在构建过程中调用 setState() 或 markNeedsBuild()...失败的断言：第 4134 行 pos 12：“！_debugLocked”：不是真的

Question

Very new to flutter and I get that type error. I build simple meals app .I don't know solution

I add simple Drawer() and in this route then get error. I tried all online solution but never get solution

When I open Drawer suddenly get That type error I don't Know solution.

please give me Solution

import 'package:flutter/material.dart';
import 'package:recipes/screens/filters_screen.dart';

class MainDrawer extends StatelessWidget {
  const MainDrawer({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    Widget buildListTile(String title, IconData icon, Function tapHandler) {
      return ListTile(
          leading: Icon(
            icon,
            size: 26,
          ),
          title: Text(
            title,
            style: TextStyle(
                fontFamily: 'RobotoCondensed',
                fontSize: 24,
                fontWeight: FontWeight.bold),
          ),
          onTap: tapHandler());
    }

    return Drawer(
        child: Column(
      children: [
        Container(
          height: 120,
          width: double.infinity,
          padding: EdgeInsets.all(20),
          alignment: Alignment.centerLeft,
          color: Theme.of(context).accentColor,
          child: Text(
            'Cooking up!',
            style: TextStyle(
                fontWeight: FontWeight.w900,
                fontSize: 30,
                color: Theme.of(context).primaryColor),
          ),
        ),
        SizedBox(
          height: 20,
        ),
        buildListTile('Meals', Icons.restaurant, () {
          Navigator.of(context).pushNamed('/');
        }),
        buildListTile('Filters', Icons.settings, () {
          Navigator.of(context).pushNamed(FilterScreen.routeName);
        }),
      ],
    ));
  }
}

Answer 1

It's because your buildListTile widget rebuilt recursively each time you tapping the menu item. So, try moving your buildListTile method from build method.

your class structure should be something like this:

class MainDrawer extends StatelessWidget {
  const MainDrawer({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    

    return Drawer(
         ....
    );
  }

  Widget buildListTile(String title, IconData icon, Function tapHandler) {
      return ListTile(
         ...
      );
    }
}