantiate, BTW, TextToSpeech in my app's main activity with:

new TextToSpeech(this, this);

And both instantiation and the call to TextToSpeech.getLanguage() are made in the same thread (thus order of calls is guaranteed).

回答1:

You have to call getLanguage () in onInit (), sometimes it takes a few second for onInit () to be called.

回答2:

I also discovered this bug today on an Asus TF700T running Android 4.1.1. I tried to resolve the issue by calling getLanguage() again as Eternal Learner suggested in a comment, but it still returns null no matter how many times I call it.

The easiest workaround for me was to abandon the current broken instance of TextToSpeech and create a new instance. The second instance seems to work reliably.