JSON中字典的可解码-Swift

Question

I am trying to use Decodable for Dictionaries in JSON data, but I get these errors: 1) Type 'Customer' does not conform to protocol 'Decodable' and 2) Use of undeclared type 'Address'. Any help would be great.

struct Customer : Decodable {
    var firstName : String
    var lastName : String
    var address : Address
}

struct CustomersResponse : Decodable {
    var customers : [Customer]
}

let json = """

{
    "customers":[
        {
            "firstName" : "Henry",
            "lastName" : "Collins",
            "address" : {
                "street" : "1200 Highland Ave",
                "city" : "Houston",
                "state" : "TX",
                "geo" : {
                    "latitude" : 29.76,
                    "longitude" : -95.36
                }
            }
        }

    ]

}

""".data(using: .utf8)!

let customersResponse = try! 
JSONDecoder().decode(CustomersResponse.self, from: json)
print(customersResponse)

Answer 1

The address and geo Dictionaries are considered Nested Objects . You are getting the Type 'Customer' does not conform to protocol 'Decodable' Error because of the Use of undeclared type 'Address' Error. So first, you need to eliminate that second error by declaring the Address type. But, then you will get two new errors if you don't declare Geo , as well. Add the following code to the top of your project to eliminate any errors and produce the proper output.

struct Geo : Decodable {
    var latitude : Double
    var longitude : Double
}


struct Address : Decodable {
    var street : String
    var city : String
    var state : String
    var geo : Geo
}