在小部件之外调用setState

Question

我可以从小部件外部调用 setState 吗？我尝试注册子窗口小部件的 setState - 并从外部调用它。它似乎不起作用 - 这是为什么？

import 'package:flutter/material.dart';
import 'package:linkimager/sizes.dart';
import 'package:linkimager/store.dart';

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

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

  @override
  MyAppState createState() => MyAppState();
}

class MyAppState extends State<MyApp> {

  @override
  Widget build(BuildContext context) {
    ScreenSizes.init(MediaQuery.of(context).size);
    int number = 0;
    return MaterialApp(
      home: Scaffold(
        body: ChildWidget(number),
        floatingActionButton: FloatingActionButton(
          onPressed: () {
            number++;
            Renderer.setStateChild();
          },
          child: const Icon(Icons.add),
        ),
      ),
    );
  }
}

class ChildWidget extends StatefulWidget {
  final int number;

  const ChildWidget(this.number, {super.key});

  @override
  ChildWidgetState createState() => ChildWidgetState();
}

class ChildWidgetState extends State<ChildWidget> {

  @override
  void initState() {
    print("registered setStateChild");
    Renderer.setStateChild = () => setState;
    super.initState();
  }

  @override
  Widget build(BuildContext context) {

    return Center(child: Text(widget.number.toString()));
  }
}

class Renderer {
  static Function setStateChild = () {}; 
}

我不是在寻找状态管理工具，而是想了解是什么阻碍了外部渲染

Answer 1

我为你做了这个例子：

void main() {
  
  Renderer.setStateChild = () => setState;
  
  Renderer.setStateChild()();
}

void setState(){
  
  for (int i = 0; i < 10; i++) {
    print('hello ${i + 1}');
  }
}


class Renderer {
  static Function setStateChild = () {}; 
}

您的问题可能是 setStateChild 返回一个函数，因此您可能错过了额外的调用“Renderer.setStateChild()();”