flutter第九天------组件通信

OK呀,今天开始学组件通信,我没有听说过这个概念,所以先了解一下吧

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构造函数传递(父传子)

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子组件属性如果没有初始值，需要在构造函数中用required来接收属性

无状态组件子组件

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import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "终末地AI群聊",
      home: Scaffold(
        appBar: AppBar(centerTitle: true, title: Text("终末地AI群聊")),
        body: Container(
          alignment: Alignment.center,
          child: Column(
            children: [
              Text(
                "终末地AI群聊",
                style: TextStyle(fontSize: 20, color: Colors.red),
              ),
              Child(name: "终末地AI群聊"),
            ],
          ),
        ),
        bottomNavigationBar: BottomAppBar(
          child: Container(
            height: 50,
            child: Center(child: Text("Copyright © 2024 终末地AI群聊")),
          ),
        ),
      ),
    );
  }
}

class Child extends StatelessWidget {
  final String name;
  const Child({super.key, required this.name}); //使用命名参数来传递name参数

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text(
        name,
        style: TextStyle(fontSize: 20, color: Colors.cyanAccent),
      ),
    );
  }
}

​

有状态组件子组件

DART已复制

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import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "终末地AI群聊",
      home: Scaffold(
        appBar: AppBar(centerTitle: true, title: Text("终末地AI群聊")),
        body: Container(
          alignment: Alignment.center,
          child: Column(
            children: [
              Text(
                "终末地AI群聊",
                style: TextStyle(fontSize: 20, color: Colors.blueAccent),
              ),
              Child(message: "Hello World"), // 传递参数给子组件
            ],
          ),
        ),
        bottomNavigationBar: BottomAppBar(
          child: Container(
            height: 50,
            child: Center(child: Text("Copyright © 2024 终末地AI群聊")),
          ),
        ),
      ),
    );
  }
}

class Child extends StatefulWidget {
  final String message; // 定义一个参数，用于接收父组件传递的数据
  const Child({super.key, required this.message}); // 通过构造函数接收父组件传递的参数

  @override
  State<Child> createState() => _ChildState();
}

class _ChildState extends State<Child> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text(
        "子组件${widget.message}", // 通过 widget.message 获取父组件传递的参数
        style: TextStyle(fontSize: 20, color: Colors.red),
      ),
    );
  }
}

这里可以尝试用List来实现子组件的生成

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import 'package:flutter/material.dart';

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

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

  @override
  State<MainPage> createState() => _MainPageState();
}

class _MainPageState extends State<MainPage> {
  List<String> _list = [
    //用List来列举数据
    "钻石剑",
    "下届合金剑",
    "木剑",
    "石剑",
    "铁剑",
    "金剑",
    "铜剑",
    "三叉戟",
    "弓箭",
  ];
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "终末地AI群聊",
      home: GridView.count(
        padding: EdgeInsets.all(10), //内边距
        crossAxisCount: 2, //每行显示2个
        mainAxisSpacing: 10, //主轴间距
        crossAxisSpacing: 10, //交叉轴间距
        //生成List的长度个Child
        children: List.generate(_list.length, (int index) {
          return Child(weaponname: _list[index]);
        }),
      ),
    );
  }
}

class Child extends StatefulWidget {
  final String weaponname;
  const Child({super.key, required this.weaponname});

  @override
  State<Child> createState() => _ChildState();
}

class _ChildState extends State<Child> {
  @override
  Widget build(BuildContext context) {
    return Container(
      alignment: Alignment.center, //子组件居中对齐
      decoration: BoxDecoration(
        border: Border.all(color: Colors.black, width: 5),
        color: Colors.blueGrey,
        borderRadius: BorderRadius.all(Radius.circular(40)),
      ), //边框和背景颜色
      child: Text(
        widget.weaponname,
        style: TextStyle(
          fontSize: 20,
          color: Colors.white,
          fontWeight: FontWeight.bold,
        ),
      ), //子组件显示的文本
    );
  }
}

回调函数传递(子传父)

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import 'package:flutter/material.dart';

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

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

  @override
  State<MainPage> createState() => _MainPageState();
}

class _MainPageState extends State<MainPage> {
  List<String> _list = [
    //用List来列举数据
    "钻石剑",
    "下届合金剑",
    "木剑",
    "石剑",
    "铁剑",
    "金剑",
    "铜剑",
    "三叉戟",
    "弓箭",
  ];
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "终末地AI群聊",
      home: GridView.count(
        padding: EdgeInsets.all(10), //内边距
        crossAxisCount: 2, //每行显示2个
        mainAxisSpacing: 10, //主轴间距
        crossAxisSpacing: 10, //交叉轴间距
        //生成List的长度个Child
        children: List.generate(_list.length, (int index) {
          return Child(
            weaponname: _list[index],
            index: index,
            onDelete: (int i) {
              //删除回调函数
              setState(() {
                _list.removeAt(i);
              });
            },
          );
        }),
      ),
    );
  }
}

class Child extends StatefulWidget {
  final String weaponname;
  final int index;
  final Function(int) onDelete; //定义回调函数用于删除操作
  const Child({
    super.key,
    required this.weaponname,
    required this.index,
    required this.onDelete,
  });

  @override
  State<Child> createState() => _ChildState();
}

class _ChildState extends State<Child> {
  @override
  Widget build(BuildContext context) {
    return Stack(
      alignment: Alignment.bottomRight,
      children: [
        Container(
          alignment: Alignment.center, //子组件居中对齐
          decoration: BoxDecoration(
            border: Border.all(color: Colors.black, width: 5),
            color: Colors.blueGrey,
            borderRadius: BorderRadius.all(Radius.circular(40)),
          ), //边框和背景颜色
          child: Text(
            widget.weaponname,
            style: TextStyle(
              fontSize: 20,
              color: Colors.white,
              fontWeight: FontWeight.bold,
            ),
          ), //子组件显示的文本
        ),
        IconButton(
          onPressed: () {
            widget.onDelete(widget.index); //调用回调函数删除当前子组件
          },
          icon: Icon(Icons.delete, color: Colors.cyanAccent, size: 30),
        ), //删除按钮,点击删除子组件
      ],
    );
  }
}