最后得到了解决方案. 在验证用户身份的过程中，我们仅使用添加新参数的方法来发送代码.

Finally got the solution. During authenticating the user, we use the same method for sending the code only that we add a new parameter.

PhoneAuthCredential credential = PhoneAuthProvider.getCredential(verificationId, code);
    signInWithPhoneAuthCredential(credential);
    Toast.makeText(this, "Verifying...", Toast.LENGTH_SHORT).show();