What is flutter and How to use it?

 Flutter is an open-source, cross-platform mobile application development framework created by Google. It uses the Dart programming language and provides a fast, expressive and flexible way to build beautiful, high-performance and high-fidelity mobile apps for iOS and Android.

There are several reasons why one might choose to use Flutter over React Native:

1. Performance: Flutter has its own graphics engine, which results in smooth and fast performance, especially for animations and scrolling.
2. Hot Reload: Flutter has a "hot reload" feature that allows developers to quickly make changes and see the results in real-time, making development faster and more efficient.
3. Customization: Flutter has a large number of customizable widgets that allow developers to create beautiful and unique designs.
4. Dart language: Flutter uses the Dart programming language, which has a more concise and efficient syntax than JavaScript, the language used by React Native.
5. Easy to learn: The Dart language and the Flutter framework are both designed to be easy to learn and use, making it a great choice for developers who are new to app development.

how the flutter engine work?

Flutter uses a custom engine called "Flutter Engine" to power its framework. The Flutter Engine provides low-level rendering support using Google's Skia graphics library, which provides the ability to render graphics, animations, and gestures.

The Flutter Engine communicates with the Flutter framework, which is written in Dart programming language, to build the user interface of an app. The Flutter framework provides a collection of customizable widgets, which are the building blocks of a Flutter app's user interface. These widgets are rendered by the Flutter Engine and are composited into a final visual representation of the app.

The Flutter Engine also handles the communication between the framework and the underlying platform, whether it's Android, iOS, or the web. This communication includes sending and receiving touch events, handling gestures, and rendering graphics.

The Flutter Engine works by executing the Dart code in a fast, high-performance manner, which results in smooth and responsive apps. This is achieved by using ahead-of-time (AOT) compilation, where the Dart code is compiled into native code for the platform before the app is run, rather than just-in-time (JIT) compilation, which compiles the code at runtime.

Flutter uses the Dart programming language to build cross-platform applications. The Flutter framework compiles the Dart code into native code that runs on both iOS and Android devices. The Flutter engine provides the framework with a set of low-level services such as rendering, event handling, and access to the device's system APIs. The framework also includes a rich set of pre-designed widgets, which can be combined to create custom user interfaces. This combination of the Dart code, the Flutter engine, and the framework's pre-designed widgets allows for a single codebase that can be used to build applications for multiple platforms with a high level of consistency and performance.

Here's a simple "Hello World" program in Flutter:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Hello World',
      home: Scaffold(
        appBar: AppBar(
          title: Text('Hello World'),
        ),
        body: Center(
          child: Text('Hello World'),
        ),
      ),
    );
  }
}

This program creates a MaterialApp widget, which is the root of the widget tree in Flutter. The MaterialApp widget contains an AppBar and a Scaffold widget. The Scaffold widget contains a title and a body. The body consists of a Center widget that contains the text "Hello World".