You can see the following hierarchy: root > MyApp > MaterialApp > MyHomePage > Scaffold > Center, column, text, text, AppBar, Text, FloatinActionButton, Icon
[root]: This is the entry point for the Flutter application. Typically, in the main.dart file, you’ll find:
Follow the instructions to install Flutter with Visual Studio Code
main.dart:
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// TRY THIS: Try changing the color here to a specific color (to
// Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
// change color while the other colors stay the same.
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
//
// TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
// action in the IDE, or press "p" in the console), to see the
// wireframe for each widget.
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text('You have pushed the button this many times:'),
Text(
'$_counter',
style: Theme.of(context).textTheme.headlineMedium,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
Use the «flutter doctor» command to check if both the installation and configuration have been done correctly.
Use the «flutter doctor» command to check if both the installation and configuration have been done correctly.
Sometimes we are only interested in a few properties from all the ones sent to us.
App.jsx
import { useState } from 'react'
import reactLogo from './assets/react.svg'
import viteLogo from '/vite.svg'
import './App.css'
import HelloWorld from './components/HelloWorld'
const car ={
color: "blue",
wheels:4,
engine: "diesel"
};
function App() {
return (
<>
<h1>App component</h1>
<HelloWorld color={car.color} wheels={car.wheels} engine={car.engine}/>
</>
)
}
export default App;
HelloWorld.jsx
function HelloWorld({color, engine}){
return(<>
<h2>Your car has {color} color and {engine} engine</h2>
</>);
}
export default HelloWorld;
Props.children
Another project is created
App.jsx
import './App.css'
import Parents from './components/Parents'
function App() {
return (
<>
<h1>App</h1>
<Parents/>
</>
)
}
export default App
Parents.jsx
import Daughter from "./Daughter";
import Son from "./Son"
const Parents = ()=>{
return(
<>
<Son>
<h1> I am your son</h1>
</Son>
<Daughter>
<h1> I am your daughter</h1>
</Daughter>
</>
);
}
export default Parents;
