lottie-flutter/example/lib/examples/animation_controller.dart

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

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

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

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

class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
  late final AnimationController _controller;

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

    _controller = AnimationController(vsync: this);
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: ListView(
          children: [
            Lottie.asset(
              'assets/LottieLogo1.json',
              controller: _controller,
              onLoaded: (composition) {
                // Configure the AnimationController with the duration of the
                // Lottie file and start the animation.
                _controller
                  ..duration = composition.duration
                  ..forward();
              },
            ),
          ],
        ),
      ),
    );
  }
}