//We know that now a days apps like watsapp automatically read otp from messages //so this post will show you how to do that programatically.

//First of all we need Broadcast Reciever that will announce broadcast that a new //message has arrived.

        //In this broadcast we basically check for message number that we are //recieving and check that is correct or not.

public class SmsReciever extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent)
    {
        Bundle myBundle = intent.getExtras();
        SmsMessage [] messages;
        String mMessageFrom = null;
        String mMessageBody = null;
        String mOtp = null;

        if (myBundle != null)
        {
            Object [] pdus = (Object[]) myBundle.get("pdus");

            messages = new SmsMessage[pdus.length];

            for (int i = 0; i < messages.length; i++)
            {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                    String format = myBundle.getString("format");
                    messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i], format);
                }
                else {
                    messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
                }

                String phoneNumber = messages[i].getDisplayOriginatingAddress();
                mMessageFrom = phoneNumber ;
                mMessageBody = messages[i] .getDisplayMessageBody();

            }

            if (mMessageFrom != null) {
                if (mMessageFrom.equals("DM-ADHAAR")){
                    Matcher m = Pattern.compile(
                            Pattern.quote("is ")
                                    + "(.*?)"
                                    + Pattern.quote(" and")
                    ).matcher(mMessageBody);
                    while(m.find()){
                        mOtp = m.group(1);
                    }
                }
            }
            SocialMediaActivity socialMediaActivity = SocialMediaActivity.instance();
            socialMediaActivity.updateOTP(mOtp);
        }
    }

}

//And in Social Media activity we checks for activity instance and call the method //to update edittext like this :

private static SocialMediaActivity mSocialMediaActivity;

public static SocialMediaActivity instance() {
    return mSocialMediaActivity;
}

@Override
public void onStart() {
    super.onStart();
    mSocialMediaActivity = this;
}

public void updateOTP(String otp){

    etAadhaarOtp.setText(otp);

}

//so we call this method from our broadcast reciever.