Blog School of Programming How to Code an App: An Overview of Mobile App Development

How to Code an App: An Overview of Mobile App Development

With consumers spending more than 180 billion hours inside smartphone apps every month, the attractiveness of mobile app development continues to rise, and many developers are learning how to code mobile apps from scratch. 

In this article, we’ll first go through the different types of apps, before taking a closer look at mobile app coding in practice.

App Development

In-app development, the most fundamental distinction is that between web apps and mobile apps. Web apps require an active internet connection to run, whereas mobile apps work offline. Web apps on smartphones are simply mobile-optimized web pages, while mobile apps need to be downloaded from a phone’s app store.

Mobile apps are superior in terms of efficiency and speed but do require users to manually or automatically download updates rather than updating themselves, as web apps do. Mobile app development tends to be more resource-intensive than web app creation, but mobile apps are faster and usually functionally outperform their web counterparts. For example, mobile apps often use phone features like cameras that web apps usually don’t have access to.

You may be surprised to learn that there are several kinds of mobile apps, so we’ll proceed by distinguishing between the two major types: native apps and cross-platform apps.

Native Apps vs. Cross-Platform Apps

Native applications are those built with a given operating system (OS) in mind, using specific programming languages and Integrated Development Environments (IDEs). For example, a native application for iOS should be written in the language that iOS expects, using the APIs that iOS exposes. If developers use Objective-C and Swift for an iOS app, or Java for an Android app, along with the appropriate APIs, such applications are “native” insofar as the underlying system’s capabilities are used as expected by the system. Native apps also use hardware memory, camera, sensors, and other programs installed on a device through the APIs exposed by the underlying system. 

By contrast, cross-platform frameworks intend to provide universal solutions supported by several mobile OSs at once. They use a common core with per-platform customizations to fit an application to multiple platforms, so there’s no need to create unique elements for each OS.

What are the advantages and challenges of each mobile app approach? 

Native apps offer higher performance, greater energy efficiency, fewer limitations in architecture and functionality, and an interface fully compliant with the given platform’s guidelines. However, maintaining them comes at a high price: Mobile apps sometimes get multiple updates each month, and keeping them up-to-date can consume developer time that could otherwise be spent on new functionality. Also, a native app’s audience is limited to users of one particular OS, unless its creators exert considerable effort in developing the same app for multiple systems. 

Conversely, cross-platform apps facilitate code-sharing, as developers don’t have to create one app for iOS and a separate one for Android, but are often able to share 80% or more of their code across platforms. Less coding effort required allows the app to be maintained on multiple platforms, even with a small team.

However, It’s difficult to tailor a single solution to various operating systems. A cross-platform solution is designated as such precisely because its framework allows you to use multi-platform functionality. A cross-platform application’s interface is usually universal, leading to lags and complexities when implementing specific elements of each OS, as features unique to a particular platform typically won’t be supported. While a framework might make an app look and feel like its intended platform, without any additional work from the developer, design choices are usually limited.

Now let’s take a closer look at the toolchains required for both app types, and further distinguish between even more variations of mobile apps within the cross-platform ecosystem.

Native Apps

In native app development, familiarity with your chosen operating system’s IDE and project structure is imperative. Fortunately, the iOS and Android operating systems are well-documented and provide their own development tools, interface elements, and software development kits (SDKs), which developers can use to build native mobile apps.

Apple devices run on the iOS native operating system and are built using either Objective-C or Swift along with the Xcode IDE. Despite being two separate platforms, iOS and macOS share similarities, so if you want to run your mobile app on an Apple desktop, you can incorporate modern iOS features into your app. This will simplify the transition to macOS (since up-to-date features automatically map to appropriate macOS behaviors).

By contrast, the Android development toolchain usually involves Android Studio or the Eclipse IDE, though you may also use other IDEs. Android Studio is the official IDE for Android app development, and the main program for writing code and assembling apps from various packages and libraries. Both Android Studio and the Android SDK are free to download and come with software libraries and sample code. While Android apps are built with Java, you could build an Android app in other languages that run on the Java Virtual Machine, such as Kotlin.

Hybrid Cross-Platform Apps

There are two different types of cross-platform apps: hybrid apps and native cross-platform apps. Hybrid apps use only HTML5, CSS, and JavaScript to create parts of an app’s graphical user interface (GUI). Sound like a web app? Whereas both hybrid mobile apps and web apps render HTML, hybrid apps use app-embedded browsers like WebView to do so.

Some hybrid apps even interact with a smartphone’s hardware, although the functionality can be limited. Apache Cordova, Ionic, and Flutter are among the most promising hybrid app development frameworks currently on the market.

Native Cross-Platform Apps

Native cross-platform apps, on the other hand, are not built with HTML/CSS/JS frameworks — a developer would instead create a unified API running on top of a native SDK. By making use of a native IDE coupled with this API, a developer can build iOS and Android apps that share the same codebase while providing a near-native experience. Native cross-platform applications are primarily built with Xamarin, React Native, and Kotlin Multiplatform.

This may sound confusing, so let’s look at how one such mobile UI framework works. We’ll take the case of Xamarin. 

Built with C# and .Net, Xamarin allows developers to create cross-platform applications with shared interfaces using Xamarin.Forms. Xamarin.iOS and Xamarin.Android are particularly useful for creating iOS and Android interfaces. In addition to providing libraries that grant native and third-party API access, Xamarin gives cross-platform apps access to smartphone hardware and functionality previously only found in native apps. By combining near-native performance with code reusability, native cross-platform frameworks narrow the performance gap between native and hybrid apps with the potential for more cost-effective development.

Where Should You Start?

If you want to take advantage of everything a given mobile platform has to offer, try building a native mobile app. Your app will likely boast higher performance, more robust functionality, and a better user experience as compared to a cross-platform counterpart. Developing with a particular SDK is a great starting place as you’ll face a more manageable learning curve relative to cross-platform code. 

Choosing a platform-independent option might be the best choice for those looking for easy maintenance and broader reach, and with shorter time to develop. As long as you choose the right tech stack, you may be able to reuse the majority of the original backend and UI code for multiple platforms.

If you do choose to go the multi-platform route, how do you know whether to opt for a hybrid (JS/HTML/CSS) or native cross-platform app? If you’re looking for an easy start and don’t know mobile, try the JS/HTML/CSS approach. If you’re seeking a near-native experience but would like to be on multiple platforms (and can’t invest in an app for each platform), go native cross-platform.

Learn More

In this article, we went over the differences between mobile apps and web apps, before taking a closer look at various mobile apps types. We covered native apps, hybrid cross-platform apps, and native cross-platform apps. 

If you envision a career in mobile app development, our Introduction to Programming Online Course will provide a solid foundation for working with both cross-platform and native apps.

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