Why MVVM Over MVC ?

 Why MVVM Over MVC?

Table of Contents

1. Introduction

2. MVC and MVVM Design Patterns

3. MVC Pattern

4. MVVM Pattern

5. Conclusion

Introduction

An architectural pattern is a reusable and general solution to repetitive issues during software development. It includes architectural patterns like MVC( Model-view-controller ) and MVVM ( Model-view-view-model ).

These architecture patterns are designed to moderate the complex codes and make the UI code cleaner and manageable. Let us get you through these.

MVC and MVVM Design Patterns

Designer pattern mainly works on issues in the software application. It mainly provides solutions and practices to follow while designing software applications ( mobile applications ).

These design patterns play a significant role in developing an application as best practices formalize them loosely combined, easier to test & maintain and facilitate reusable object-oriented development.

MVC Pattern

MVC is the first and foremost architectural pattern specially designed for mobile applications and introduced in the 1970s. MVC lets you build an application with SoC – separation of concern that, in turn, eases the efforts to test, maintain and extend the application.

In a traditional software development procedure, we write a relevant code or use user control to make the view part of the defined class. This procedure increases the size of view class among business operations, data binding logic, and UI. Thus, the MVC architecture pattern is designed to reduce the code size and make a code – good code. Cleaner and easily manageable.

Model

The Model characterizes a set of classes to describe business logic. It also outlines the business rules for data on how data can be handled or changed.

View

The View stands for UI components. The View is responsible for displaying the data received from the controller as a result. The View is also used to convert the Model into the UI.

Controller

The controller is highly responsible for proceeding with incoming requests. Controller gets the user’s data through the Model to view. A controller performs as a facilitator between the Model and the View.

Separation of Concerns:

1. Model: Represents data and business logic.

2. View: Displays data to the user and handles user interactions.

3. Controller: Acts as an intermediary between the model and view, handling user input and updating the model and view accordingly.

Advantages:

4. Simple and well-known architecture.

5. Can be effective for small-scale projects with straightforward UI requirements.

6. Quick to set up and get started with.

Challenges:

7. Can lead to Massive View Controllers if not carefully managed.

8. Limited support for data binding, which can result in manual data synchronization between the model and view.

9. Can become hard to maintain as the project grows due to the mixing of responsibilities in view controllers.

MVVM Pattern 

MVVM has been defined from MVC. MVVM pattern supports two-way data binding between View and View-Model. It allows automatic propagation of modifications inside View-Model to the View. Usually, the view model uses observer patterns to change the View-model to the Mode. The MVVM has three key parts: Model: The Model has a set of classes to describe business logic. It also outlines the business rules for data on how data can be handled or changed. It is directly related to database activities.

Model

The Model has a set of classes to describe business logic. It also outlines the business rules for data on how data can be handled or changed. It is directly related to database activities.

View

The View stands for UI components. The View is accountable for displaying the data received from the controller as an outcome. It is the only user-interactive thing available. It also transforms Model (s) into the UI. The View in MVVM is active compared to MVC.

ViewModel

The ViewModel is accountable for presenting functions, methods, and commands to uphold the View’s state, operate the Model, and activate the events in the View itself. It can be defined as the Model for the application’s View

Separation of Concerns:

1. Model: Represents data and business logic, similar to MVC.

2. View: Displays data to the user but has minimal logic. It responds to changes in the ViewModel.

3. ViewModel: Acts as a bridge between the Model and the View. It exposes data and commands for the View to display and interact with.

Advantages:

4. Strong separation of concerns, leading to cleaner and more maintainable code.

5. Supports data binding, allowing automatic synchronization of data between ViewModel and View.

6. Helps in writing more testable code, as business logic is often moved to the ViewModel.

7. Allows for easier unit testing of ViewModel due to its decoupled nature.

Challenges:

8. Slight learning curve, especially for developers new to reactive programming or data binding.

9. Can introduce more files and classes compared to MVC, potentially leading to a larger codebase.

Use Cases:

MVC: Well-suited for applications where the user interface is simple and doesn't require complex interactions. Commonly used in web applications, desktop applications, and simple mobile apps.

MVVM: Ideal for applications with complex user interfaces and interactions, as well as applications that require extensive unit testing of the business logic.

MVC VS MVVM

MVC(Model View Controller)	MVVM(Model View ViewModel)
Oldest android app architecture.	Industry-recognized architecture pattern for applications.
User Inputs are handled by the Controller.	The View takes the input from the user and acts as the entry point of the application.
Controller and View exist with the one-to-many relationship. One Controller can select different View based upon required operation	Multiple View can be mapped with single ViewModel and thus, the one-to-many relationship exists between View and ViewModel.
The View has no knowledge about the Controller.	The View has reference to the ViewModel.
This architecture has high dependency on the Android APIs.	Has low or no dependency on the Android APIs.
Difficult to make changes and modify the app features as the code layers are tightly coupled.	Easy to make changes in application. However, if data binding logic is too complex, it will be a little harder to debug the application.
Limited support to Unit testing.	Unit testability is highest in this architecture.
It does not follow modular and single responsibility principle.	Follows modular and single responsibility principle.

Why MVVM is better than MVC ?

Data Binding and Automatic Updates:

• One of the standout features of MVVM is its robust data binding mechanism. MVVM allows for seamless synchronization between the View and ViewModel. When data changes in the ViewModel, the View automatically updates to reflect those changes. This eliminates the need for explicit code to update the UI, leading to cleaner and more efficient code.

Testability and Separation of Concerns:

• MVVM offers a more refined separation of concerns compared to MVC. The ViewModel encapsulates the business logic and data transformations, making it easier to unit test without involving the UI. This separation enhances the overall testability of the application and promotes cleaner code.

Maintainability and Scalability:

• MVVM's clear separation between UI logic and business logic promotes maintainable and scalable code. Changes to the UI can be made without affecting the underlying business logic, and vice versa. This separation makes it easier to update or replace individual components without disrupting the entire system.

Enhanced Collaboration:

• MVVM can facilitate better collaboration between designers and developers. Designers can focus on creating the UI elements without needing in-depth knowledge of the underlying business logic, as they interact mainly with the ViewModel. This can streamline the development process and improve the user experience.

Complex User Interfaces:

• For applications with complex user interfaces that require frequent data updates and interactions, MVVM's data binding can significantly reduce the amount of code needed to manage UI updates. This results in cleaner and more maintainable code, especially as the UI complexity increases.

Cross-Platform Development:

• MVVM is particularly beneficial in cross-platform development scenarios. Since the business logic resides in the ViewModel and is decoupled from platform-specific UI components, the same ViewModel can often be used across different platforms, reducing duplication of code and improving consistency.

Reduced Boilerplate Code:

• In MVVM, the ViewModel abstracts the presentation logic away from the View. This can lead to reduced boilerplate code in the View, as the ViewModel handles the data transformation and formatting tasks.

Scenario: To-Do List Application

MVC Approach:

• In an MVC architecture, the Model represents the data, the View represents the user interface, and the Controller manages the interaction between them.

• Model: The Model contains the data structures and business logic. In our To-Do List app, the Model might consist of the task data and methods for adding, updating, and deleting tasks.

• View: The View is responsible for displaying the user interface. It would show the list of tasks and provide buttons for actions like marking a task as completed or deleting it.

• Controller: The Controller handles user input and manages the interaction between the Model and the View. It listens for user actions in the View and updates the Model accordingly.

MVVM Approach:

• In the MVVM architecture, the Model, View, and ViewModel components are utilized.

• Model: The Model remains the same as in the MVC approach, containing the task data and business logic.

• View: The View displays the UI, but it doesn't directly interact with the Model. Instead, it binds to properties exposed by the ViewModel.

• ViewModel: The ViewModel acts as an intermediary between the Model and the View. It exposes properties and methods that the View binds to. For our To-Do List app, the ViewModel would expose an array of tasks and methods to manipulate them.

Advantages of MVVM in this Scenario:

Data Binding:

In MVVM, the ViewModel can expose an array of tasks. When a new task is added or a task's status changes, the ViewModel automatically updates its array, and this change is seamlessly reflected in the View through data binding. This reduces the need for manual updates and makes the UI always reflect the actual data state.

Separation of Concerns:

MVVM clearly separates the UI-related logic from the business logic. The ViewModel handles the task manipulation and transformation, while the View focuses solely on displaying the data. This separation makes the codebase cleaner and more maintainable.

Testability:

The ViewModel can be unit tested easily, as it encapsulates the business logic. This allows for thorough testing without involving the UI components, leading to more reliable code.

Flexibility:

If you decide to change the UI design or add new features, the ViewModel's structure remains unchanged. This flexibility ensures that UI changes do not affect the underlying business logic.

Enhanced User Experience:

With data binding, UI updates are automatic. When a task is marked as completed, the UI reflects this change instantly, enhancing the user experience and making the app feel responsive.

Conclusion:

In this scenario of a To-Do List application, MVVM's data binding, separation of concerns, testability, flexibility, and improved user experience make it a better choice over MVC. The ViewModel acts as a bridge that streamlines communication between the Model and the View, resulting in a more maintainable, adaptable, and user-friendly application.