Content over appbar in flutter?

Question

I just want to make UI like content over the appbar, but I couldn't. Here is my code that I got from web. how to make the listview top of appbar and remove the card.

import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: Sample2(),
    ),
  );
}

class Sample2 extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Material(
        child: CustomScrollView(
          slivers: [
            SliverPersistentHeader(
              delegate: MySliverAppBar(expandedHeight: 200),
              pinned: true,
            ),
            SliverList(
              delegate: SliverChildBuilderDelegate(
                (_, index) => ListTile(
                  title: Text("Index: $index"),
                ),
              ),
            )
          ],
        ),
      ),
    );
  }
}

class MySliverAppBar extends SliverPersistentHeaderDelegate {
  final double expandedHeight;

  MySliverAppBar({@required this.expandedHeight});

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return Stack(
      fit: StackFit.expand,
      overflow: Overflow.visible,
      children: [
        Image.network(
          "https://images.pexels.com/photos/396547/pexels-photo-396547.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500",
          fit: BoxFit.cover,
        ),
        Center(
          child: Opacity(
            opacity: shrinkOffset / expandedHeight,
            child: Text(
              "MySliverAppBar",
              style: TextStyle(
                color: Colors.white,
                fontWeight: FontWeight.w700,
                fontSize: 23,
              ),
            ),
          ),
        ),
        Positioned(
          top: expandedHeight / 2 - shrinkOffset,
          left: MediaQuery.of(context).size.width / 4,
          child: Opacity(
            opacity: (1 - shrinkOffset / expandedHeight),
            child: Card(
              elevation: 10,
              child: SizedBox(
                height: expandedHeight,
                width: MediaQuery.of(context).size.width / 2,
                child: FlutterLogo(),
              ),
            ),
          ),
        ),
      ],
    );
  }

  @override
  double get maxExtent => expandedHeight;

  @override
  double get minExtent => kToolbarHeight;

  @override
  bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) => true;
}

Using stack is not the best way I think. May be I am wrong. but I think customScrollView and sliverappbar can do this. but I didn't get any tutorial or youtube videos. Most of the examples are listview below the appbar. I just want content over the appbar at first time, when it scrolls it should go below the appbar.

Answer 1

This will help you to hide appbar on scroll

  @override
      Widget build(BuildContext context) {
        return Scaffold(
          body: NestedScrollView(
            headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
              return <Widget>[
                SliverAppBar(
                  title: Text('Sameple text'),
                  pinned: true,
                  floating: true,
                  forceElevated: innerBoxIsScrolled,
                  bottom: TabBar(
                    tabs: <Tab>[
                      Tab(text: 'ONE'),
                      Tab(text: 'TWO'),
                    ],
                    controller: _tabController,
                  ),
                ),
              ];
            },
            body: TabBarView(
              controller: _tabController,
              children: <Widget>[
                Center(
                  child: Text(
                    "xyz",
                    style: TextStyle(fontSize: 60),
                  ),
                ),
                Text("xyz"),
              ],
            ),
          ),
        );
      }