What is the role and purpose of widget controllers in application architecture?

In the architecture of a Flutter application, widget controllers (such as TextEditingController, ScrollController) are used to manage the state and behavior of widgets, which are inherently immutable. They allow programmatic control over user input, scrolling, animations, and other aspects of UI interaction.

For example, a TextEditingController stores the current value of a text field and allows listening to text changes or programmatically modifying it. This separates the logic of state management from the widget itself, simplifying interface control and updates.

Thus, the role of widget controllers is to provide a connection between the UI and the application logic, managing states and events that cannot be implemented solely through declarative widgets.