As of now, 76.8% of the total populace is digitalized. With the quick reception of smartphones and tablets, organizations are looked at with an ever-increasing number of chances each day that will profoundly change how their administration or item is conveyed and gotten to. There are more mobile devices than the aggregate number of PCs and TV units joined, which means your business needs a mobile presence to remain associated with its clients. In today's date, the mobile application is a very aggressive market, there are hundreds of platforms to choose from when designing applications. There are several platforms that currently dominate over other platforms. Google's Android platform and Apple's iOS platform are very popular these days. In a recent study, it is seen that around 72.26% of the total smartphone users use the Android platform, 27.03% use the iOS platform and the rest 0.7% use the other platforms available in the market. From this data, you may think that having an Android app for your business is enough as it will cover 70% of the smartphone users, but you will miss out on the rich and wealthy 27% of users who can afford Apple's smartphones and use the iOS platform. The android platform requires apps to be written in JAVA (or Kotlin), and the iOS platform requires Swift. This implies that you'll require two different teams who will work on the Android and iOS apps. This solution may seem efficient but it is not budget-friendly, as hiring a mobile app engineer is not cheap. Hence what's the solution then? Well, here comes Google's Flutter!
Flutter is a "tool" that allows you to build native cross-platform (iOS and Android) apps with one programming language and codebase. An important point to be noted here that using flutter we are NOT building a web app that runs in the browser, or an app that gets wrapped by native apps, we build real apps, two different kinds of apps in the end for iOS and Android, which you then distribute through the different app stores, i.e., the Apple App Store and the Google Play store. Now you get there by using one programming language so that you don't have to learn two different programming languages, one for iOS, one for Android, instead, you have one programming language called Dart and also one codebase. That implies you work in one project, you write your code once and you still get two different apps as a result. Cool isn't it?
If we have a closer look at flutter though, it is actually a combination of two things— an SDK (Software Development Kit), and a framework, a widget library for that one programming language (Dart) which you can use to build beautiful Flutter apps! The widget library gives you a vast collection of reusable UI building blocks, the so-called widgets like buttons, tabs, text inputs, dropdowns, etc all out of the box! You can style them customize them and then you build user interfaces with these tools. In addition, you get a couple of utility functions and generally, some packages that help you build what your users see and what your users interact with and then that code which you built with the help of that framework, that is then compiled native machine code with the help of the SDK.
Now besides this rough idea of how we build our apps in Flutter, it's also important to understand that Flutter apps do actually embrace platform differences, whilst being based on one codebase, so we work in one project but we will still have the ability to create different user interfaces at some points or in some parts of our app if we need it for the different platforms because Android and iOS are not exactly the same. They're not just for different phones, they do have some small differences and sometimes, that doesn't matter to you but if it does, Flutter gives you the tools to find out on which platform you're running, so that if you're on Android, you can execute code A and if you're on iOS, you can execute code B, so Flutter gives you the full flexibility there. Flutter has got it all!
So now that we know what Flutter is or that we at least have a rough idea about that, let's have a look at the architecture of a Flutter application. Before we proceed, here is an important thing to note: Flutter has that idea of building user interfaces as code, that's called UI as Code, and unlike android app development in Android Studio with JAVA, there will be no visual drag and drop editor for adding widgets (however there are some third-party IDEs that still offer that, however, things become compilated when you use such services), instead we have to write everything in code. This may sound intimidating at first but you will see the Flutter has a really nice approach for that, which makes creating interfaces with this UI as Code approach a breeze!
In Flutter, everything's a widget, that's important to understand. If you had an app that looks like this, then this is a bunch of widgets. For example here, the app bar at the top with the text "iCrew Blogs" in there, the body of the app that's one huge widget with a lot of smaller widgets like buttons and text in there, all those elements on the screen are just widgets!
The whole page is a widget and even the whole app is wrapped in one main widget and a widget is really just a code snippet, an instruction you placed in your code. It'll be as simple as that and your entire app is therefore built as a widget tree. You have this root widget which is your app itself, then you might have different screens there, on the different screens, you have different sections and in there you might have text inputs, text outputs, buttons, tabs, dropdowns, and a widget might hold other widgets, for example, your tabs widget might hold individual tab widgets. So that is how the architecture of a flutter application looks. Cool!
By now you might be thinking, how does flutter turn my dart code into native applications? Because let's say for android, native applications will require code to be written in JAVA or Kotlin, and Dart code will simply not work! Well here's the answer—
Flutter simply compile that Dart code to native code for these different platforms and that happens with the help of the Flutter SDK and as a result, we get real apps to spit out with highly optimized high-performance code that's based on our code ut that's not our code itself, instead, it's the compiled version of that code and therefore we really ship code that runs on the different platforms and that's optimized and high performant because performance is actually a huge advantage of Flutter apps, Flutter out of the box gives us high-performance applications.
Now in case, you worked before with let's say React Native which is kind of an alternative to Flutter it's important to understand that Flutter does not use platform primitives. Now, what do I mean with that? We're having our Flutter app and we're targeting iOS and Android. Now if we want to add a button then in Flutter with this UI as Code approach, we do so by adding, let's say, a RaisedButton. Now, this is just an instruction in your Flutter code which tells Flutter to render a button in that part of your widget tree. Now you could think that what happens when the code gets compiled to that native code is that this RaisedButton is translated to the native buttons which are of course part of the native development environments and that's not what happens. Instead, Flutter has its own implementations because Flutter directly controls every pixel on the screen. So Flutter does not compile your code to some native equivalence or native alternatives, instead, Flutter ships with its own engine which controls the entire screen, everything the user sees and renders every pixel on its own and that gives Flutter a lot of control and a lot of flexibility. So, in simpler terms, flutter does not directly translate anything to native code, instead, it makes its own UI, and that's what gives us a boost in performance and fewer limitations. Interesting isn't it?
Now if you might be thinking "Hey I've already used React Native and Ionic, does flutter differ from them in any way?" Well, my answer is yes, of course, it does!
Now, to sum up, I would like to mention a few key points again. Flutter is a "tool" that allows you to build native cross-platform apps with one programming language and one codebase. Flutter consists of two things, one is Flutter SDK and the other is the widget library and framework so that you create the best app possible. A flutter app consists of a Widget tree and every UI component in flutter is just a widget. This approach makes it easier to code and analyze it. Flutter UI does not get translated to native UI, instead, Flutter has its own UI written in native code, which makes flutter performance-friendly and gives us a whole lot of options to customize UI. Flutter has a few competitors too, but all of them work in a different way. Flutter is regularly updated to bring new functionalities, and that is why developers prefer it so much these days!