Overview

General Overview

A good way to demonstrate the library's functionality without technical details is with this scheme: in the WidgetModel, we determine what to display to the user and manage the business processes running behind the scenes.

Technical Overview

Elementary follows classical MVVM layering, comprising the View, ViewModel, and Model layers. Each layer is represented by a specific entity: ElementaryWidget for the View layer, WidgetModel for the ViewModel layer, and ElementaryModel for the Model layer.

To naturally integrate this chain of entities into the Flutter trees, the following decisions were made:

• An ElementaryWidget, like all other widgets, is simply a configuration and an immutable description of a part of the user interface.
• An ElementaryWidget is a component widget (represented by a ComponentElement), meaning it describes its subtree as a combination of other widgets.
• A representation of an ElementaryWidget in the Element tree is a special Element called Elementary.
• Elementary creates a WidgetModel using a factory method from ElementaryWidget and then stores and manages it.
• The lifecycle of the WidgetModel is connected to the Elementary lifecycle, as indicated in the previous statement.
• A WidgetModel depends on an ElementaryModel, stores it, and manages its lifecycle.
• When a subtree needs to be described, Elementary delegates to the build method of ElementaryWidget, providing the WidgetModel. This represents UI=f(State) in the form subtree=build(WM).

The following diagram illustrates how these components work when an ElementaryWidget is inserted into the tree: