Parsing Nested JSON Object Flutter - json

Question

I'm trying to parse an object in JSON and I am able to do so successfully without the nested JSON object Opening Hours. I don't know why. Here is the json data:
{
"location": [
{
"id": 4,
"location_name": "PastryMan",
"cbd_products": "",
"phone": "1231231234",
"street_address": "535 7th Ave",
"location_logo": "https://.s3.amazonaws.com/location_logo/water.png",
"location_photo": "https://dispensaries.s3.amazonaws.com/location_photo/delta9.jpg",
"sponsored_location": "Yes",
"city": "New York",
"state": "New York",
"zip_Code": 10018,
"lat": 40.7538935555556,
"lng": -73.9883851111111,
"latlng": "(40.7770112244898, -74.2110798163265)",
"opening_hours": [
{
"day_of_week": "Tuesday",
"opening_time": "08:00:00",
"closing_time": "22:00:00"
},
{
"day_of_week": "Wednesday",
"opening_time": "08:00:00",
"closing_time": "22:00:00"
},
{
"day_of_week": "Thursday",
"opening_time": "08:00:00",
"closing_time": "22:00:00"
},
{
"day_of_week": "Friday",
"opening_time": "08:00:00",
"closing_time": "22:00:00"
},
{
"day_of_week": "Saturday",
"opening_time": "08:00:00",
"closing_time": "22:00:00"
},
{
"day_of_week": "Sunday",
"opening_time": "08:00:00",
"closing_time": "22:00:00"
},
{
"day_of_week": 7,
"opening_time": "08:00:00",
"closing_time": "22:00:00"
}
],
"ratings": 0.0
},}
I have setup my class like this:
class Location {
int id;
String name;
String phone;
String address;
String city;
String locationPhoto;
String locationLogo;
String state;
num lat;
num long;
List<OpeningHours> openingHours;
String cbdProducts;
num rating;
String zipCode;
String latlng;
String sponsored;
location(
{this.id,
this.name,
this.cbdProducts,
this.phone,
this.address,
this.locationLogo,
this.locationPhoto,
this.sponsored,
this.city,
this.state,
this.zipCode,
this.lat,
this.long,
this.latlng,
this.openingHours,
this.rating});
location.fromJson(Map<String, dynamic> json) {
id = json['id'];
name = json['location_name'];
cbdProducts = json['cbd_products'];
phone = json['phone'];
address = json['street_address'];
locationLogo = json['location_logo'];
locationPhoto = json['location_photo'];
address = json['sponsored_location'];
city = json['city'];
state = json['state'];
zipCode = json['zip_Code'];
lat = json['lat'];
long = json['long'];
latlng = json['latlng'];
if (json['opening_hours'] != null) {
openingHours = new List<OpeningHours>();
json['opening_hours'].forEach((v) {
openingHours.add(new OpeningHours.fromJson(v));
});
}
rating = json['ratings'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['location_name'] = this.name;
data['cbd_products'] = this.cbdProducts;
data['phone'] = this.phone;
data['street_address'] = this.address;
data['location_logo'] = this.locationLogo;
data['location_photo'] = this.locationPhoto;
data['sponsored_location'] = this.address;
data['city'] = this.city;
data['state'] = this.state;
data['zip_Code'] = this.zipCode;
data['lat'] = this.lat;
data['lng'] = this.long;
data['latlng'] = this.latlng;
if (this.openingHours != null) {
data['opening_hours'] = this.openingHours.map((v) => v.toJson()).toList();
}
data['ratings'] = this.rating;
return data;
}
}
class OpeningHours {
String dayOfWeek;
String openingTime;
String closingTime;
OpeningHours({this.dayOfWeek, this.openingTime, this.closingTime});
OpeningHours.fromJson(Map<String, dynamic> json) {
dayOfWeek = json['day_of_week'];
openingTime = json['opening_time'];
closingTime = json['closing_time'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['day_of_week'] = this.dayOfWeek;
data['opening_time'] = this.openingTime;
data['closing_time'] = this.closingTime;
return data;
}
}
Then I call my api in a future to get the details. Here is the api:
Future getLocations() async {
var url = '$_server/api/customer/location/';
HttpClient client = new HttpClient();
HttpClientRequest request = await client.getUrl(Uri.parse(url));
HttpClientResponse response = await request.close();
String reply = await response.transform(utf8.decoder).join();
var responseData = json.decode(reply);
Locations _location = Locations.fromJson(responseData);
currentLocations = _location.location;
print(currentLocations);
return _location.location;
}
When I call the api currentLocations = null. What have I done wrong here?

Answer 1

One of the easiest ways is to use quicktype.io to generate PODO (Plain Old Dart Objects). Just Select the dart language to create PODO and copy-paste your JSON over there and provide the class Name as "Location". I have done that for you now your location class will look like this:
class Location {
Location({
this.location,
});
List<LocationElement> location;
factory Location.fromJson(Map<String, dynamic> json) => Location(
location: List<LocationElement>.from(json["location"].map((x) => LocationElement.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"location": List<dynamic>.from(location.map((x) => x.toJson())),
};
}
class LocationElement {
LocationElement({
this.id,
this.locationName,
this.cbdProducts,
this.phone,
this.streetAddress,
this.locationLogo,
this.locationPhoto,
this.sponsoredLocation,
this.city,
this.state,
this.zipCode,
this.lat,
this.lng,
this.latlng,
this.openingHours,
this.ratings,
});
int id;
String locationName;
String cbdProducts;
String phone;
String streetAddress;
String locationLogo;
String locationPhoto;
String sponsoredLocation;
String city;
String state;
int zipCode;
double lat;
double lng;
String latlng;
List<OpeningHour> openingHours;
int ratings;
factory LocationElement.fromJson(Map<String, dynamic> json) => LocationElement(
id: json["id"],
locationName: json["location_name"],
cbdProducts: json["cbd_products"],
phone: json["phone"],
streetAddress: json["street_address"],
locationLogo: json["location_logo"],
locationPhoto: json["location_photo"],
sponsoredLocation: json["sponsored_location"],
city: json["city"],
state: json["state"],
zipCode: json["zip_Code"],
lat: json["lat"].toDouble(),
lng: json["lng"].toDouble(),
latlng: json["latlng"],
openingHours: List<OpeningHour>.from(json["opening_hours"].map((x) => OpeningHour.fromJson(x))),
ratings: json["ratings"],
);
Map<String, dynamic> toJson() => {
"id": id,
"location_name": locationName,
"cbd_products": cbdProducts,
"phone": phone,
"street_address": streetAddress,
"location_logo": locationLogo,
"location_photo": locationPhoto,
"sponsored_location": sponsoredLocation,
"city": city,
"state": state,
"zip_Code": zipCode,
"lat": lat,
"lng": lng,
"latlng": latlng,
"opening_hours": List<dynamic>.from(openingHours.map((x) => x.toJson())),
"ratings": ratings,
};
}
class OpeningHour {
OpeningHour({
this.dayOfWeek,
this.openingTime,
this.closingTime,
});
dynamic dayOfWeek;
String openingTime;
String closingTime;
factory OpeningHour.fromJson(Map<String, dynamic> json) => OpeningHour(
dayOfWeek: json["day_of_week"],
openingTime: json["opening_time"],
closingTime: json["closing_time"],
);
Map<String, dynamic> toJson() => {
"day_of_week": dayOfWeek,
"opening_time": openingTime,
"closing_time": closingTime,
};
}
This may work now and if still there is issue then you may be getting null value from backend.