What is the usage of the mvvm framework in iOS?

In iOS, utilizing the MVVM (Model-View-ViewModel) framework helps developers better separate the data model, view, and view model of the application, making the code clearer and easier to maintain.

The general steps for using the MVVM framework are as follows:

1. Create a data model: Define the data structure and relevant business logic in the application.
2. Create a ViewModel: Convert the data model into the format required by the view and provide logic for interacting with the view.
3. Creating a view: Typically designed using Interface Builder, a view is responsible for displaying data and interacting with users.
4. Bind views and view models: By using a binding mechanism, connect the presentation and user interaction behavior of a view with the data of the view model.
5. Interaction between view model and data model: The view model can retrieve data from the data model, process it, and then pass the results to the view for display.

In iOS, third-party frameworks like ReactiveCocoa, RxSwift, and Combine can be used to implement MVVM. These frameworks offer a rich set of tools and operators, making it easier and more efficient to implement MVVM.

In conclusion, utilizing the MVVM framework can help developers better organize code structure, improve code testability and maintainability, and also make the development process more flexible and efficient.