Original subtitles

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Now how does Flutter and Dart therefore then work internally? How is your Flutter app actually converted

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to a native app which can be published to the app stores? Well you have your Dart code which uses the

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Flutter framework or the Flutter API as I call it here, which stands for application programming interface.

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In the end that just means that Flutter gives you a collection of functions, of widgets, which you can

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use in your code to build the interface you want to build.

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So you have your own widgets and your own code then composed of that set of built-in widgets or your

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own widgets which you can also build and you want to build for Android and iOS.

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Now as I said, Flutter simply compile that Dart code to native code for these different platforms

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and that happens with the help of the Flutter SDK

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and as a result, you get real apps spit out with highly optimized high performance code that's based

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on your code

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but that's not your code itself,

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instead it's the compiled version of that code and therefore you really ship code that runs on the different

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platforms

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and that's optimized and high performant because performance is actually a huge advantage of Flutter

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apps, Flutter out of the box gives you high performance applications.

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Now in case you worked before with let's say React Native which is kind of an alternative to Flutter and I'll

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come back to this in a second,

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it's important to understand that Flutter does not use platform primitives.

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Now what do I mean with that? We're having our Flutter app and we're targeting iOS and Android.

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Now if we want to add a button then in Flutter with this UI as Code approach, we do so by adding a

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RaisedButton.

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Now this is just an instruction in your Flutter code which tells Flutter to render a button in that part

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of your widget tree.

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Now you could think that what happens when the code gets compiled to that native code is that this

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RaisedButton is translated to hey iOS,

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please give me your default button, which would be a UI button element in the iOS development world and

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for Android, a widget.button, that we get these native buttons which are of course part of the native

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development environments

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and that's not what happens.

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Instead Flutter has its own implementations because Flutter, and that's really important to understand

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and to keep in mind, directly controls every pixel on the screen.

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So Flutter does not compile your code to some native equivalence or native alternatives, instead Flutter

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ships with its own engine which controls the entire screen, everything the user sees and renders every

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pixel on its own and that gives Flutter a lot of control and a lot of flexibility.

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Now you don't have to care too much about that because Flutter does it for you but it's important to

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be aware of that because that gives Flutter more control and less limitations and therefore, you implicitly,

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indirectly benefit from that.

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You have a good performance,

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you have a lot of power, a lot of things you can configure,

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you have full control over how you want to build your user interface.