Penerapan Design Pattern Observer Pada Pengembangan Aplikasi Android (Studi Kasus : Aplikasi "KataFilm")

The impact of mobile applications on various aspects of life has brought about profound changes in the digital era. However, the rapid development in this field also poses challenges for IT companies, particularly in rapidly developing applications without considering code quality. For instance, at the Software House where the author works, a company faced difficulties during the development process of its application. The use of inappropriate design patterns, especially the Chain of Responsibility design pattern, became the root cause of the problem, leading to excessive module interdependence, hindering flexibility, and compromising the maintenance process.
Similar issues occurred in an application the author previously developed, namely the KataFilm application. To address these challenges, this research focuses on implementing the observer design pattern in the KataFilm application. Previously, the application used the Chain of Responsibility design pattern, which was considered suboptimal, particularly in terms of maintainability.
By analyzing the negative impacts of the previous design, this research aims to create a more efficient and easily maintainable solution through the implementation of the observer design pattern. This step is expected not only to rectify the specific issues in the KataFilm application but also to provide a positive contribution to understanding and applying more effective design patterns in the mobile application industry in Indonesia.