Basic example of Animation from Provider

main.dart

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

void main() {
  runApp(ChangeNotifierProvider(
      create: (context) => MyProvider(), child: MyApp()));
}

class AnimationEvent {
  List<int> shapeId;
  bool moved;
  String dialogText;

  AnimationEvent({this.shapeId, this.moved, this.dialogText});
}

class MyProvider extends ChangeNotifier {
  var moved = List<bool>.filled(4, false);
  String dialogText;

  void createEvents() {
    var events = <AnimationEvent>[];

    events.add(AnimationEvent(shapeId: [0], moved: true));
    events.add(AnimationEvent(shapeId: [1], moved: true));
    events.add(AnimationEvent(shapeId: [2], moved: true));
    events.add(AnimationEvent(shapeId: [3], moved: true));

    events.add(AnimationEvent(dialogText: "All 4 cards moved"));

    // This is commented for now - since it would cancel each individual animation
    //events.add(AnimationEvent(shapeId: [0, 1, 2, 3], moved: false));

    for (var event in events) {
      processEvent(event);
    }
  }

  void processEvent(AnimationEvent event) {
    if (event.shapeId != null) {
      for (var shape in event.shapeId) {
        moved[shape] = event.moved;
      }
    }

    if (event.dialogText != null) {
      dialogText = event.dialogText;
    }

    notifyListeners();
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Sequential Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Sequential Demo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  void _move(BuildContext context) {
    var provider = Provider.of<MyProvider>(context, listen: false);
    provider.createEvents();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Consumer<MyProvider>(builder: (context, model, child) {
        if ((model.dialogText ?? "") != "") {
          WidgetsBinding.instance.addPostFrameCallback((_) async {
            await showDialog(
                context: context,
                builder: (BuildContext context) {
                  return SimpleDialog(
                      title: Text(model.dialogText),
                      children: <Widget>[
                        SimpleDialogOption(
                          onPressed: () {
                            Navigator.pop(context, 'ok');
                          },
                          child: const Text('Ok'),
                        )
                      ]);
                });
            model.dialogText = "";
          });
        }
        return Stack(
          children: [
            ...List.generate(
                4,
                (index) => AnimatedPositioned(
                    top: (index * 120 + 50).toDouble(),
                    left: model.moved[index] ? 300 : 50,
                    duration: Duration(seconds: 3),
                    child: Container(
                      child: Text('Card $index'),
                      color: Colors.blue,
                      height: 100,
                      width: 50,
                    )))
          ],
        );
      }),
      floatingActionButton: FloatingActionButton(
        onPressed: () => _move(context),
        tooltip: 'Move',
        child: Icon(Icons.add),
      ),
    );
  }
}