IssueTracker

According to documentation [1] of TextToSpeech.UtteranceProgressListener there are two onError functions, one added in API 21, one deprecated in API 21:

abstract void   onError(String utteranceId) -> This method was deprecated in API level 21. Use onError(java.lang.String, int) instead

void    onError(String utteranceId, int errorCode) -> Called when an error has occurred during processing. (Added in API 21)

However, after rigorous testing I have found out that the one added in API 21 is never being called when an error occurs, only the deprecated onError function is being called. Other developers have observed the same behavior [2], [3].

I have tried to track the behavior back to android.speech.tts.TextToSpeech and I think it is explainable that the added function is never being called, see line 2140 in android.speech.tts.TextToSpeech [4].

[1] https://developer.android.com/reference/android/speech/tts/UtteranceProgressListener
[2] https://stackoverflow.com/questions/55107074/utteranceprogresslistener-does-not-return-error-message
[3] https://stackoverflow.com/questions/55080063/android-texttospeech-behaves-irregular
[4] https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/speech/tts/TextToSpeech.java#2140

Android version tested: Various devices ranging from API 21 to API 28, all with minSdkVersion 21 and targetSdkVersion 28

To easier test all of this, below is code that has to be pasted into any Activity and can then be experienced:

```
package com.test.mytexttospeech

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.speech.tts.TextToSpeech
import android.speech.tts.UtteranceProgressListener
import android.util.Log
import java.util.*

class UtteranceProgressListenerActivity : AppCompatActivity() {

    var textToSpeech: TextToSpeech? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        speakUtterances()
    }

    /**
     * Initialize TextToSpeech and speak all utterances upon successful initialization
     */
    fun speakUtterances() {
        textToSpeech = TextToSpeech(this,
            TextToSpeech.OnInitListener { status ->
                if (status == TextToSpeech.SUCCESS) {
                    textToSpeech?.setOnUtteranceProgressListener(utteranceProgressListener)
                    listOfUtterances.forEach { utterance ->
                        textToSpeech?.language = utterance.locale
                        textToSpeech?.speak(utterance.text, TextToSpeech.QUEUE_ADD, null, utterance.text)
                    }
                } else {
                    Log.d("OnInitL.", "--- init Error: $status")
                }
            },
            "com.google.android.tts")
    }

    /**
     * UtteranceProgressListener for our TextToSpeech
     */
    val utteranceProgressListener = object : UtteranceProgressListener() {
        override fun onStart(utteranceId: String?) {
            Log.d("UtteranceP.L.", "--- onStart($utteranceId)")
        }

        override fun onDone(utteranceId: String?) {
            Log.d("UtteranceP.L.", "--- onDone($utteranceId)")
        }

        override fun onError(utteranceId: String?) {                    // <-- THIS IS CALLED WHEN AN ERROR OCCURS!
            Log.d("UtteranceP.L.", "--- onError($utteranceId)")
        }

        override fun onError(utteranceId: String?, errorCode: Int) {    // <-- THIS IS NEVER CALLED WHEN AN ERROR OCCURS!
            Log.d("UtteranceP.L.", "--- onError($utteranceId, $errorCode)")
            super.onError(utteranceId, errorCode)
        }
    }

    /**
     * Helper Class
     */
    data class Utterance(val text: String, val locale: Locale)

    /**
     * List of Utterances
     */
    val listOfUtterances = listOf(
        Utterance("Today is a nice day!", Locale.ENGLISH),
        Utterance("Today is a nice day in India!", Locale("en", "IN")),
        Utterance("Today is a nice day in Australia!", Locale("en", "AU")),
        Utterance("Today is a nice day in Great Britain!", Locale("en", "GB")),
        Utterance("Heute ist ein schöner Tag!", Locale.GERMAN),
        Utterance("Aujourd'hui est une belle journée en france!", Locale("fr", "FR")),
        Utterance("Aujourd'hui est une belle journée au canada!", Locale("fr", "CA")),
        Utterance("今天是美好的一天!", Locale.SIMPLIFIED_CHINESE),
        Utterance("اليوم يوم جميل", Locale("ar")),  // This is not supported at all, so an error is thrown
        Utterance("Sot është një ditë e bukur!", Locale("sq")),
        Utterance("Danas je lijep dan u crotiau!", Locale("hr")),
        Utterance("Сегодня хороший день!", Locale("ru", "RU"))
    )
}

```