SliverAppBar with Rounded Corners at the bottom

sliverAppBarRounded

import 'dart:math';

import 'package:english_words/english_words.dart';
import 'package:flutter/material.dart';

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

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

class _SliverAppBarRoundedState extends State<SliverAppBarRounded> {
  late ScrollController _scrollController;
  static const kExpandedHeight = 200.0;
  final _randomWord = <WordPair>[];
  //Color _appBarColor = AppColors.blackCoffee;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();

    _scrollController = ScrollController()
      ..addListener(() {
        setState(() {});
      });
  }

  bool get _showAppBarTitle {
    return _scrollController.hasClients &&
        _scrollController.offset > kExpandedHeight - kToolbarHeight;
  }


  Widget buildListRow(WordPair pair) {
    return Row(
      children: [
        Padding(
          padding: const EdgeInsets.all(16.0),
          child: Container(
            height: 20,
            width: 20,
            color: Colors.primaries[Random().nextInt(Colors.primaries.length)],
          ),
        ),
        const SizedBox(
          width: 16,
        ),
        Text(
          pair.asCamelCase,
          style: const TextStyle(fontSize: 22.0),
        ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        physics: const BouncingScrollPhysics(
          parent: AlwaysScrollableScrollPhysics(),
        ),
        controller: _scrollController,
        slivers: <Widget>[
          SliverAppBar(
            stretch: true,
            centerTitle: true,
            iconTheme: const IconThemeData(color: Colors.black),
            title: _showAppBarTitle ? const Text('App Bar Title') : null,
            shape: const RoundedRectangleBorder(
              borderRadius: BorderRadius.only(
                bottomLeft: Radius.circular(20.0),
                bottomRight: Radius.circular(20.0),
              ),
            ),
            pinned: true,
            snap: false,
            floating: false,
            expandedHeight: kExpandedHeight,
            flexibleSpace: _showAppBarTitle
                ? null
                : FlexibleSpaceBar(
                    /*titlePadding: const EdgeInsetsDirectional.only(
                        start: 16.0, bottom: 16.0),*/
                    centerTitle: true,
                    title: const Text(
                      'Beach Side',
                      textScaleFactor: 1.0,
                      style: TextStyle(
                          color: Colors.black, fontWeight: FontWeight.bold),
                    ),
                    stretchModes: const <StretchMode>[
                      StretchMode.zoomBackground,
                      StretchMode.blurBackground,
                      StretchMode.fadeTitle,
                    ],
                    // ClipRRect added here for rounded corners
                    background: ClipRRect(
                      borderRadius: const BorderRadius.only(
                        bottomLeft: Radius.circular(20.0),
                        bottomRight: Radius.circular(20.0),
                      ),
                      child: Image.asset(
                        'assets/images/newBeach.jpg',
                        fit: BoxFit.fill,
                      ),
                    ),
                  ),
          ),
          //SliverAppBarOpacity()
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (BuildContext context, int i) {
                if (i.isOdd) {
                  return const Divider();
                }
                final index = i ~/ 2;
                if (index >= _randomWord.length) {
                  _randomWord.addAll(generateWordPairs().take(10));
                }
                return buildListRow(_randomWord[index]);
              },
              //childCount: 20,
            ),
          ),
        ],
      ),
    );
  }
}