flutter learning route

Flutter is a cross-platform mobile application development framework developed by Google, which can build applications for multiple platforms such as iOS, Android, Web, Mac, Windows and Linux with a single code base. If you want to learn Flutter, here are some steps and examples for your reference:

1. Learn the Dart programming language

Dart is the official programming language of Flutter, so before learning Flutter, you need to learn Dart. Dart is an object-oriented language with many features of modern programming languages, such as asynchronous programming, generics, optional types, etc. Dart's official documentation provides a good learning resource, including basic grammar, object-oriented programming, asynchronous programming, generics, etc.

2. Install Flutter

Before you can start writing Flutter applications, you need to install Flutter and the corresponding tools. Flutter's official documentation provides detailed installation instructions, including installation and configuration methods for various operating systems.

3. Learn the basics of Flutter

Flutter provides a series of Widgets to build application interface. Widgets are the basic building blocks in Flutter that are used to build an app's view hierarchy. Flutter provides many predefined Widgets, such as Text, Button, Image, etc. At the same time, Flutter also allows users to customize Widgets so that they can create their own Widgets according to actual needs.

Here is a simple Flutter app that contains a Text Widget that contains the text "Hello World":

import 'package:flutter/material.dart';

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

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

In the above code, we first import the flutter/material.dart library, which provides many basic widgets required for Flutter application development. Then we define a MyApp class and override the build method, which returns a MaterialApp Widget. MaterialApp is a top-level widget in Flutter, which provides the basic structure of the application, such as application bar, theme and so on. In MaterialApp, we define a Scaffold Widget, which provides the basic layout of the application page, including the application bar, drawer menu, bottom navigation bar, etc. In the body property of the Scaffold, we use a Center Widget, which is used to display its child Widget in the center, which contains a Text Widget, which is used to display the "Hello World" text.

4. Learn advanced knowledge of Flutter

Once you are familiar with the basics of Flutter, you can dive into the advanced knowledge of Flutter, such as animations, charts, network connections, databases, and more. Flutter's official documentation provides a wealth of learning resources, including many useful sample codes and tutorials.

Here's a simple Flutter animation example that uses the AnimatedContainer Widget to create a rectangle with a gradient background color:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
    
    
  @override
  Widget build(BuildContext context) {
    
    
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
    
    
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
    
    
  var _color = Colors.blue;
  var _width = 100.0;
  var _height = 100.0;

  void _changeColor() {
    
    
    setState(() {
    
    
      _color = Colors.redAccent;
      _width = 200.0;
      _height = 200.0;
    });
  }

  @override
  Widget build(BuildContext context) {
    
    
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Animation Example'),
      ),
      body: Center(
        child: GestureDetector(
          onTap: _changeColor,
          child: AnimatedContainer(
            duration: Duration(seconds: 1),
            width: _width,
            height: _height,
            decoration: BoxDecoration(
              color: _color,
              borderRadius: BorderRadius.circular(10.0),
            ),
          ),
        ),
      ),
    );
  }
}

In the above code, we define a MyHomePage class, which inherits from StatefulWidget and rewrites the build method. In the build method, we use the GestureDetector Widget to add a click event that calls the _changeColor method. In the _changeColor method, we use the setState method to update the values ​​of the color, width and height properties. At the same time, in the AnimatedContainer Widget, we specify the duration of the animation, and use the decoration property to set the background color and rounded border.

In short, learning Flutter requires mastering the basic knowledge of the Dart programming language and Flutter, and at the same time learning the advanced knowledge of Flutter in depth. During the learning process, you can get more help and support by consulting official documents, referring to sample codes, or joining the Flutter community.