MVVM (Model-View-ViewModel) architecture in Android is a design pattern that separates the concerns of an application into three distinct layers: the Model, the View, and the ViewModel. MVVM architecture promotes a clean separation of concerns, making it easier to manage and test code, enhance code readability, and facilitate collaboration among developers.
At its core, MVVM architecture consists of the following components:
Model: The Model represents the data and business logic of the application. It encapsulates the data sources, such as databases, network services, or repositories, and defines the business rules and operations that manipulate the data. In MVVM architecture, the Model layer is independent of the UI and does not contain any references to the View or ViewModel.
View: The View represents the UI components of the application, such as activities, fragments, or layouts. It is responsible for rendering the user interface and handling user interactions. In MVVM architecture, the View layer is passive and does not contain any business logic. Instead, it delegates data binding and event handling to the ViewModel layer.
ViewModel: The ViewModel acts as an intermediary between the View and the Model. It exposes data and operations that the View can bind to and interact with. The ViewModel retrieves data from the Model, processes it, and prepares it for presentation in the View. It also handles user interactions and updates the Model accordingly. In MVVM architecture, the ViewModel is responsible for maintaining the state of the UI and managing the communication between the View and the Model.
One of the key features of MVVM architecture is its support for data binding, which enables automatic synchronization of data between the View and the ViewModel. By using data binding, developers can bind UI components directly to ViewModel properties and methods, eliminating the need for manual event handling and synchronization code.
Another advantage of MVVM architecture is its support for testability. Because the ViewModel is decoupled from the View and the Model, it can be easily unit tested in isolation, allowing developers to write robust and reliable tests for the application’s business logic.
