Flutter ​

var str='this is var';

String str='this is var';

int str=123;

import "dart:core";

void main() {
  const a=[2];
  const b=[2];
  print(identical(a,b)); //true 共享存储空间

  const c=[2];
  const d=[3];
  print(identical(c,d)); //false  不共享存储空间
}

//常量构造函数
class Container{
  final int width;
  final int height;
  const Container({required this.width,required this.height});
}

void main(){

  var c1=Container(width: 100,height: 100);
  var c2=Container(width: 100,height: 100);
  print(identical(c1, c2)); //false

  
  var c3=const Container(width: 100,height: 100);
  var c4=const Container(width: 100,height: 100);
  print(identical(c3, c4)); //true


  var c5=const Container(width: 100,height: 110);
  var c6=const Container(width: 120,height: 100);
  print(identical(c5, c6)); //false
  
}
// 实例化常量构造函数的时候，多个地方创建这个对象，如果传入的值相同，只会保留一个对象。

list.forEach((value)=>{
  print(value)
});
// 简写
list.forEach((value)=>print(value));

//最新版本的dart中需要初始化不可为null的实例字段，如果不初始化的话需要在属性前面加上late
class Person{
  late String name;
  late int age; 
  //默认构造函数的简写
  Person(this.name,this.age);
  Person.now() {
    print('我是命名构造函数');
  }
  Person.setInfo(String name, int age) {
    this.name = name;
    this.age = age;
  }
  void printInfo(){   
    print("${this.name}----${this.age}");
  }
}

void main() {
  var d=new DateTime.now();   //实例化DateTime调用它的命名构造函数
  print(d);

  Person p1=new Person('张三', 20);   //默认实例化类的时候调用的是 默认构造函数

  Person p2=new Person.now();   //命名构造函数

  Person p3 = new Person.setInfo('李四', 30);   //指定参数信息实例化
  p3.printInfo();
}

class Animal{
  late String _name;   //私有属性
  late int age; 
  //默认构造函数的简写
  Animal(this._name,this.age);

  void printInfo(){   
    print("${this._name}----${this.age}");
  }

  String getName(){ 
    return this._name;
  } 
  void _run(){
    print('这是一个私有方法');
  }

  execRun(){
    this._run();  //类里面方法的相互调用
  }
}

void main(){
  Animal a=new Animal('小狗', 3);

  print(a.getName());

  a.execRun();   //间接的调用私有方法
}

class Rect{
  late num height;
  late num width;   
  Rect(this.height,this.width);
  get area{
    return this.height*this.width;
  }
  set areaHeight(value){
    this.height=value;
  }
}

void main(){
  Rect r = new Rect(10,4);
  print("面积:${r.area}");  // get调用直接通过访问属性的方式访问area

  r.areaHeight = 6;   // get调用直接通过访问属性的方式访问area, 6就是传递进去的value参数
  print(r.area);
}

class Rect{
  int height;
  int width;
  Rect():height=2,width=10{    
    print("${this.height}---${this.width}");
  }
  getArea(){
    return this.height*this.width;
  } 
}

void main(){
  Rect r=new Rect();
  print(r.getArea()); 
}

class Person {
  static String name = '张三';
  int age=20;  
  static void show() {
    print(name);
  }
  void printInfo(){  /*非静态方法可以访问静态成员以及非静态成员*/
    print(name);  //访问静态属性
    print(this.age);  //访问非静态属性
    show();   //调用静态方法
  }
  static void printUserInfo(){//静态方法
    print(name);   //静态属性
    show();        //静态方法
    //print(this.age);     //静态方法没法访问非静态的属性
    // this.printInfo();   //静态方法没法访问非静态的方法
    // printInfo();
  }
}

main(){
  print(Person.name);
  Person.show(); 

  Person p=new Person();
  p.printInfo(); 

  Person.printUserInfo();
}

class Person {
  String name;
  num age;
  Person(this.name, this.age);
  void printInfo() {
    print("${this.name}---${this.age}");
  }
}
main() {
  // 条件运算符
  Person pp;
  pp?.printInfo();   //已被最新的dart废弃 了解
  Person p0 = new Person('张三', 20);
  p0?.printInfo();   //已被最新的dart废弃 了解


  // 类型判断
  Person p=new Person('张三', 20);
  if(p is Person){
      p.name="李四";
  }
  p.printInfo();
  print(p is Object);


  // 类型转换
  var p2;
  p2='';
  p2=new Person('张三1', 20);
  p2.printInfo();
  (p2 as Person).printInfo();

  // 级联操作
  Person p1 = new Person('张三1', 20);
  p1.printInfo();
  p1
    ..name = "李四"
    ..age = 30
    ..printInfo();
}

class Person {
  String name;
  num age;
  String sex;
  Person(this.name,this.age);
  void printInfo() {
    print("${this.name}---${this.age}");  
  }
  work(){
    print("${this.name}在工作...");
  }
}
class Web extends Person{
  Web(String name, num age, String sex) : super(name, age){    
  }
  void run() {
    print("${this.name}---${this.age}---${this.sex}");
    super.work(); // 调用父类中的方法
  }
  @override
  work(){ // 覆写父类方法
    print("${this.name}的工作是写代码");
  }
}

main(){
  Web w = new Web('张三', 12, '男');
  w.printInfo();
  w.run();
  w.work();
}

abstract class Animal{
  eat();  //抽象方法，子类必须实现它
  run();  //抽象方法，子类必须实现它
  printInfo(){
    print('我是一个抽象类里面的普通方法');
  }
}

class Dog extends Animal{
  @override
  eat() {
     print('小狗在吃骨头');
  }

  @override
  run() {
    // TODO: implement run
    print('小狗在跑');
  }  
}

class Cat extends Animal{
  @override
  eat() {
    // TODO: implement eat
    print('小猫在吃老鼠');
  }

  @override
  run() {
    // TODO: implement run
    print('小猫在跑');
  }
}

main(){
  Dog d=new Dog();
  d.eat();
  d.printInfo();

  Cat c=new Cat();
  c.eat();
  c.printInfo();

  // Animal a=new Animal();   //抽象类没法直接被实例化，会报错。
}

abstract class Db{   //当做接口   接口：就是约定 、规范
    late String uri;      //数据库的链接地址
    add(String data);
    save();
    delete();
}

class Mysql implements Db{
  @override
  String uri;

  Mysql(this.uri);

  @override
  add(data) {
    // TODO: implement add
    print('这是mysql的add方法'+data);
  }

  @override
  delete() {
    // TODO: implement delete
    return null;
  }

  @override
  save() {
    // TODO: implement save
    return null;
  }
  remove(){
      
  }
}

class MsSql implements Db{
  @override
  late String uri;
  @override
  add(String data) {
    print('这是mssql的add方法'+data);
  }

  @override
  delete() {
    // TODO: implement delete
    return null;
  }

  @override
  save() {
    // TODO: implement save
    return null;
  }
}

main() {
  Mysql mysql = new Mysql('xxxxxx');

  mysql.add('1243214');
}

abstract class A{
  late String name;
  printA();
}

abstract class B{
  printB();
}

class C implements A,B{  
  @override
  late String name;

  @override
  printA() {
    print('printA');
  }
  @override
  printB() {
    print('printB');
  }
}

void main(){
  C c=new C();
  c.printA();
}

// 传的是什么类型就返回什么类型
getData<T>(T value){
  return value;
}

// 把下面类转换成泛型类，要求MyList里面可以增加int类型的数据，也可以增加String类型的数据。但是每次调用增加的类型要统一
class MyList<T> {
  List list = <T>[];
  void add(T value) {
    this.list.add(value);
  }

  List getList() {
    return list;
  }
}
main() {
  List list2 = new List<int>.filled(2, 0);
  list2[0] = 12;
  list2[1] = 13;
  print(list2);
}

abstract class Cache<T> {
  getByKey(String key);
  void setByKey(String key, T value);
}

class FileCache<T> implements Cache<T> {
  @override
  getByKey(String key) {
    return null;
  }
  @override
  void setByKey(String key, T value) {
    print("我是文件缓存 把key=${key}  value=${value}的数据写入到了文件中");
  }
}

class MemoryCache<T> implements Cache<T> {
  @override
  getByKey(String key) {
    return null;
  }
  @override
  void setByKey(String key, T value) {
    print("我是内存缓存 把key=${key}  value=${value} -写入到了内存中");
  }
}

void main() {
  MemoryCache m = new MemoryCache<Map>();
  m.setByKey('index', {"name": "张三", "age": 20});
}

import 'lib/xxx.dart';

import 'dart:math';    
import 'dart:io'; 
import 'dart:convert';

import 'package:http/http.dart' as http;
import 'package:date_format/date_format.dart';

import 'lib/Person2.dart' as lib;

String? getData(apiUrl){  // String? 表示字符串返回值可以为空
  if(apiUrl!=null){
    return "this is server data";
  }
  return null;
}

void printLength(String? str){  // String？ 表示字符串参数可为空
  try {
    print(str!.length); // str! 告诉编译器str不为空，若传入参数为空会抛出异常执行catch里面的代码
  } catch (e) {
    print("str is null"); 
  }
}

late String name;

void main() {
  name = 'John'; // 在使用之前进行延迟初始化

  print(name); // 输出: John
}

class Person {
  final String name;
  final int age;

  Person({required this.name, required this.age});
}

void main() {
  var person = Person(name: 'John', age: 25); // 必须提供两个参数
  print(person.name); // 输出: John
  print(person.age); // 输出: 25

  // 错误示例：未提供必需的参数
  var invalidPerson = Person(); // 编译错误！必须提供 name 和 age 参数
}

void main(){
runApp(MyApp());
}
//也可以简写
void main()=>runApp(MyApp());

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        appBarTheme: const AppBarTheme(
          centerTitle: true,
        )
      ),
      initialRoute: "/",
      onGenerateRoute: onGenerateRoute,
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: Center(
        child: Text('Welcome to my app!'),
      ),
    );
  }
}

// main.dart
import 'package:flutter/material.dart';
import 'pages/index_page.dart';

void main(){
  WidgetsFlutterBinding.ensureInitialized();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: '百姓生活',
      theme: ThemeData(
        primarySwatch: Colors.pink,
      ),
      home: const IndexPage()
    );
  }
}

// index.dart
import 'package:flutter/material.dart';
import 'home_page.dart';
import 'category_page.dart';
import 'my_page.dart';
import 'cart_page.dart';
import 'message_page.dart';

class IndexPage extends StatefulWidget {
  const IndexPage({super.key});

  @override
  State<IndexPage> createState() => _IndexPageState();
}

class _IndexPageState extends State<IndexPage> {
  final List<BottomNavigationBarItem> bottomTabs = [
    const BottomNavigationBarItem(
      icon: Icon(Icons.home),
      label: '首页',
    ),
    const BottomNavigationBarItem(
      icon: Icon(Icons.search),
      label: '分类',
    ),
    const BottomNavigationBarItem(
      icon: Icon(Icons.message),
      label: '消息',
    ),
    const BottomNavigationBarItem(
      icon: Icon(Icons.shopping_cart),
      label: '购物车',
    ),
    const BottomNavigationBarItem(
      icon: Icon(Icons.account_circle),
      label: '我的',
    ),
  ];

  int currentIndex = 0;
  // ignore: prefer_typing_uninitialized_variables
  var currentPage;

  @override
  void initState() {
    currentPage = pages[currentIndex];
    super.initState();
    
  }

  final List<Widget> pages = [
    const HomePage(),
    const CategoryPage(),
    const MessagePage(),
    const CartPage(),
    const MyPage(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color.fromRGBO(240, 240, 240, 1),
      bottomNavigationBar: BottomNavigationBar(
        type: BottomNavigationBarType.fixed,
        currentIndex: currentIndex,
        items: bottomTabs,
        onTap: (index){
          setState(() {
            currentIndex = index;
            currentPage = pages[currentIndex];
          });
        },
      ),
      body: currentPage,
    );
  }
}

// home_page.dart
import 'package:flutter/material.dart';

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Home'),
      ),
      body: Container(),
    );
  }
}

// category_page.dart
import 'package:flutter/material.dart';

class CategoryPage extends StatefulWidget {
  const CategoryPage({super.key});

  @override
  State<CategoryPage> createState() => _CategoryPageState();
}

class _CategoryPageState extends State<CategoryPage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Category'),
      ),
      body: Container(),
    );
  }
}

// message_page.dart
import 'package:flutter/material.dart';

class MessagePage extends StatelessWidget {
  const MessagePage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Message'),
      ),
      body: Container(),
    );
  }
}

// cart_page.dart
import 'package:flutter/material.dart';

class CartPage extends StatefulWidget {
  const CartPage({super.key});

  @override
  State<CartPage> createState() => _CartPageState();
}

class _CartPageState extends State<CartPage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Cart'),
      ),
      body: Container(),
    );
  }
}

// my_page.dart
import 'package:flutter/material.dart';

class MyPage extends StatefulWidget {
  const MyPage({super.key});

  @override
  State<MyPage> createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('My'),
      ),
      body: Container(),
    );
  }
}

// 修改index_page.dart中的Scaffold
Scaffold(
  backgroundColor: const Color.fromRGBO(240, 240, 240, 1),
  bottomNavigationBar: BottomNavigationBar(
    backgroundColor: Color(0xffeeeeee),
    type: BottomNavigationBarType.fixed,  //如果底部有4个或者4个以上的菜单的时候就需要配置这个参数
    currentIndex: currentIndex,
    items: bottomTabs,
    onTap: (index) {
      setState(() {
        currentIndex = index;
        currentPage = pages[currentIndex];
      });
    },
  ),
  body: currentPage,
  floatingActionButton: Container(
    height: 60,
    width: 60,
    padding: const EdgeInsets.all(5),
    margin: const EdgeInsets.only(top: 0),
    decoration: BoxDecoration(
        color: Colors.white, borderRadius: BorderRadius.circular(30)),
    child: FloatingActionButton(
      // backgroundColor: currentPage == 2 ? Colors.red : Colors.blue,
      onPressed: () {
        setState(() {
          currentIndex = 2;
          currentPage = pages[currentIndex];
        });
      },
      child: const Icon(Icons.add),
    ),
  ),
  floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
);

Scaffold(
  appBar: AppBar(
    title: Text("Flutter App"),
  ),
  drawer: Drawer(
    child: Text('左侧边栏'),
  ),
  endDrawer: Drawer(
    child: Text('右侧侧边栏'),
  ),
);

drawer: Drawer(
  child: Column(
    children: [
      Row(
        children: [
          Expanded(
              flex: 1,
              child: DrawerHeader(
                decoration: const BoxDecoration(
                    // color: Colors.yellow,
                    image: DecorationImage(
                        image: NetworkImage(
                            "https://www.itying.com/images/flutter/2.png"),
                        fit: BoxFit.cover)),
                child: Column(
                  children: const [
                    ListTile(
                      leading: CircleAvatar(
                        backgroundImage:NetworkImage("https://www.itying.com/images/flutter/3.png")                             
                      ),
                      title: Text("张三",style: TextStyle(
                        color: Colors.red
                      )),
                    ),
                    ListTile(
                      title: Text("邮箱：xxxx@qq.com"),
                    )
                  ],
                ),
              ))
        ],
      ),
      const ListTile(
        leading: CircleAvatar(
          child: Icon(Icons.people),
        ),
        title: Text("个人中心"),
      ),
      const Divider(),
      const ListTile(
        leading: CircleAvatar(
          child: Icon(Icons.settings),
        ),
        title: Text("系统设置"),
      ),
      Divider(),
    ],
  ),
),

drawer: Drawer(
  child: Column(
    children: [
      Row(
        children: [
          Expanded(
              flex: 1,
              child: UserAccountsDrawerHeader(
                accountName: const Text("Oh Shit"),
                accountEmail: const Text("shit@qq.com"),
                otherAccountsPictures: [
                  Image.network(
                      "https://www.itying.com/images/flutter/1.png"),
                  Image.network(
                      "https://www.itying.com/images/flutter/2.png"),
                  Image.network(
                      "https://www.itying.com/images/flutter/3.png"),
                ],
                currentAccountPicture: const CircleAvatar(
                    backgroundImage: NetworkImage(
                        "https://www.itying.com/images/flutter/3.png")),
                decoration: const BoxDecoration(
                    image: DecorationImage(
                        fit: BoxFit.cover,
                        image: NetworkImage(
                            "https://www.itying.com/images/flutter/2.png"))),
              ))
        ],
      ),
      const ListTile(
        leading: CircleAvatar(
          child: Icon(Icons.people),
        ),
        title: Text("个人中心"),
      ),
      const Divider(),
      const ListTile(
        leading: CircleAvatar(
          child: Icon(Icons.settings),
        ),
        title: Text("系统设置"),
      ),
      const Divider(),
    ],
  ),
),

import 'package:flutter/material.dart';

class MyPage extends StatefulWidget {
  const MyPage({Key? key}) : super(key: key);

  @override
  State<MyPage> createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> with SingleTickerProviderStateMixin {
  late TabController _tabController;

  //生命周期函数:当组件初始化的时候就会触发
  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 9, vsync: this);
  }

  List<String> list = [];
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
            leading: IconButton(
              //左侧的按钮图标
              icon: const Icon(Icons.menu),
              onPressed: () {
                print("左侧的按钮图标");
              },
            ),
            backgroundColor: Colors.red, //导航背景颜色
            title: const Text("Flutter App"),
            actions: [
              //右侧的按钮图标
              IconButton(
                icon: const Icon(Icons.search),
                onPressed: () {
                  print("搜索图标");
                },
              ),
              IconButton(
                icon: const Icon(Icons.more_horiz),
                onPressed: () {
                  print("更多");
                },
              )
            ],
            bottom: TabBar(
                isScrollable: true,
                indicatorColor: Colors.white,
                indicatorWeight: 2,
                indicatorPadding: const EdgeInsets.all(5),
                // indicatorSize:TabBarIndicatorSize.label,
                labelColor: Colors.yellow,
                unselectedLabelColor: Colors.white,
                labelStyle: const TextStyle(fontSize: 14),
                unselectedLabelStyle: const TextStyle(fontSize: 12),
                indicator: BoxDecoration(
                    color: Colors.blue,
                    borderRadius: BorderRadius.circular(10)),
                controller: _tabController, //注意：配置controller需要去掉TabBar上面的const
                tabs: const [
                  Tab(
                    child: Text("关注"),
                  ),
                  Tab(
                    child: Text("热门"),
                  ),
                  Tab(
                    child: Text("视频"),
                  ),
                  Tab(
                    child: Text("关注"),
                  ),
                  Tab(
                    child: Text("热门"),
                  ),
                  Tab(
                    child: Text("视频"),
                  ),
                  Tab(
                    child: Text("关注"),
                  ),
                  Tab(
                    child: Text("热门"),
                  ),
                  Tab(
                    child: Text("视频"),
                  ),
                ])),
        body: TabBarView(controller: _tabController, children: [
          const Text("我是关注"),
          const Text("我是关注"),
          const Text("我是关注"),
          const Text("我是关注"),
          const Text("我是关注"),
          const Text("我是关注"),
          const Text("我是关注"),
          ListView(
            children: const [
              ListTile(
                title: Text("我是热门列表"),
              ),
              ListTile(
                title: Text("我是热门列表"),
              ),
              ListTile(
                title: Text("我是热门列表"),
              ),
              ListTile(
                title: Text("我是热门列表"),
              ),
              ListTile(
                title: Text("我是热门列表"),
              ),
              ListTile(
                title: Text("我是热门列表"),
              ),
              ListTile(
                title: Text("我是热门列表"),
              ),
            ],
          ),
          ListView(
            children: const [
              ListTile(
                title: Text("我是视频列表"),
              )
            ],
          )
        ]));
  }
}

Scaffold(
  appBar: PreferredSize(
    preferredSize: Size.fromHeight(50),
    child: AppBar(
      ....
    )
  ),
  body: Test(),
)

import 'package:flutter/material.dart';

class KeepAliveWrapper extends StatefulWidget {
  const KeepAliveWrapper(
      {Key? key, @required this.child, this.keepAlive = true})
      : super(key: key);

  final Widget? child;
  final bool keepAlive;

  @override
  State<KeepAliveWrapper> createState() => _KeepAliveWrapperState();
}

class _KeepAliveWrapperState extends State<KeepAliveWrapper>
    with AutomaticKeepAliveClientMixin {
  @override
  Widget build(BuildContext context) {
    return widget.child!;
  }

  @override
  bool get wantKeepAlive => widget.keepAlive;

  @override
  void didUpdateWidget(covariant KeepAliveWrapper oldWidget) {
    if (oldWidget.keepAlive != widget.keepAlive) {
      // keepAlive 状态需要更新，实现在 AutomaticKeepAliveClientMixin 中
      updateKeepAlive();
    }
    super.didUpdateWidget(oldWidget);
  }
}

void initState() {
  super.initState();
  _tabController = TabController(length: 8, vsync: this);
  //监听_tabController的改变事件
  _tabController.addListener(() {
    if (_tabController.animation!.value==_tabController.index){
      print(_tabController.index); //获取点击或滑动页面的索引值
    }
  });
}

import 'package:flutter/material.dart';
void main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(title: const Text("你好Flutter")),
      body: const MyApp(),
    ),
  ));
}
// 代码块 statelessW
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Container(
        alignment: Alignment.center,
        height: 200,
        width: 200,
        decoration: BoxDecoration(
          color: Colors.yellow,
          gradient: const LinearGradient(
            //LinearGradient 背景线性渐变 RadialGradient径向渐变
            colors: [Colors.red, Colors.orange],
          ),
          boxShadow:const [
            //卡片阴影
            BoxShadow(
              color: Colors.blue,
              offset: Offset(2.0, 2.0),
              blurRadius: 10.0,
            )
          ],
          border: Border.all(
            color: Colors.black,
            width: 1
          )
        ),
        transform:Matrix4.rotationZ(.2),
        child: const Text(
          "你好Flutter",
          style: TextStyle(fontSize: 20),
        ),
      ),
    );
  }
}

import 'package:flutter/material.dart';
void main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(title: const Text("你好Flutter")),
      body: const MyApp(),
    ),
  ));
}
// 代码块 statelessW
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
  return Center(
    child: Container(
      alignment: Alignment.center,
      height: 200,
      width: 200,
      decoration: BoxDecoration(
        color: Colors.yellow,
        gradient: const LinearGradient(
          //LinearGradient 背景线性渐变 RadialGradient径向渐变
          colors: [Colors.red, Colors.orange],
        ),
        boxShadow: const [
          //卡片阴影
          BoxShadow(
            color: Colors.blue,
            offset: Offset(2.0, 2.0),
            blurRadius: 10.0,
          )
        ],
        border: Border.all(color: Colors.black, width: 1)),
        transform: Matrix4.rotationZ(.2),
        child: const Text(
          '我是傻批',
          textAlign: TextAlign.left,
          overflow: TextOverflow.ellipsis,
          // overflow:TextOverflow.fade ,
          maxLines: 2,
          textScaleFactor: 1.8,
          style: TextStyle(
            fontSize: 16.0,
            color: Colors.black,
            // color:Color.fromARGB(a, r, g, b)
            fontWeight: FontWeight.w800,
            fontStyle: FontStyle.italic,
            decoration: TextDecoration.lineThrough,
            decorationColor: Colors.white,
            decorationStyle: TextDecorationStyle.dashed,
            letterSpacing: 5.0
          )
        ),
      ),
    );
  }
}

// 加载远程图片
Image.network(
  "https://www.itying.com/themes/itying/images/ionic4.png",
  fit: BoxFit.cover,
)