android - 无法将类型“ X”的值分配给类型“列表”的变量

我正在学习颤动，并想像本文中一样解析JSON ，但收到此错误。

lib / service / apiservice.dart：11：33：错误：无法将类型为“数据”的值分配给类型为“列表”的变量。-“数据”来自“ package：gocorona / models / totals.dart”（“ lib / models / totals.dart”）。-“列表”来自“ dart：core”。最终列表数据= dataFromJson（response.body）;

lib / service / apiservice.dart

import 'package:http/http.dart' as http;
import 'package:gocorona/models/totals.dart';

class ApiServices {

  static const String url = 'https://api.rootnet.in/covid19-in/stats/latest';
static Future<List<Data>> getDataFromAPI() async {
    try {
      final response = await http.get(url);
      if (200 == response.statusCode) {
        final List<Data> data = dataFromJson(response.body);
        return data;
      } else {
        return List<Data>();
      }
    } catch (e) {
      return List<Data>();
    }
  }
}

lib / models / totals.dart

import 'dart:convert';

Data dataFromJson(String str) => Data.fromJson(json.decode(str));

String dataToJson(Data data) => json.encode(data.toJson());

class Data {
    bool success;
    DataClass data;
    DateTime lastRefreshed;
    DateTime lastOriginUpdate;

    Data({
        this.success,
        this.data,
        this.lastRefreshed,
        this.lastOriginUpdate,
    });

    factory Data.fromJson(Map<String, dynamic> json) => Data(
        success: json["success"],
        data: DataClass.fromJson(json["data"]),
        lastRefreshed: DateTime.parse(json["lastRefreshed"]),
        lastOriginUpdate: DateTime.parse(json["lastOriginUpdate"]),
    );

    Map<String, dynamic> toJson() => {
        "success": success,
        "data": data.toJson(),
        "lastRefreshed": lastRefreshed.toIso8601String(),
        "lastOriginUpdate": lastOriginUpdate.toIso8601String(),
    };
}

class DataClass {
    Summary summary;
    List<UnofficialSummary> unofficialSummary;
    List<Regional> regional;

    DataClass({
        this.summary,
        this.unofficialSummary,
        this.regional,
    });

    factory DataClass.fromJson(Map<String, dynamic> json) => DataClass(
        summary: Summary.fromJson(json["summary"]),
        unofficialSummary: List<UnofficialSummary>.from(json["unofficial-summary"].map((x) => UnofficialSummary.fromJson(x))),
        regional: List<Regional>.from(json["regional"].map((x) => Regional.fromJson(x))),
    );

    Map<String, dynamic> toJson() => {
        "summary": summary.toJson(),
        "unofficial-summary": List<dynamic>.from(unofficialSummary.map((x) => x.toJson())),
        "regional": List<dynamic>.from(regional.map((x) => x.toJson())),
    };
}

class Regional {
    String loc;
    int confirmedCasesIndian;
    int discharged;
    int deaths;
    int confirmedCasesForeign;
    int totalConfirmed;

    Regional({
        this.loc,
        this.confirmedCasesIndian,
        this.discharged,
        this.deaths,
        this.confirmedCasesForeign,
        this.totalConfirmed,
    });

    factory Regional.fromJson(Map<String, dynamic> json) => Regional(
        loc: json["loc"],
        confirmedCasesIndian: json["confirmedCasesIndian"],
        discharged: json["discharged"],
        deaths: json["deaths"],
        confirmedCasesForeign: json["confirmedCasesForeign"],
        totalConfirmed: json["totalConfirmed"],
    );

    Map<String, dynamic> toJson() => {
        "loc": loc,
        "confirmedCasesIndian": confirmedCasesIndian,
        "discharged": discharged,
        "deaths": deaths,
        "confirmedCasesForeign": confirmedCasesForeign,
        "totalConfirmed": totalConfirmed,
    };
}

class Summary {
    int total;
    int confirmedCasesIndian;
    int confirmedCasesForeign;
    int discharged;
    int deaths;
    int confirmedButLocationUnidentified;

    Summary({
        this.total,
        this.confirmedCasesIndian,
        this.confirmedCasesForeign,
        this.discharged,
        this.deaths,
        this.confirmedButLocationUnidentified,
    });

    factory Summary.fromJson(Map<String, dynamic> json) => Summary(
        total: json["total"],
        confirmedCasesIndian: json["confirmedCasesIndian"],
        confirmedCasesForeign: json["confirmedCasesForeign"],
        discharged: json["discharged"],
        deaths: json["deaths"],
        confirmedButLocationUnidentified: json["confirmedButLocationUnidentified"],
    );

    Map<String, dynamic> toJson() => {
        "total": total,
        "confirmedCasesIndian": confirmedCasesIndian,
        "confirmedCasesForeign": confirmedCasesForeign,
        "discharged": discharged,
        "deaths": deaths,
        "confirmedButLocationUnidentified": confirmedButLocationUnidentified,
    };
}

class UnofficialSummary {
    String source;
    int total;
    int recovered;
    int deaths;
    int active;

    UnofficialSummary({
        this.source,
        this.total,
        this.recovered,
        this.deaths,
        this.active,
    });

    factory UnofficialSummary.fromJson(Map<String, dynamic> json) => UnofficialSummary(
        source: json["source"],
        total: json["total"],
        recovered: json["recovered"],
        deaths: json["deaths"],
        active: json["active"],
    );

    Map<String, dynamic> toJson() => {
        "source": source,
        "total": total,
        "recovered": recovered,
        "deaths": deaths,
        "active": active,
    };
}

lib / screens / states.dart

import 'package:flutter/material.dart';
import 'package:gocorona/models/totals.dart';
import 'package:gocorona/service/apiservice.dart';

class Statewise extends StatefulWidget {
  @override
  _StatewiseState createState() => _StatewiseState();
}

class _StatewiseState extends State<Statewise> {
  List<Data> _datafromApi;
  bool _isloading;

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

    _isloading = true;
    ApiServices.getDataFromAPI().then((data) {
      setState(() {
        _datafromApi = data;
        _isloading = false;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    if (_isloading) {
      return Container(
        child: Center(
          child: CircularProgressIndicator(),
        ),
      );
    } else {
      return Scaffold(
        body: ListView.builder(
            itemCount: _datafromApi == null ? 0 : _datafromApi.length,
            itemBuilder: (context, index) {
              Data datas = _datafromApi[index];
              print(datas?.toString() ?? "Empty");
              return ListTile(
                  title: Text(
                datas.data.regional[0].loc.toString(),
                style: TextStyle(color: Colors.black),
              ));
            }),
      );
    }
  }
}

编译器消息：

lib/service/apiservice.dart:11:33: Error: A value of type 'Data' can't be assigned to a variable of type 'List<Data>'.
 - 'Data' is from 'package:gocorona/models/totals.dart' ('lib/models/totals.dart').
 - 'List' is from 'dart:core'.
        final List<Data> data = dataFromJson(response.body);
                                ^

Flutter 医生

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, v1.17.0, on Microsoft Windows [Version 10.0.18362.778], locale en-IN)

[√] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[√] Android Studio (version 3.6)
[√] VS Code (version 1.45.0)
[√] Connected device (1 available)

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