Question

我有这段代码：

 let urls : String = Baseurl+"lat="+latitude+"&lon="+longitude+"&APPID="+apiKey

        if let url = NSURL(string: urls) {
            do {
                let jsonResult = try NSString(contentsOfURL: url, usedEncoding: nil)

                do {
                    if let jsonRes = try NSJSONSerialization.JSONObjectWithData(jsonResult, options: []) as? NSDictionary {
                        print(jsonRes)
                    }
                } catch let error as NSError {
                    print(error.localizedDescription)
                }

但是这行有一个错误：if let jsonRes = try...。错误是：cannot convert value of type 'NSString' to expected argument type 'NSData'。

当我打印jsonResult时，我得到了这个：

{

    "coord":{
        "lon":-0.13,
        "lat":51.51
    },
    "weather":[
        {
            "id":501,
            "main":"Rain",
            "description":"moderate rain",
            "icon":"10d"
        }
    ],
    "base":"stations",
    "main":{
        "temp":284.46,
        "pressure":1023,
        "humidity":76,
        "temp_min":283.15,
        "temp_max":285.15
    },
    "visibility":10000,
    "wind":{
        "speed":7.7,
        "deg":220
    },
    "clouds":{
        "all":75
    },
    "dt":1449755400,
    "sys":{
        "type":1,
        "id":5093,
        "message":0.0414,
        "country":"GB",
        "sunrise":1449734113,
        "sunset":1449762690
    },
    "id":2643743,
    "name":"London",
    "cod":200

}

如何访问这些值？

Answer 1

NSJSONSerialization.JSONObjectWithData()需要NSData个对象，而不是String。

替换

let jsonResult = try NSString(contentsOfURL: url, usedEncoding: nil)

与

let jsonResult = NSData(contentsOfURL: url)

并删除try。

我还应该注意，这不是发出网络请求的最佳方式，您应该使用NSURLSession发出异步请求：

NSURLSession().dataTaskWithURL(NSURL(string: urls)!) { (data, response, error) -> Void in
    if let data = data {
        do {
            let dict = try NSJSONSerialization.JSONObjectWithData(data, options: [])
            print(dict)
        } catch {
            print(error)
        }
    }
}.resume()

NSString到期望参数NSData

1 个答案: