Question

I put speech function into a new class called voiceAssistants, however, when i start it, it always give me an null pointer exception error.

voice Assistants:

public class VoiceAssistants {
    private static final int VOICE_RECOGNITION_REQUEST_CODE = 1234;
    private static VoiceActivityHelper voiceAssistants;
    public VoiceAssistants(){
        voiceAssistants = new VoiceActivityHelper();
    }
    /**
     * Start voice input
     */
    public void starVoiceAssistants(){
        this.voiceAssistants.startVoiceRecognitionActivity();
    }

    private static class VoiceActivityHelper extends Activity {

        private static ArrayList<String> matches;

        public ArrayList<String> getResultSet(){
            return matches;
        }

        private void startVoiceRecognitionActivity() {
            Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, String.format(
                "%s_%s", Locale.getDefault().getLanguage(), Locale
                        .getDefault().getCountry()));
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT,
                "Speech recognition demo");
                        //error happen here!!!
            startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
        }
    }
}

But when I put it into normal activity that generated by new project, it won’t tall any error.
log infos:

E/AndroidRuntime(22769): java.lang.NullPointerException
E/AndroidRuntime(22769):
at android.app.Activity.startActivityForResult(Activity.java:2827)
E/AndroidRuntime(22769):    
at panda.com.db.VoiceAssistants$VoiceActivityHelper.startVoiceRecognitionActivity(VoiceAssistants.java:56)
E/AndroidRuntime(22769):    
at panda.com.db.VoiceAssistants$VoiceActivityHelper.access$1(VoiceAssistants.java:47)
E/AndroidRuntime(22769):    
at panda.com.db.VoiceAssistants.starVoiceAssistants(VoiceAssistants.java:24)

plz help, thank you!!

Answer 1

You’re calling startActivityForResult() but this isn’t an Activity. Your Activity is a private inner class that no one else has access to.