Describe the process of creating a complex custom widget that integrates with other app functionalities.

Creating a complex custom widget involves utilizing a combination of composition and state management patterns. This typically includes breaking down the widget into smaller, reusable components, efficiently managing the widget's state, and integrating it with other app functionalities. Utilizing composition allows for better code organization and maintainability, while effective state management ensures that the widget behaves correctly and efficiently interacts with the app's overall state.