安卓 "speak failed: not bound to tts engine"

Question

我的 android 应用程序具有文本朗读功能，并且不止一个 Activity 使用此功能。因此创建了一个静态帮助类来简化此操作。

import java.util.Locale;

import android.content.Context;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.util.Log;

public class TextToSpeechController implements OnInitListener {

    private static final String TAG = "TextToSpeechController";
    private TextToSpeech myTTS;
    private String textToSpeak;
    private Context context;

    private static TextToSpeechController singleton;

    public static TextToSpeechController getInstance(Context ctx) {
        if (singleton == null)
            singleton = new TextToSpeechController(ctx);
        return singleton;
    }

    private TextToSpeechController(Context ctx) {
        context = ctx;
    }

    public void speak(String text) {
        textToSpeak = text;

        if (myTTS == null) {
            // currently can't change Locale until speech ends
            try {
                // Initialize text-to-speech. This is an asynchronous operation.
                // The OnInitListener (second argument) is called after
                // initialization completes.
                myTTS = new TextToSpeech(context, this);

            } catch (Exception e) {             
                e.printStackTrace();
            }
        }

        sayText();

    }

    public void onInit(int initStatus) {
        if (initStatus == TextToSpeech.SUCCESS) {
            if (myTTS.isLanguageAvailable(Locale.UK) == TextToSpeech.LANG_AVAILABLE)
                myTTS.setLanguage(Locale.UK);
        }

        // status can be either TextToSpeech.SUCCESS or TextToSpeech.ERROR.
        if (initStatus == TextToSpeech.SUCCESS) {
            int result = myTTS.setLanguage(Locale.UK);
            if (result == TextToSpeech.LANG_MISSING_DATA
                    || result == TextToSpeech.LANG_NOT_SUPPORTED) {
                Log.e(TAG, "TTS missing or not supported (" + result + ")");
                // Language data is missing or the language is not supported.
                // showError(R.string.tts_lang_not_available);

            } else {
                // Initialization failed.
                Log.e(TAG, "Error occured");
            }

        }
    }

    private void sayText() {
        // ask TTs to say the text
        myTTS.speak(this.textToSpeak, TextToSpeech.QUEUE_FLUSH,     null);
    }

    public void stopTTS() {
        if (myTTS != null) {
            myTTS.shutdown();
            myTTS.stop();
            myTTS = null;
        }
    }

}

我正在像这样使用这个助手类。

TextToSpeechController.getInstance(this).speak(readableMessage);

但有时我会在 LogCat 上看到类似以下行的错误。

"speak:failed not bound to tts engine"

没有抛出异常，但 TTS 没有读取任何内容。我意识到如果我从 BroadcastReceiver 触发 Activity ，我会收到此错误。否则，如果从应用程序代码手动打开 Activity 没有问题。

这是广播接收器代码

private final BroadcastReceiver mHandleMessageReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String newMessage = intent.getExtras().getString(EXTRA_MESSAGE);            
        String readableMessage = intent.getExtras().getString(READABLE_MESSAGE);    

        Bundle b = new Bundle();
        b.putString(EXTRA_MESSAGE, newMessage);
        b.putString(READABLE_MESSAGE, readableMessage);
        Intent newIntent = new Intent("android.intent.action.MAIN");
        newIntent.setClass(context, Speak.class);
        newIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        newIntent.putExtra("MessageReceived", b);
        newIntent.putExtra("CallType", CallType.NOTIFICATION);
        context.startActivity(newIntent);           
    }
};

Answer 1

您的代码没有等待 TextToSpeech 类的构造函数的异步返回。你甚至有一条评论说它是异步的。为什么它总是在接收器中失败，但不是 Activity 我不确定 - 除了可能作为前台任务的 Activity 具有更高的优先级并且它恰好在您调用 sayText 之前完成。

如果它必须新建一个新的 TTS 对象，您需要等待调用 sayText 直到 init 调用返回。