Cannot resolve symbol retrofit

Question

I followed this example https://futurestud.io/tutorials/oauth-2-on-android-with-retrofit

    public static <S> S createService(
            Class<S> serviceClass, final String authToken) {
        if (!TextUtils.isEmpty(authToken)) {
            AuthenticationInterceptor interceptor =
                    new AuthenticationInterceptor(authToken);

            if (!httpClient.interceptors().contains(interceptor)) {
                httpClient.addInterceptor(interceptor);

                builder.client(httpClient.build());
                retrofit = builder.build();
            }
        }

        return retrofit.create(serviceClass);
    }

but at retrofit = builder.build() I got cannot resolve symbol. Please help.

Answer 1

Sometimes when you download projects from a version control system the files get locked, so in my case to solve this i had to uncheck the "only read" box then apply and accept.