MySliverPersistentHeader example

main.dart

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

void main() {
  runApp(const MyApp());
}

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  final String title;

  const MyHomePage({super.key, required this.title});

  @override
  State<StatefulWidget> createState() => MyHomePageState();
}

class MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.grey.shade50,
        child: Column(
          children: [
            buildAppBar(context),
            Expanded(
              child: DefaultTabController(
                length: 2,
                child: CustomScrollView(
                  slivers: [
                    buildHeader(context),
                    buildList(context),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  buildAppBar(BuildContext context) {
    return Container(
      height: 100,
      color: const Color.fromARGB(255, 0, 49, 90),
    );
  }

  buildAvatar(BuildContext context) {
    return Container(
      width: 180,
      height: 180,
      margin: const EdgeInsets.symmetric(vertical: 16),
      color: Colors.blueGrey,
      child: const Center(
        child: Text("Avatar"),
      ),
    );
  }

  buildDisplayName(BuildContext context) {
    return Center(
      child: Container(
        width: 120,
        height: 30,
        color: Colors.blueGrey,
      ),
    );
  }

  buildTabBar(BuildContext context) {
    return Container(
      height: 60,
      color: Colors.grey,
      margin: const EdgeInsets.only(top: 8, left: 24, right: 24, bottom: 0),
    );
  }

  buildHeader(BuildContext context) {
    return SliverPersistentHeader(
      pinned: true,
      delegate: MySliverPersistentHeaderDelegate(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.end,
          children: [
            buildAvatar(context),
            buildDisplayName(context),
            buildTabBar(context),
          ],
        ),
        // child: buildAvatar(context),
      ),
    );
  }

  buildList(BuildContext context) {
    return SliverList(
      delegate: SliverChildBuilderDelegate(
        (context, index) {
          return Container(
            padding: const EdgeInsets.all(8),
            alignment: Alignment.centerLeft,
            height: 40,
            child: Text('$index'),
          );
        },
        childCount: 100,
      ),
    );
  }
}

class MySliverPersistentHeaderDelegate extends SliverPersistentHeaderDelegate {
  final Widget child;

  MySliverPersistentHeaderDelegate({required this.child});

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    print(shrinkOffset);
    // print(maxExtent - shrinkOffset);
    return Stack(
      children: [
        Positioned.fill(
          top: 0 - shrinkOffset,
          child: Container(
            color: Colors.orange,
            child: Align(
              alignment: Alignment.bottomCenter,
              child: child,
            ),
          ),
        )
      ],
    );
  }

  @override
  double get maxExtent => 310;

  @override
  double get minExtent => 60;

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