How to resend SMS verification in Firebase Phone Authentication Android?

Updated code

fun resendOTP(activity: Activity,mobileNo: String){
    val options = PhoneAuthOptions.newBuilder(auth)
        .setPhoneNumber(mobileNo) // Phone number to verify
        .setTimeout(60L, TimeUnit.SECONDS) // Timeout and unit
        .setActivity(activity) // Activity (for callback binding)
        .setCallbacks(callback) // OnVerificationStateChangedCallbacks
        .setForceResendingToken(resendToken!!) // ForceResendingToken from callbacks
        .build()
    PhoneAuthProvider.verifyPhoneNumber(options)
}

For java see Github

Thanks to GGWP for link .

Source: Firebase Quickstarts for Android

This is the method used to resend SMS Verifications.

private void resendVerificationCode(String phoneNumber,
                                    PhoneAuthProvider.ForceResendingToken token) {
    PhoneAuthProvider.getInstance().verifyPhoneNumber(
            phoneNumber,        // Phone number to verify
            60,                 // Timeout duration
            TimeUnit.SECONDS,   // Unit of timeout
            this,               // Activity (for callback binding)
            mCallbacks,         // OnVerificationStateChangedCallbacks
            token);             // ForceResendingToken from callbacks
}

you can use a Firebase method to resend verification code as say PERSISTENCE and intercept sms code for to check in automatic, for instance while run a progress dialog, and transparent to the user, simply which

// [START resend_verification]
public void resendVerificationCode(String phoneNumber,
                                   PhoneAuthProvider.ForceResendingToken token) {
    PhoneAuthProvider.getInstance().verifyPhoneNumber(
            phoneNumber,        // Phone number to verify
            60,                 // Timeout duration
            TimeUnit.SECONDS,   // Unit of timeout
            activity,           //a reference to an activity if this method is in a custom service
            mCallbacks,
            token);        // resending with token got at previous call's `callbacks` method `onCodeSent` 
    // [END start_phone_auth]
}

check the sms with broadcast receiver in a fragment

private BroadcastReceiver smsBroadcastReceiver;
IntentFilter filter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
public static final String SMS_BUNDLE = "pdus";

 @Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    smsBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.e("smsBroadcastReceiver", "onReceive");
            Bundle pudsBundle = intent.getExtras();
            Object[] pdus = (Object[]) pudsBundle.get(SMS_BUNDLE);
            SmsMessage messages = SmsMessage.createFromPdu((byte[]) pdus[0]);
            Log.i(TAG,  messages.getMessageBody());

            firebaseVerificationCode = messages.getMessageBody().trim().split(" ")[0];//only a number code 
            Toast.makeText(getContext(), firebaseVerificationCode,Toast.LENGTH_SHORT).show();
            String token = firebaseAutenticationService.getVerificationCode();//your service
        firebaseAutenticationService.verifyPhoneNumberWithCode(token,verificationCode);
        }
    };
}