问重新打开对话框时，Flutter gif不会再次播放

EN

import 'package:flutter/material.dart';
import 'package:geocash_flutter/services/size_config.dart';

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

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

class _LoseDialogState extends State<LoseDialog>{

  @override
  Widget build(BuildContext context) {
    SizeConfig().init(context);

    return WillPopScope(
      onWillPop: () async => false,
      child: AlertDialog(
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Image.asset(
              'assets/lose.gif',
              height: 35.0 * SizeConfig.blockSizeVertical,
            ),
          ],
        ),
      ),
    );
  }
}