With my extensive 7 years of experience as a mobile app developer, specializing in Android and iOS platforms, I can confidently assert that I'm the best fit for your project's needs. Over the course of my career, I have been involved with a multitude of successful projects, each contributing to my growing knowledge base. My understanding of UI/UX design goes beyond mere aesthetics; it emphasizes on creating an intuitive and smooth user experience - a key aspect in this sticker integration project.
Moreover, being competent in Android and iOS development, I assure you expert execution of integrating the button feature into your unpublished Goodbarber app. Even though you describe it as a straightforward task, it inherently requires comprehensive technical insights and domain knowledge - something that I possess abundantly. My proficiency in sticker integration for WhatsApp would be invaluable here.
All in all, if you're looking for not just a coder but a true professional who will work tirelessly to bring your vision to life with precision, hire me! Together, we can create an exceptional app that enhances your users' experience while keeping it simple and intuitive. Just click the "Hire Me" button to get started!