Flutter widget is built using a modern framework. It is like a react. In this, we start with the widget to create any application. Each component in the screen is a widget. The widget describes what his outlook should be given his present configuration and condition. Widget shows were similar to its idea and current setup and state.
Flutter automated testing empowers you to meet high responsiveness in your application as it helps in discovering bugs and various issues in your application. A Flutter is a tool for developing mobile, desktop, web applications with code & is a free and open-source tool.
Hello friends In this blog, we will learn about Under the hood rendering in flutter?. In this, we will see how Flutter provides an overview of the architecture and how to execute dart’s code behind the scenes in mobile. so let’s get started.
Table Of Contents :
Flutter architectural Overview
Let’s go through this rendering stepwise manner
How to run flutter code runs on the device
Flutter Rendering:
The rendering layer in the flutter is an abstraction dealing with the layout. This lets you build a tree of objects to render. All of these objects can be dynamically manipulated. The tree detects our objects and automatically updates the layout for its changes.
Flutter widgets are reactive. They respond to any new information from an outside source. Consider a Stateful component as a parent to another Stateless component.
In that case whenever one of the states on which the stateless component was relying on changes, the widget calls didUpdateWidget life cycle method and repaints if necessary. For example:
IconButton(
icon: Icons.add,
onPressed: (){
setState((){
this.value++;
})
}
),
Text("Value = ${this.value}")Flutter architectural overview:
There are mainly three layers in the architecture of Flutter, each layer has a set of libraries, let us see them in detail.
- Framework
- Engine
- Embedder
=> Framework: To interact with Flutter, developers use the Framework layer, which is written in the Dart language. It provides a modern responsive framework. It consists of a variety of components. It includes high-level widgets such as animations, rendering logic, etc. Cupertino also provides libraries such as Material that help implement iOS designs and Material Design.
Components of Framework:
- Foundation: It’s a kind of basic foundation class that provides building blocks such as painting, animation gestures.
- Widgets: Use of Widgets we provide whatever its related widget is in making the layout, in the same way, everything in Flutter is a widget.
- Material & Cupertino: Material and Cupertino widgets are used to create layouts and convert the design of iOS.
=> Engine: Flutter’s engine is written mostly C/C++. It provides low-level implementations of Flutter’s core API, including graphics, text layout, plugin architecture, file, and network I/O, accessibility support, and the dart runtime compile toolchain. responsible for running the compiled dart code on the engine’s device with the help of dart runtime.
=> Embedder:
Flutter Embedder provides the entry point for a platform-specific Flutter app. It receives a thread for the Flutter UI and it also initializes the Flutter engine. Using embedder, we can integrate Flutter’s code into the existing application as a module. Maybe the code of the ambassador is written in a language that is suitable for the platform.
For Example:
Embedder Java and C++ for Android, Embedder Objective-C/Objective-C++ for iOS and macOS, and K++ for Windows and Linux.
Let’s go through this rendering stepwise manner:
- Now our application calls the setState() method in the iconButton.onPressed() callback.
- Flutter then finds that the state value inside it is completely updated and needs to be recreated.
- New Widget Widget Tree replaces the old one after the update
After updating the New Widget widget tree replaces the old one and then renders the new one.
Rendering Pipeline(User Input):
It describes the rendering pipeline that the Flutter rendering engine takes when rendering objects. How the data flows through the system is shown in a diagram.
- Animation: In Flutter Animation, Flutter first starts an animation ticker and then stops the Flutter rendering process as we scroll down the list of any item to move the list of items for such a scenario. We can control this by animation tricker. and determines the time when any element is moved.
- Build: The build method builds the widget tree, taking into account the different configurations of the widget while building it, this means how the widget will look on our screen Widgets handle the same configuration that is applied to the screen.
- Layout: As soon as our widget is built, it starts thinking about the process of layout, it is a way to efficiently determine the part of the important widgets within the UI framework. Has the ability to determine the size and position of the layout before displaying it on the screen The render tree creates a base class for each that defines an abstract model for the layout
Widget build(BuildContext context) {
return Container(
child: Row(
children: List<Widget>[
IconButton(
icon: Icons.add,
onPressed: () {
setState(() {
this.value++;
});
}),
Text("Qty: ${this.value}")
],
)
);
}- Paint: Flutter gets an idea of the constraints of all the widgets then it can paint the entire widget to make sure there are conflicts.
- Composting: In this step, we will see that Composting Flutter displays the actual widget coordinates on the screen. There are many reasons that keep it apart from painting. Instead of building up your entire list when someone scrolls or closes it on the new screen, Flutter can pre-draw it and plug it in where they need to go
How to run flutter code runs on the device:
Below is a simplistic representation of how the dart code runs on the device.
- Before the code is run in Dart, first of all, the code of Dart is compiled into the Arm library code.
- After this, the compiled code is embedded in the APK or IPA file.
- Now when we open the app flutter embedder code is started and it starts the app.
Conclusion:
In this article, I have explained an Under The Hood Rendering in a flutter, which you can modify and experiment with according to your own, this little introduction was from the Under The Hood Rendering.
I hope this blog will provide you with sufficient information on Trying up the Under The Hood Rendering in your flutter project. We showed you the Explore Under The Hood Rendering and worked on it in your flutter applications, So please try it.
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