【发布时间】：2021-10-28 03:21:44
【问题描述】：
以下是我使用 StreamBuilder 从 Firestore 获得的名为“week”的示例 QueryDocumentSnapshot。 我正在寻找一种方法来显示这些或多或少复杂的数据，例如 Card-Widget，其中包含来自 Flutter 项目中每个快照的信息。
{
"days":{
"3": {
"activities": {
"1628658343103": {
"query": "I am watering the plants",
"finished": false,
"params": [
{
"pronounsDefinite": "I"
},
{
"verbsHelpPresent": "am"
},
{
"verbsGerund": "watering"
},
{
"articles": "the"
},
{
"nouns": "plant"
}
],
"intent": "gHomesAndBuildingsGardensAC",
"duration": 3
},
"1628673512954": {
"query": "I am cutting the bushes",
"finished": false,
"params": [
{
"pronounsDefinite": "I"
},
{
"verbsHelpPresent": "am"
},
{
"verbsGerund": "cutting"
},
{
"articles": "the"
},
{
"nouns": "bush"
}
],
"intent": "gHomesAndBuildingsGardensAC",
"duration": 3
},
"1628673476549": {
"query": "I work in the garden",
"finished": false,
"params": [
{
"pronounsDefinite": "I"
},
{
"verbsInfinitiv": "work"
},
{
"prepositions": "in"
},
{
"articles": "the"
},
{
"nouns": "garden"
}],
"intent": "gHomesAndBuildingsGardensAC",
"duration": 4
}
}
},
"4": {
"activities": {
"1628658343104": {
"query": "I am watering the plants",
"finished": false,
"params": [
{
"pronounsDefinite": "I"
},
{
"verbsHelpPresent": "am"
},
{
"verbsGerund": "watering"
},
{
"articles": "the"
},
{
"nouns": "plant"
}
],
"intent": "gHomesAndBuildingsGardensAC",
"duration": 3
},
"1628673512956": {
"query": "I am cutting the bushes",
"finished": false,
"params": [
{
"pronounsDefinite": "I"
},
{
"verbsHelpPresent": "am"
},
{
"verbsGerund": "cutting"
},
{
"articles": "the"
},
{
"nouns": "bush"
}
],
"intent": "gHomesAndBuildingsGardensAC",
"duration": 3
},
"1628673476559": {
"query": "I work in the garden",
"finished": false,
"params": [
{
"pronounsDefinite": "I"
},
{
"verbsInfinitiv": "work"
},
{
"prepositions": "in"
},
{
"articles": "the"
},
{
"nouns": "garden"
}],
"intent": "gHomesAndBuildingsGardensAC",
"duration": 3
}
}
}
}
}
问题来了： 我有一个 ListView.builder 方法，它为每个快照文档构建一个小部件，就像上面的那样。
“活动”中的数字键是时间戳。 我可以使用这个来显示一些文本：
...
Text(
week['days']['3']['activities']['1628658343103']['query'].toString()
), //Which displays: "I am watering the plants"
但是这样我就必须知道每个时间戳，然后用确切的数字来调用它，这显然是行不通的。
如何使用“forEach()”之类的东西来遍历活动中的所有现有条目？
我还使用https://app.quicktype.io为此构建了一个模型类 但随后它会引发 FormatException，因为我在尝试此操作时尝试将 QueryDocumentSnapshot 粘贴到类中：
Widget buildCard(BuildContext context, DocumentSnapshot week) {
final dataFromWeek = dataFromWeekFromJson(week.toString());
return new Container(.....);
//In this Container, all the text from json should be displayed
}
这是我从 JSON QuickType 工具获得的模型类。
// To parse this JSON data, do
//
// final dataFromWeek = dataFromWeekFromJson(jsonString);
import 'dart:convert';
DataFromWeek dataFromWeekFromJson(String str) =>
DataFromWeek.fromJson(json.decode(str));
String dataFromWeekToJson(DataFromWeek data) => json.encode(data.toJson());
class DataFromWeek {
DataFromWeek({
this.days,
});
Map<String, Day> days;
factory DataFromWeek.fromJson(Map<String, dynamic> json) => DataFromWeek(
days: Map.from(json["days"])
.map((k, v) => MapEntry<String, Day>(k, Day.fromJson(v))),
);
Map<String, dynamic> toJson() => {
"days": Map.from(days)
.map((k, v) => MapEntry<String, dynamic>(k, v.toJson())),
};
}
class Day {
Day({
this.activities,
});
Map<String, Activity> activities;
factory Day.fromJson(Map<String, dynamic> json) => Day(
activities: Map.from(json["activities"])
.map((k, v) => MapEntry<String, Activity>(k, Activity.fromJson(v))),
);
Map<String, dynamic> toJson() => {
"activities": Map.from(activities)
.map((k, v) => MapEntry<String, dynamic>(k, v.toJson())),
};
}
class Activity {
Activity({
this.query,
this.finished,
this.params,
this.intent,
this.duration,
});
String query;
bool finished;
List<Param> params;
String intent;
int duration;
factory Activity.fromJson(Map<String, dynamic> json) => Activity(
query: json["query"],
finished: json["finished"],
params: List<Param>.from(json["params"].map((x) => Param.fromJson(x))),
intent: json["intent"],
duration: json["duration"],
);
Map<String, dynamic> toJson() => {
"query": query,
"finished": finished,
"params": List<dynamic>.from(params.map((x) => x.toJson())),
"intent": intent,
"duration": duration,
};
}
class Param {
Param({
this.pronounsDefinite,
this.verbsHelpPresent,
this.verbsGerund,
this.articles,
this.nouns,
this.verbsInfinitiv,
this.prepositions,
});
String pronounsDefinite;
String verbsHelpPresent;
String verbsGerund;
String articles;
String nouns;
String verbsInfinitiv;
String prepositions;
factory Param.fromJson(Map<String, dynamic> json) => Param(
pronounsDefinite:
json["pronounsDefinite"] == null ? null : json["pronounsDefinite"],
verbsHelpPresent:
json["verbsHelpPresent"] == null ? null : json["verbsHelpPresent"],
verbsGerund: json["verbsGerund"] == null ? null : json["verbsGerund"],
articles: json["articles"] == null ? null : json["articles"],
nouns: json["nouns"] == null ? null : json["nouns"],
verbsInfinitiv:
json["verbsInfinitiv"] == null ? null : json["verbsInfinitiv"],
prepositions:
json["prepositions"] == null ? null : json["prepositions"],
);
Map<String, dynamic> toJson() => {
"pronounsDefinite": pronounsDefinite == null ? null : pronounsDefinite,
"verbsHelpPresent": verbsHelpPresent == null ? null : verbsHelpPresent,
"verbsGerund": verbsGerund == null ? null : verbsGerund,
"articles": articles == null ? null : articles,
"nouns": nouns == null ? null : nouns,
"verbsInfinitiv": verbsInfinitiv == null ? null : verbsInfinitiv,
"prepositions": prepositions == null ? null : prepositions,
};
}
我实际上并不想显示“参数”，但如果有一些灵活性会很棒，这就是为什么我尝试使用模型类在“卡片小部件”中显示快照数据的原因。
【问题讨论】：
标签： json firebase flutter dart