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Null check operator used on a null value（14个回答）
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我开始学习Rest API。我在做一个翻新的酒店应用。我用数据创建模型，当我添加ListView.builder时，它返回错误。
用于空值的空校验运算符
我不确定是因为数据模型有错误还是其他原因。

import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:hotelapp/models/hotel_screen.dart';
import 'package:hotelapp/service/api_service.dart';

import '../../consts/color_palette.dart';

class HotelPage extends StatelessWidget {
  const HotelPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.grey[200],
      appBar: AppBar(
        centerTitle: true,
        title: const Text(
          'Отель',
          style: TextStyle(color: Colors.black),
        ),
        toolbarHeight: 50,
        backgroundColor: backgroundtheme,
        elevation: 0,
      ),
      body: _body()
    );
  }
  FutureBuilder _body() {
    final apiService = ApiService(Dio(BaseOptions(contentType: "application/json")));
    return FutureBuilder(future: apiService.getHotels(), builder: (context, snapshots) {
      if (snapshots.connectionState == ConnectionState.done) {
        final List<HotelModel> hotels = snapshots.data!;
        return _hotels(hotels);
      }
      else {
        return const Center(
          child: CircularProgressIndicator(),
        );
      }
    });
  }

// This where error happens

  Widget _hotels(List<HotelModel> hotels) {
    return ListView.builder(
      itemCount: hotels.length,
        itemBuilder: (context, index) {
      return const Stack(children: [
        Column(
          children: [
            HotelScreen(),
            HotelDescription(),
          ],
        ),
        BottomButtonWidget()
      ]);
    });
  }
}