【发布时间】：2022-01-11 11:51:15
【问题描述】：
我正在尝试根据从 JSON API 获得的数据按日期对列表进行排序。 JSON 是一个被序列化为模型的 Map。我尝试了几件事，但都没有奏效。知道该怎么做吗？不确定是否应该在 Listview.builder 或 API 请求类中对其进行排序。
API 请求类
import 'package:http/http.dart' as http;
import 'package:lets_chat/app/modules/events/models/events.dart';
class EventApi {
static var client = http.Client();
static Future<Event?> fetchEvents() async {
final response = await client.get(Uri.parse(
'https://xposure.ae/wp-json/wp/auditorium/v1/events'));
if (response.statusCode == 200) {
var jsonString = response.body;
return eventFromJson(jsonString);
} else {
//show error message
return null;
}
}
}
模型类
import 'package:meta/meta.dart';
import 'dart:convert';
Event eventFromJson(String str) => Event.fromJson(json.decode(str));
String eventToJson(Event data) => json.encode(data.toJson());
class Event {
Event({
@required this.data,
});
List<Datum>? data;
@override
void initState() {
data!.sort((a, b) => a.datetime.compareTo(b.datetime));
}
factory Event.fromJson(Map<String, dynamic> json) => Event(
data: json["data"] == null ? null : List<Datum>.from(json["data"].map((x) => Datum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"data": data == null ? null : List<dynamic>.from(data!.map((x) => x.toJson())),
};
}
class Datum {
Datum({
required this.eventtitle,
required this.description,
required this.eventImage,
required this.speaker,
required this.datetime,
required this.location,
});
String eventtitle;
String description;
String eventImage;
Speaker? speaker;
String datetime;
Location? location;
factory Datum.fromJson(Map<String, dynamic> json) => Datum(
eventtitle: json["Eventtitle"] == null ? null : json["Eventtitle"],
description: json["Description"] == null ? null : json["Description"],
eventImage: json["event_image"] == null ? null : json["event_image"],
speaker: json["Speaker"] == null ? null : Speaker.fromJson(json["Speaker"]),
datetime: json["datetime"] == null ? null : json["datetime"],
location: json["Location"] == null ? null : Location.fromJson(json["Location"]),
);
Map<String, dynamic> toJson() => {
"Eventtitle": eventtitle == null ? null : eventtitle,
"Description": description == null ? null : description,
"event_image": eventImage == null ? null : eventImage,
"Speaker": speaker == null ? null : speaker!.toJson(),
"datetime": datetime == null ? null : datetime,
"Location": location == null ? null : location!.toJson(),
};
}
class Location {
Location({
required this.venue,
required this.address,
});
Venue? venue;
Address? address;
factory Location.fromJson(Map<String, dynamic> json) => Location(
venue: json["venue"] == null ? null : venueValues.map[json["venue"]],
address: json["address"] == null ? null : addressValues.map[json["address"]],
);
Map<String, dynamic> toJson() => {
"venue": venue == null ? null : venueValues.reverse[venue],
"address": address == null ? null : addressValues.reverse[address],
};
}
enum Address { SHARJAH_BR_SHARJAH_BR_61110_BR_UNITED_ARAB_EMIRATES }
final addressValues = EnumValues({
"Sharjah</br>Sharjah,</br>61110,</br>United Arab Emirates": Address.SHARJAH_BR_SHARJAH_BR_61110_BR_UNITED_ARAB_EMIRATES
});
enum Venue { XPOSURE_INTERNATIONAL_PHOTOGRAPHY_FESTIVAL }
final venueValues = EnumValues({
"Xposure International Photography Festival": Venue.XPOSURE_INTERNATIONAL_PHOTOGRAPHY_FESTIVAL
});
class Speaker {
Speaker({
required this.speakername,
required this.link,
});
String speakername;
String link;
factory Speaker.fromJson(Map<String, dynamic> json) => Speaker(
speakername: json["speakername"] == null ? null : json["speakername"],
link: json["link"] == null ? null : json["link"],
);
Map<String, dynamic> toJson() => {
"speakername": speakername == null ? null : speakername,
"link": link == null ? null : link,
};
}
class EnumValues<T> {
Map<String, T> map;
late Map<T, String> reverseMap;
EnumValues(this.map);
Map<T, String> get reverse {
if (reverseMap == null) {
reverseMap = map.map((k, v) => new MapEntry(v, k));
}
return reverseMap;
}
}
偶数视图类
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:get/instance_manager.dart';
import 'package:lets_chat/app/modules/events/views/event_details.dart';
import 'package:lets_chat/app/modules/events/controllers/events_controller.dart';
import 'package:lets_chat/app/modules/events/views/event_tile.dart';
class EventView extends StatelessWidget {
final EventsController eventController = Get.put(EventsController());
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.grey[800],
appBar: AppBar(
backgroundColor: Colors.grey[850],
elevation: 2,
leading: GestureDetector(
onTap: () {
Navigator.pop(context);
},
child: const Icon(
Icons.arrow_back_ios,
color: Colors.grey,
),
),
),
body: Column(
children: [
Expanded(
child: Obx(() {
if (eventController.isLoading.value)
return Center(child: CircularProgressIndicator(
color: Colors.red,
));
else {
return ListView.builder(
itemCount: eventController.event.value!.data!.length,
itemBuilder: (context, index) {
return GestureDetector(
onTap: () {
Navigator.push(
context, MaterialPageRoute(builder: (context) => EventDetails(event: eventController.event.value!.data![index]))
);
},
child: EventTile(eventController.event.value!.data![index]));
});
}
}),
)
],
),
);
}
}
【问题讨论】：