Flutter有状态组件使用详解

// ignore_for_file: prefer_const_constructors, prefer_collection_literals, deprecated_member_use, unused_local_variable, must_be_immutable, prefer_const_literals_to_create_immutables

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Flutter Demo'),
        ),
        body: const HomeContent(),
      ),
      theme: ThemeData(
        primarySwatch: Colors.yellow,
      ),
    );
  }
}
//有状态自定义组件有两个类，我们需要返回的写在第二个类中
class HomeContent extends StatefulWidget {
  const HomeContent({Key? key}) : super(key: key);
  @override
  _HomeContentState createState() => _HomeContentState();
}

class _HomeContentState extends State<HomeContent> {
  int count = 0;
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
      children: [
        Chip(
          label: Text("$count"),
        ),
        ElevatedButton(
            onPressed: () {
              setState(() {
                count++;
              });
            },
            child: Text("点击加一"))
      ],
    ),
    );
  }
}