Argument type 'Widget' can't be assigned to the parameter type 'PreferredSizeWidget?'

Question

Once I tried to add appBar to the feed page it is raising error.

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:wecare_u/constants/Constantcolors.dart';

class FeedHelpers with ChangeNotifier {
ConstantColors constantColors = ConstantColors();
Widget appBar(BuildContext context) {
return AppBar(
  backgroundColor: constantColors.darkColor,
  centerTitle: true,
  actions: [
    IconButton(
        icon: Icon(Icons.camera_enhance_rounded,
            color: constantColors.greenColor),
        onPressed: () {})
  ],
  title: RichText(
    text: TextSpan(
        text: 'Social ',
        style: TextStyle(
          color: constantColors.whiteColor,
          fontWeight: FontWeight.bold,
          fontSize: 20.0,
        ),
        children: <TextSpan>[
          TextSpan(
              text: 'Feed',
              style: TextStyle(
                color: constantColors.blueColor,
                fontWeight: FontWeight.bold,
                fontSize: 20.0,
              ))
        ]),
  ),
  );
  }
  }

Above is my Feed_helpers.dart file which contains the code for the page.

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:wecare_u/Designs/Feed_helpers.dart';

class Feed extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
  appBar: Provider.of<FeedHelpers>(context, listen: false).appBar(context),
  );}}

This is my feed.dart file, When I tried to add appBar in this page it is raising error as 'The argument type 'Widget' can't be assigned to the parameter type 'PreferredSizeWidget?'.'

Answer 1

Try to wrap AppBar widget with PreferredSize Widget.

PreferredSize(
  preferredSize: Size.fromHeight(20.0), // height of appbar
  child:  AppBar(
             ..........
          ),
  ),