Swift3 Json Parsing - 如何访问相关字段

Question

在从 JSON 访问 Swift 3 中所需的信息时遇到了真正的困难，这就是我所拥有的：

override func viewDidLoad()
{
    super.viewDidLoad()

    let url = URL(string: "http://api.brewerydb.com/v2/beers?key=e3bdce7d0a80584c784cdc4b02459add&name=budweiser")

    URLSession.shared.dataTask(with:url!) { (data, response, error) in
        if error != nil {
            print(error!)

        }
        else {

            do {

                let parsedData = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
               // print(parsedData)


                 let dataLevel = parsedData["data"] as? NSDictionary


                print(dataLevel)

                let abv = dataLevel?["abv"] as? AnyObject
                print(abv!)




            } catch let error as NSError {
                print(error)
            }
        }

        }.resume()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}

JSON 文件的链接在代码中 - 为什么我的代码没有返回“数据”部分，我如何检索啤酒的“名称”、“abv”和“描述”？

Answer 1

当您处理 JSON 时，我认为使用以下工具会很有帮助： jsonformatter.curiousconcept.com 或者 jsonlint.com 这有助于我理解结构和我正在处理的数据类型。

如果您查看您的 json，您会注意到，正如 Eric Aya 所说，数据是一个数组而不是字典：

{
    "currentPage": 1,
    "numberOfPages": 1,
    "totalResults": 1,
    "data": [{
        "id": "1P45iR",
        "name": "Budweiser",
        "nameDisplay": "Budweiser",
        "description": "Known as \u201cThe King of Beers\u201d, Budweiser was first introduced by Adolphus Busch in 1876 and is brewed with the same high quality standards today. Budweiser is a medium-bodied, flavorful, crisp American-style lager, craft brewed with a blend of premium hop varieties, and associated with the core American values of celebration and optimism.",
        "abv": "5",
        "glasswareId": 5,
        "srmId": 5,
        "availableId": 1,
        "styleId": 93,
        "isOrganic": "N",
        "labels": {
            "icon": "https:\/\/s3.amazonaws.com\/brewerydbapi\/beer\/1P45iR\/upload_Y13vwL-icon.png",
            "medium": "https:\/\/s3.amazonaws.com\/brewerydbapi\/beer\/1P45iR\/upload_Y13vwL-medium.png",
            "large": "https:\/\/s3.amazonaws.com\/brewerydbapi\/beer\/1P45iR\/upload_Y13vwL-large.png"
        },
        "status": "verified",
        "statusDisplay": "Verified",
        "servingTemperature": "cold",
        "servingTemperatureDisplay": "Cold - (4-7C\/39-45F)",
        "createDate": "2012-01-03 02:42:55",
        "updateDate": "2016-03-21 19:54:11",
        "glass": {
            "id": 5,
            "name": "Pint",
            "createDate": "2012-01-03 02:41:33"
        },
        "srm": {
            "id": 5,
            "name": "5",
            "hex": "FBB123"
        },
        "available": {
            "id": 1,
            "name": "Year Round",
            "description": "Available year round as a staple beer."
        },
        "style": {
            "id": 93,
            "categoryId": 8,
            "category": {
                "id": 8,
                "name": "North American Lager",
                "createDate": "2012-03-21 20:06:46"
            },
            "name": "American-Style Lager",
            "shortName": "American Lager",
            "description": "Light in body and very light to straw in color, American lagers are very clean and crisp and aggressively carbonated. Flavor components should b e subtle and complex, with no one ingredient dominating the others. Malt sweetness is light to mild. Corn, rice, or other grain or sugar adjuncts are often used. Hop bitterness, flavor and aroma are negligible to very light. Light fruity esters are acceptable. Chill haze and diacetyl should be absent.",
            "ibuMin": "5",
            "ibuMax": "13",
            "abvMin": "3.8",
            "abvMax": "5",
            "srmMin": "2",
            "srmMax": "4",
            "ogMin": "1.04",
            "fgMin": "1.006",
            "fgMax": "1.01",
            "createDate": "2012-03-21 20:06:46",
            "updateDate": "2015-04-07 15:39:26"
        }
    }],
    "status": "success"
}

以下代码有效，但我确信有更好的方法可以用更少的代码获得abv：

 override func viewDidLoad()
    {
        super.viewDidLoad()

        let url = URL(string: "http://api.brewerydb.com/v2/beers?key=e3bdce7d0a80584c784cdc4b02459add&name=budweiser")

        URLSession.shared.dataTask(with:url!) { (data, response, error) in
            if error != nil {
                print(error!)

            }
            else {

                do {

                    let parsedData = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as? [String: Any]


                        let jsonArrayData = parsedData?["data"] as! NSArray
                        let data = jsonArrayData[0] as! NSDictionary
                        let abv = data["abv"]
                        print(abv)//Optional(5) in your case


                } catch let error as NSError {
                    print(error)
                }
            }

            }.resume()
    }