how to map response to Map<String, Object> in flutter

Question

Here is my object

class CustomerDomain {
  String customerID;
  String citizenID;
  String status;
  String title;
  String name;
  String email;
  String phoneNumber;
  Map<String, ServiceDetail> serviceDetails;
  int remainingMinute;
  Map<String, ReferenceChannel> referenceChannels;
  String omiseCustomerID;

  CustomerDomain({
    this.customerID,
    this.citizenID,
    this.status,
    this.title,
    this.name,
    this.email,
    this.phoneNumber,
    this.serviceDetails,
    this.remainingMinute,
    this.referenceChannels,
    this.omiseCustomerID,
  });

  factory CustomerDomain.fromJson(Map<String, dynamic> parsedJson) {
    return CustomerDomain(
      customerID: parsedJson['customerID'],
      citizenID: parsedJson['citizenID'],
      status: parsedJson['status'],
      title: parsedJson['title'],
      name: parsedJson['name'],
      email: parsedJson['email'],
      phoneNumber: parsedJson['phoneNumber'],
      serviceDetails: parsedJson['serviceDetailsails'],
      remainingMinute: parsedJson['remainingMinute'],
      referenceChannels: parsedJson['referenceChannels'],
      omiseCustomerID: parsedJson['omiseCustomerID'],
    );
  }
}

After calling a service, I return my response like this

if (response.statusCode == 200) {
      print('entranceService3');
      return CustomerDomain.fromJson(json.decode(response.body));
    }

I printing the value like customerID and it works. But I cannot use print the value in the ReferenceChannel from referenceChannels. When I convert referenceChannels into list and then string, and print it. I got something like this

[{channel:channel1,code:code1,secondCode:code2}]

So, I think that I didn't map the json correctly because the value that has type Map<String, Object> didn't work properly when I try to the value of the object.

Answer 1

Map is also a Key Value like JSON so it would look something

{
"referenceChannels": {
"key":"value"
}

} if your value is another object then

"key":{"key1":"value","key1":"value"  }

Overall something like this:

{
"referenceChannels": {
"key":{"key1":"value","key2":"value"  }
}

You will have to iterate through the Reference Channel Object JSON like you did for CustomerDomain. You can also create a FromJson() method in Reference Channel class and use that in the fromJson of Customer Domain like this:

 factory CustomerDomain.fromJson(Map<String, dynamic> parsedJson) {
    return CustomerDomain(
// Add other fields here 
      referenceChannels: parsedJson['referenceChannels'].fromJson,
  
    );
  }

Also try creating the class here https://app.quicktype.io/. This website will create your class with toJson() and FromJson() methods

Answer 2

make sure, that your JSON string is a proper JSON string, in your case, the string should be as following:

'[{"channel":"channel1","code":"code1","secondCode":"code2"}]'

check out the snippet, I used the JSON.parse function and it works.

let jsonString = '[{"channel":"channel1","code":"code1","secondCode":"code2"}]';
let jsonArray = JSON.parse(jsonString);

console.log('channel name: 'jsonArray[0].channel);
console.log(jsonArray);

Answer 3

As you have already known that you cannot do something like this:

customDomain: parsedJson

but instead you need a CustomDomain.fromJson to map the value and ensure the type-safety.

So the same concept applies to ServiceDetailsails and ReferenceChannels as well. You will need to parse the whole object like:

factory CustomerDomain.fromJson(Map<String, dynamic> parsedJson) {
return CustomerDomain(
  customerID: parsedJson['customerID'],
  citizenID: parsedJson['citizenID'],
  status: parsedJson['status'],
  title: parsedJson['title'],
  name: parsedJson['name'],
  email: parsedJson['email'],
  phoneNumber: parsedJson['phoneNumber'],
  serviceDetails: ServiceDetailsails.fromJson(parsedJson['serviceDetailsails']),
  remainingMinute: parsedJson['remainingMinute'],
  referenceChannels: ReferenceChannels.fromJson(parsedJson['referenceChannels']),
  omiseCustomerID: parsedJson['omiseCustomerID'],
);}

If you are using dart, you can also check this doc for more details: https://flutter.dev/docs/development/data-and-backend/json