[flutter] 用InheritedWidget简单实现数据

一直使用provider做状态管理，看了下源码，简单化的做个状态管理更新，可以适用于Theme切换，货币切换，语言切换等

效果

Screen_recording_20240830_142539.gif

创建一个StateContainer文件，保存你所需要修改的所有数据

import 'package:flutter/material.dart';
import 'package:test/theme/themes.dart';

class _InheritedStateContainer extends InheritedWidget {
  final StateContainerState data;

  const _InheritedStateContainer(
      {Key? key, required this.data, required Widget child})
      : super(key: key, child: child);

  @override
  bool updateShouldNotify(covariant InheritedWidget oldWidget) {
    // TODO: implement updateShouldNotify
    return true;
  }
}

class StateContainer extends StatefulWidget {
  final Widget child;
  const StateContainer({super.key, required this.child});

  static StateContainerState of(BuildContext context) => context.dependOnInheritedWidgetOfExactType<_InheritedStateContainer>()!.data;

  @override
  State<StatefulWidget> createState() => StateContainerState();
}

class StateContainerState extends State<StateContainer> {

  int count = 0;
  updateCount(int cou){
    count = cou;
    setState(() {

    });
  }

  BaseTheme curTheme = LightTheme();
  updateTheme(bool isNight){
    curTheme = isNight ? NightTheme() : LightTheme();
    setState(() {

    });
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
      return _InheritedStateContainer(data: this, child: widget.child);
  }
}

创建theme值管理文件

import 'package:flutter/material.dart';

abstract class BaseTheme{

  bool isDark = false;
  Color? backGroundColor;
  Color? titleColor;
}

class LightTheme extends BaseTheme{

  @override
  Color? backGroundColor = Colors.black;

  @override
  // TODO: implement titleColor
  Color? get titleColor => Colors.white;
}

class NightTheme extends BaseTheme{
  @override
  Color? backGroundColor = Colors.blue;

  @override
  // TODO: implement titleColor
  Color? get titleColor => Colors.black;
}

具体的页面

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:test/theme/appstate_container.dart';

class ThemeTestPage extends StatefulWidget {
  const ThemeTestPage({super.key});
  @override
  State<StatefulWidget> createState() {
    return ThemeTestPageState();
  }
}

class ThemeTestPageState extends State<ThemeTestPage> {
  int index = 0;
  late Timer _time;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    _time = Timer.periodic(const Duration(seconds: 3), (timer) {
      StateContainer.of(context).updateCount(index++);
      StateContainer.of(context).updateTheme(index % 2 == 0);
    });
  }

  @override
  Widget build(BuildContext context) {
    final count = StateContainer.of(context).count;

    // TODO: implement build
    return Scaffold(
      appBar: AppBar(),
      body: Container(
        color: StateContainer.of(context).curTheme.backGroundColor,
        child: Center(
          child: Text(
            '当前数字$count',
            style: TextStyle(
                color: StateContainer.of(context).curTheme.titleColor,
                fontSize: 16),
          ),
        ),
      ),
    );
  }

  @override
  void dispose() {
    super.dispose();
    _time.cancel();
  }
}