How do I add speech to text API in android studio?

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I really have to implement a Speech-to-text API in android studio. Help me please.
I searched some codes but it requires MS visual studio.

What I have tried:

i tried this code;

private void startSpeechToText() {
        Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech-to-text input");
        startActivityForResult(intent, REQUEST_CODE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_CODE && resultCode == RESULT_OK)
        {
            ArrayList<String> result = data
                    .getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
            String text = result.get(0);
            itemName.setText(text);

        }
        super.onActivityResult(requestCode, resultCode, data);
    }

private final int REQUEST_CODE = 1234;