SliverFadeTransition.dart

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

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

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const Center(
          child: MyStatefulWidget(),
        ),
      ),
    );
  }
}

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

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State<MyStatefulWidget>
    with SingleTickerProviderStateMixin {
  late final AnimationController controller = AnimationController(
    duration: const Duration(milliseconds: 1000),
    vsync: this,
  );
  late final Animation<double> animation = CurvedAnimation(
    parent: controller,
    curve: Curves.easeIn,
  );

  @override
  void initState() {
    super.initState();
    animation.addStatusListener((AnimationStatus status) {
      if (status == AnimationStatus.completed) {
        controller.reverse();
      } else if (status == AnimationStatus.dismissed) {
        controller.forward();
      }
    });
    controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return CustomScrollView(slivers: <Widget>[
      SliverFadeTransition(
          opacity: animation,
          sliver: SliverToBoxAdapter(
            child: Center(
              child: Image.network(
                "https://1gew6o3qn6vx9kp3s42ge0y1-wpengine.netdna-ssl.com/wp-content/uploads/prod/2020/10/HERO-ART-microsoft_azure_1920x1000_nologo.jpg",
                width: double.infinity,
                height: 300,
                fit: BoxFit.cover,
              ),
            ),
          ))
    ]);
  }
}