MarsDevs introduces you to Mobile App Architecture!

Mobile app architecture is a defined set of rules, processes, techniques, and patterns that assists you in developing a mobile application. These rules help you create an app that meets business requirements, user expectations, and industry standards.

In this blog, MarsDevs introduces you to the Mobile App Architecture, its importance, and its utility.

The difference: Mobile App Architecture vs. Mobile Tech Stack

You can often use Mobile app architecture interchangeably, although incorrectly, with the mobile tech stack. The mobile technology stack is the set of technologies and technical frameworks that help a developer make up the front and back end of a mobile or web app. 

It is less concerned with the business or customer requirements, which comprises the why of the app or the development process, i.e., the how of creating the app.

The mobile app architecture comprises all the parts of the app – all the questions about why, what, and how. It also includes what data is collected, how the information moves, what the app might look like, for what platform, and the tech stack.

How can you spot a Good Mobile App Architecture?

Many apps developed today lack architecture or reference to standards. 

You can spot a lack of architectural results in an app through:

  • The more prolonged and more costly development process
  • Complexity in maintenance, particularly if staff change
  • Harder to build upon or scale
  • Difficulty in testing
  • More prone to errors than general

An excellent mobile application architecture will enforce good software development principles in the appropriate stages of development. This helps you accelerate development, providing a clear path for the data flow to make work easier and supports clarity over how to scale or expand the app in the future.

A clearly defined mobile app architecture supports flexibility and Agile development methods, makes testing more efficient, and makes future maintenance more accessible and less prone to bugs. A robust mobile app architecture will save time and money in the short and long term.

A good architecture will not be platform specific but rather apply to native and cross-platform choices. This approach results in a unified approach to development. If a mobile app architecture is a skeleton for how we create a mobile application, we can then define layers for how we build out the vital components of the app.

How Many Layers Are There in Mobile App Architecture?

The most famous representation of mobile app architecture has three layers: presentation, business logic, and data.

  1. Presentation Layer 
    The presentation layer consists of all the processes and components that help us deliver the app to our users. When you build the presentation layer, you concern yourself with what the user sees and feels when using the app. In other words, the presentation layer comprises the user interface (UI) and user experience (UX).
  • User Interface (UI) concerns design questions such as colors, fonts, placement, and overall design.
  • User Experience (UX) manages how a customer interacts with the app by understanding what a user wants and feels.

When designing the presentation layer, you should be able to decide on the right platform and device type so you can make it consistent with each standard.

2. Business Layer 
The business layer concerns itself with the logic and rules that are responsible for data exchange, operations, or workflow regulation. This layer is accountable for the following:

  • Security
  • Data caching
  • Logging
  • Data validation
  • Exception management

The business layer can exist on the server or the user device. It depends on the app's operations and the resources that each procedure might take.

3. Data Layer 
The data layer includes all the data utilities, service agents, and access components that support data transactions. This layer can be thought of in two parts:

  • Persistence – data access with data sources via API, and
  • Network – network communication, error reporting, routing,

The design of the data layer must include thoughts about the validation and maintenance of the data.

MarsDevs recommends you an app architecture!

If you consider the common architectural principles, each application should have at least two layers:

  • The UI layer to display application data on the screen.
  • The data layer to contain the business logic that reflects your app and exposes the application data.

You can add another domain layer that simplifies and reuses the interactions between each of the UI and data layers.

UI layer

The UI layer, also known as the presentation layer, helps you display the application data on your screen. So, whenever you see the data change, it changes either due to the user interaction, i.e., pressing a button, or due to some external input, i.e., a network response. The UI should update and reflect the changes every time you change something.

The UI layer comprises two things:

  • Its elements which render the data on your displayed screen. You can build these elements yourself using Views or Jetpack Compose functions now.
  • State holders. Consider ViewModel classes. They can hold data and expose it to the UI to handle logic.

Data layer

The data layer in an application contains the business logic. The business logic can give value to your app. But you need to know its rules, which can determine how your app can help you create, store, and change data.

The data layer is made with repositories. Each of them can contain zero to as many data sources as you need. You need to create a repository class for each type of data you handle in your app. 

You can create a MoviesRepository class for data that are related to movies or a PaymentsRepository class for data that you can relate to payments.

Repository classes are responsible for different tasks:

  • To expose data to the rest of the application.
  • To centralize the changes to this data.
  • To resolve conflicts between multiple data sources.
  • To abstract sources of data from the rest of the application.
  • To contain the business logic.

You should let each data source class be responsible for working with only one data source, a network source, a file, or a local database. Data source classes can thus bridge the gap between the application and the system that we use for data operations.

Domain layer

The domain layer is often treated as an optional layer that can sit between the UI and the data layers.

The domain layers are often responsible for encapsulating complex business logic or even the simple ones that are reused by multiple ViewModels. The domain layer is optional, as not all apps have these requirements. It would be best if you used it only as you need, for example, in situations that require you to handle complexity or favor reusability.

You often know the classes in this layer as use cases or interactors. Each of these use cases further takes responsibility for a single functionality. Consider your app. Now, it has a GetTimeZoneUseCase class. In this case, multiple ViewModels rely on time zones in order to display the proper messages on the screen.

MarsDevs Tips:

  • Follow the dependency injection patterns and use the Hilt library for the Android applications. 
  • It automatically constructs objects by walking the dependency tree and provides compile-time guarantees on dependencies.
  • It also creates dependency containers for Android framework classes.

General practices that can help you through the journey.

While it does not seem like one, programming is a creative field. Also, building Android apps is not an exception. There can be several ways to solve a particular problem. And you might need to communicate data between multiple activities to retrieve that remote data and persist it locally to enable the offline mode or handle any other common scenarios that a nontrivial app might encounter.

Following recommendations can always be optional. Prescriptions are not recommended either. But knowing about them can often help you make your code base more robust, testable, and easily maintainable in the long run.

  • Do not store data in the app components. 
    You need to avoid designating your application's entry points, i.e., activities, services, and broadcast receivers—as data sources. Instead, they should only be able to coordinate with other components in order to retrieve the relevant data subset to that entry point. Each app component is relatively short-lived and depends on the user's interaction with their device. It also depends on the overall health of your system.
  • Reduce your dependencies on the Android classes. 
    Your app components need to be the only class that relies on Android frameworks SDK APIs such as Context or Toast. Abstracting other classes away from your app helps you with testability as it reduces coupling within your application.
  • Create well-defined boundaries of responsibility between the various modules in your application. 
    Keep the code that can help you load data from the network across multiple packages or classes in your code base. Similarly, you do not need to define multiple unrelated responsibilities, including data caching and binding, in the same class. If you follow a pre-structured app architecture, it can help you with it.
  • Only expose some from each module. 
    Create a shortcut that can help you expose an internal implementation detail from one module. That might help you gain a bit of time if you consider the short term, but you are more likely to incur technical debt over and over as your codebase evolves with time.
  • Persist in relevant and fresh data. 
    If you persist, your users could enjoy your application's functionality even when they have a device offline. You still need to note that only some of your users want constant, high-speed connectivity. And, even if they do, they can get lousy reception in most crowded places.

Some Benefits of the Mobile App Architecture

Having a good Architecture executed in your application can introduce a lot of benefits to your project and development teams:

  • It can help you improve your overall app's quality, maintainability, and robustness.
  • It allows your app to scale. More people and teams could contribute to the same codebase with minimum code conflict.
  • It also helps you with onboarding. As architecture brings consistency to your project, new team members can quickly get updated to speed and be more productive in less time.
  • It is easier to test. A good Architecture helps you encourage more specific types, which are generally easier to test.
  • You can investigate bugs methodically with well-defined processes.

Investing in Mobile App Architecture can also directly impact your users. 

Build an innovative mobile application for your brand and outgrow the best with MarsDevs.

The mobile application development process is complicated. It would be best if you had a team of developers for the job. Again, we understand how tiring it is to balance business and hiring. You even have to hire and fire to decide on a perfect team. But it is the age of digitization, and every problem has a quick and easy solution. MarsDevs makes it affordable too. 

Why invest time in hiring when we can chip in anytime you want? MarsDevs takes care of all your development needs while you focus on business. Your applications stand out with excellent UIs; this is just the start.