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Flutter UI #83: Fun with Staggered Animations in Flutter

Tutorial and code of Staggered Animations in Flutter. Copy and paste the below code as per your requirements.

flutter_staggered_animations: ^1.0.0

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

void main() => runApp(App());

class App extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        brightness: Brightness.light,
        scaffoldBackgroundColor: const Color.fromRGBO(239, 238, 239, 1.0),
      ),
      home: const CardGridScreen(),
    );
  }
}
class CardGridScreen extends StatefulWidget {
  const CardGridScreen({Key? key}) : super(key: key);

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

class _CardGridScreenState extends State<CardGridScreen> {
  @override
  Widget build(BuildContext context) {
    var columnCount = 3;

    return AutoRefresh(
      duration: const Duration(milliseconds: 2000),
      child: Scaffold(
        appBar: AppBar(title: const Center(child: Text("Staggered Animations"),),),
        body: SafeArea(
          child: AnimationLimiter(
            child: GridView.count(
              childAspectRatio: 1.0,
              padding: const EdgeInsets.all(8.0),
              crossAxisCount: columnCount,
              children: List.generate(
                100,
                    (int index) {
                  return AnimationConfiguration.staggeredGrid(
                    columnCount: columnCount,
                    position: index,
                    duration: const Duration(milliseconds: 375),
                    child: const ScaleAnimation(
                      scale: 0.5,
                      child: FadeInAnimation(
                        child: EmptyCard(),
                      ),
                    ),
                  );
                },
              ),
            ),
          ),
        ),
      ),
    );
  }
}
class AutoRefresh extends StatefulWidget {
  final Duration duration;
  final Widget child;

  const AutoRefresh({
    Key? key,
    required this.duration,
    required this.child,
  }) : super(key: key);

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

class _AutoRefreshState extends State<AutoRefresh> {
  int? keyValue;
  ValueKey? key;

  Timer? _timer;

  @override
  void initState() {
    super.initState();

    keyValue = 0;
    key = ValueKey(keyValue);

    _recursiveBuild();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      key: key,
      child: widget.child,
    );
  }

  void _recursiveBuild() {
    _timer = Timer(
      widget.duration,
          () {
        setState(() {
          keyValue = keyValue! + 1;
          key = ValueKey(keyValue);
          _recursiveBuild();
        });
      },
    );
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }
}
class EmptyCard extends StatelessWidget {
  final double? width;
  final double? height;

  const EmptyCard({
    Key? key,
    this.width,
    this.height,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: width,
      height: height,
      margin: const EdgeInsets.symmetric(vertical: 8.0, horizontal: 8.0),
      decoration: const BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.all(Radius.circular(4.0)),
        boxShadow: <BoxShadow>[
          BoxShadow(
            color: Colors.black12,
            blurRadius: 4.0,
            offset: Offset(0.0, 4.0),
          ),
        ],
      ),
    );
  }
}

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