The method 'useEffect' isn't defined for the type-CodePudding

I'm new to flutter and I want to implement the When I remove the useEffect hook out of the build function and put it directly in the class I got error 'useEffect' must have a method body because '_MarketRunnerChartState' isn't abstract. I'm used to work with React, but right now with flutter I can't figure out how to implement that hook.

How am I supposed to do this ?

CodePudding user response：

try add

import 'package:flutter_hooks/flutter_hooks.dart';

on top of your class file

CodePudding user response：

import flutter hooks

import 'package:flutter_hooks/flutter_hooks.dart';

class MarketRunnerChart extends StatefulWidget {
    const MarketRunnerChart({Key? key}) : super(key: key);

    @override
    State<MarketRunnerChart> createState() => _MarketRunnerChartState();
}

class _MarketRunnerChartState extends State<MarketRunnerChart> {
    useEffect(() {
        print('your log');
    }, []);

    @override
    Widget build(BuildContext context) {

        return Text("Some text");
    }
}

CodePudding user response：

You can follow the doc example, import flutter_hooks, extend the HookWidget.

import 'package:flutter_hooks/flutter_hooks.dart';

class Example extends HookWidget {
  const Example({Key? key, })
      : super(key: key);

  @override
  Widget build(BuildContext context) {
     //your variable/instance like to listen
    useEffect(() {
      log('okok');
    }, [...listenThisInstance...]);
    return Container();
  }
}

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