android.speech.tts.TextToSpeech.setLanguage(java.util.Locale)' on a null object reference

Question

My app crashes and in logcat I find the error

android.speech.tts.TextToSpeech.setLanguage(java.util.Locale)' on a null object reference

Here is my class :

public class cl_txt2speech {

    TextToSpeech txt2speech;
    Activity context;

    String txt2speech_current_language = "" ;
    boolean txt2speech_available = false ;

    //@Override
    protected void onCreate(Bundle savedInstanceState) {

        txt2speech = new TextToSpeech(context.getApplicationContext(), new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int status) {
                if (status != TextToSpeech.ERROR) {
                    txt2speech_available = true ;
                }
            }
        });
    }

    void txt2speech_change_language( String lang )
    {
        if( lang=="fr" )
        {
            txt2speech.setLanguage(Locale.FRANCE);
        }
        else if( lang=="en" )
        {
            txt2speech.setLanguage(Locale.UK);
        }
        else if( lang=="es" )
        {
            Locale locSpanish = new Locale("spa", "MEX");
            txt2speech.setLanguage(locSpanish);
        }
        txt2speech_current_language = lang ;
    }

    void txt2speech_speak( String lang , String txt )
    {
        if( lang != txt2speech_current_language ){ txt2speech_change_language( lang ); }
        txt2speech.speak(txt, TextToSpeech.QUEUE_FLUSH, null);
    }
}

and here is how I use it

cl_txt2speech txt2speech = new cl_txt2speech();
txt2speech.txt2speech_speak( "fr" , "test, 1 2 3" );

I don't understand what is the problem, I defined TextToSpeech txt2speech ; at the beginning.

update 1 : I did add some System.out.println() to trace what is happening, and it seems that the code in onCreate is never executed. So the problem must come from how I use my class.

update 2 :

I ended up moving everything to my fullscreenActivity.java file instead of using a class, to see what happens.

public class FullscreenActivity extends AppCompatActivity implements
        TextToSpeech.OnInitListener{
...
public TextToSpeech txt2speech;
...
@Override
protected void onCreate(Bundle savedInstanceState) {
    ...
    txt2speech = new TextToSpeech(this, this);
    ...
}

@Override
public void onInit(int status) {
    System.out.println( "--------------- onInit() -------------" );
    if (status != TextToSpeech.ERROR) {
        txt2speech_available = true;
    }
}

and onInit is never fired here neither...

Also, when calling txt2speech.getDefaultLanguage() I have the error "getDefaultLanguage failed: not bound to TTS engine"

Answer 1

You commented out the @Override annotation of the method onCreate() that way it's just a meaningless method which never gets called.

Edit: I just saw your class doesn't extend Activity, that way you can't override the method IIRC. Try refactoring that piece of code into the constructor of your class.

Answer 2

The txt2speech object never has been initialized. Edit your code like below and then you can create a object of cl_txt2speech class in some activity :

public class cl_txt2speech {

    TextToSpeech txt2speech;

    String txt2speech_current_language = "" ;
    boolean txt2speech_available = false ;

    public cl_txt2speech(Context context) {

        txt2speech = new TextToSpeech(context.getApplicationContext(), new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int status) {
                if (status != TextToSpeech.ERROR) {
                    txt2speech_available = true ;
                }
            }
        });
    }

    void txt2speech_change_language( String lang )
    {
        if( lang=="fr" )
        {
            txt2speech.setLanguage(Locale.FRANCE);
        }
        else if( lang=="en" )
        {
            txt2speech.setLanguage(Locale.UK);
        }
        else if( lang=="es" )
        {
            Locale locSpanish = new Locale("spa", "MEX");
            txt2speech.setLanguage(locSpanish);
        }
        txt2speech_current_language = lang ;
    }

    void txt2speech_speak( String lang , String txt )
    {
        if( lang != txt2speech_current_language ){ txt2speech_change_language( lang ); }
        txt2speech.speak(txt, TextToSpeech.QUEUE_FLUSH, null);
    }
}

And here is how to use :

cl_txt2speech txt2speech = new cl_txt2speech(this);
txt2speech.txt2speech_speak( "fr" , "test, 1 2 3" );