Argument type 'Widget' can't be assigned to the parameter type 'PreferredSizeWid-CodePudding

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?'.'

CodePudding user response：

Try to wrap AppBar widget with PreferredSize Widget.

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