Flutter使用provide状态管理器管理界面

先看图，没图说个J8

Provide是Google官方推出的状态管理模式。(Google的亲儿子)
github地址为：https://github.com/google/flutter-provide

使用步骤如下：

1.在pubspec.yaml添加依赖

provide: ^1.0.2

2.创建add.dart文件

import 'package:flutter/material.dart';

class Counter with ChangeNotifier{
  int value = 0;
 //内部方法
  increment(){
    value ++;
    notifyListeners();
  }
}

3.在main.dart中注册provide

import 'package:flutter_shop/provide/add.dart';
import 'package:provide/provide.dart';
void main() {
  var counter = Counter();
  providers
    ..provide(Provider<Counter>.value(counter));
  runApp(ProviderNode(child: MyApp(), providers: providers));
}

3.界面具体调用如下：

import 'package:flutter/material.dart';
import 'package:provide/provide.dart';
import 'add.dart';
class Number extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      margin: EdgeInsets.only(top: 200),
      child: Provide<Counter>(
        builder:(context,child,counter){
          return Text('${counter.value}');
        }
      )
    );
  }
}

class Button extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: RaisedButton(
        onPressed: (){
          Provide.value<Counter>(context).increment();
        },
        child: Text('递增'),),
    );
  }
}