Android Speech To Text Tutorial

Android comes with an inbuilt feature speech to text through which you can provide speech input to your app. With this you can add some of the cool features to your app like adding voice navigation(Helpful when you are targeting disabled people), filling a form with voice input etc.,

In the background how voice input works is, the speech input will be streamed to a server, on the server voice will be converted to text and finally text will be sent back to our app.

If you want to do the other way i.e converting text to speech, follow my previous tutorial Android Text to Speech

speech to text banner

I have created a simple app to demonstrate this tutorial. Below is the screenshot of the app which contains a simple button to invoke speech input and a TextView to display the converted speech text.

android speech to text

So let’s start by creating simple app.

Sample Application

1. Create a new project in Eclipse by going to File ⇒ New ⇒ Android Application Project and give required information.

2. Open strings.xml located under res ⇒ values and add below string values.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">Speech To Text</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
    <string name="speech_prompt">Say something&#8230;</string>
    <string name="speech_not_supported">Sorry! Your device doesn\'t support speech input</string>
    <string name="tap_on_mic">Tap on mic to speak</string>
</resources>

3. Open colors.xml located under res ⇒ values and add below colors. If you don’t see colors.xml, create a new file and add the values.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="white">#ffffff</color>
    <color name="bg_gradient_start">#31244e</color>
    <color name="bg_gradient_end">#6b394c</color>
</resources>

4. Now open the layout file for main activity(activity_main.xml) and add below code to create a simple layout.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/bg_gradient"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/txtSpeechInput"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="100dp"
        android:textColor="@color/white"
        android:textSize="26dp"
        android:textStyle="normal" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="60dp"
        android:gravity="center"
        android:orientation="vertical" >

        <ImageButton
            android:id="@+id/btnSpeak"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@null"
            android:src="@drawable/ico_mic" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:text="@string/tap_on_mic"
            android:textColor="@color/white"
            android:textSize="15dp"
            android:textStyle="normal" />
    </LinearLayout>

</RelativeLayout>

5. Finally open your MainActivity.java and do the following changes. In simple adding speech input will be done in two steps.

Step 1: Starting RecognizerIntent
First we need to create a RecognizerIntent by setting necessary flags such as
ACTION_RECOGNIZE_SPEECH – Simply takes user’s speech input and returns it to same activity
LANGUAGE_MODEL_FREE_FORM – Considers input in free form English
EXTRA_PROMPT – Text prompt to show to the user when asking them to speak

Step 2: Receiving the speech response
Once the speech input is done we have to catch the response in onActivityResult and take appropriate action needed.

package info.androidhive.speechtotext;

import java.util.ArrayList;
import java.util.Locale;

import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Intent;
import android.os.Bundle;
import android.speech.RecognizerIntent;
import android.view.Menu;
import android.view.View;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

	private TextView txtSpeechInput;
	private ImageButton btnSpeak;
	private final int REQ_CODE_SPEECH_INPUT = 100;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		txtSpeechInput = (TextView) findViewById(R.id.txtSpeechInput);
		btnSpeak = (ImageButton) findViewById(R.id.btnSpeak);

		// hide the action bar
		getActionBar().hide();

		btnSpeak.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				promptSpeechInput();
			}
		});

	}

	/**
	 * Showing google speech input dialog
	 * */
	private void promptSpeechInput() {
		Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
		intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
				RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
		intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault());
		intent.putExtra(RecognizerIntent.EXTRA_PROMPT,
				getString(R.string.speech_prompt));
		try {
			startActivityForResult(intent, REQ_CODE_SPEECH_INPUT);
		} catch (ActivityNotFoundException a) {
			Toast.makeText(getApplicationContext(),
					getString(R.string.speech_not_supported),
					Toast.LENGTH_SHORT).show();
		}
	}

	/**
	 * Receiving speech input
	 * */
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		super.onActivityResult(requestCode, resultCode, data);

		switch (requestCode) {
		case REQ_CODE_SPEECH_INPUT: {
			if (resultCode == RESULT_OK && null != data) {

				ArrayList<String> result = data
						.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
				txtSpeechInput.setText(result.get(0));
			}
			break;
		}

		}
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

Run the app in a real device. Make sure that the device has good internet connectivity while you are testing.

Enabling Offline Mode

Right now all the devices are not supporting offline speech input. However you can follow this discussion to enable offline speech input for supported devices.

I have downloaded speech input packages on my Nexus 5 and offline speech is working fine.

1. On your device go to Settings -> Language and Input. Click on icon on Google voice input.
2. Under ALL tab select the language you want to download.
3. Once the language package downloaded, you can see it under INSTALLED tab.

android speech to text offline mode
android speech to text offline mode
android speech to text offline mode
Ravi is hardcore Android programmer and Android programming has been his passion since he compiled his first hello-world program. Solving real problems of Android developers through tutorials has always been interesting part for him.