问无法将animation.json文件加载到flutter项目

EN

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: ListView(
          children: [
            // Load a Lottie file from your assets
            Lottie.asset('assets/optimal.json'),

            // Load a Lottie file from a remote url
            Lottie.network(
                'https://raw.githubusercontent.com/xvrh/lottie-flutter/master/example/assets/Mobilo/A.json'),

            // Load an animation and its images from a zip file
            // Lottie.asset('assets/lottiefiles/angel.zip'),
          ],
        ),
      ),
    );
  }
}

> FAILURE: Build failed with an exception.
> 
> * Where: Script 'C:\src\flutter\packages\flutter_tools\gradle\flutter.gradle' line:
> 904
> 
> * What went wrong: Execution failed for task ':app:compileFlutterBuildDebug'.
> > Process 'command 'C:\src\flutter\bin\flutter.bat'' finished with non-zero exit value 1
> 
> * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
> 
> * Get more help at https://help.gradle.org
> 
> BUILD FAILED in 44s Exception: Gradle task assembleDebug failed with
> exit code 1