[英]How to convert NSData to Data in Swift 3?
我正在嘗試創建一個簡單的天氣應用程序,它可以使用 Google Maps api 獲取用戶的位置並顯示簡單的天氣數據。 一切正常,除了我獲取 JSON 並獲取地址的這一部分。
func getAddressForLatLng(latitude: String, longitude: String) {
let url = NSURL(string: "\(baseUrl)latlng=\(latitude),\(longitude)&key=\(apikey)")
let data = NSData(contentsOf: url! as URL)
let json = try! JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.allowFragments) as! Dictionary
if let result = json["results"] as? Dictionary {
if let address = result[0]["address_components"] as? Array {
let number = address[0]["short_name"] as! String
let street = address[1]["short_name"] as! String
let city = address[2]["short_name"] as! String
let state = address[4]["short_name"] as! String
let zip = address[6]["short_name"] as! String
weatherDisplay.text = "\(city),\(state)"
}
}
}
在線上:
let json = try! JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.allowFragments) as! Dictionary
我收到此錯誤:
Cannot invoke 'jsonObject' with an argument list of type '(with: NSData?, options: JSONSerialization.ReadingOptions)'
我究竟做錯了什么?
let nsdata = NSData()
let data = Data(referencing: nsdata)
https://developer.apple.com/documentation/foundation/data/3126627-init
你需要改變一些事情。 首先,您使用的是NSData
。 您應該使用 Swift 類型Data
。 從NSData?
轉換NSData?
Data?
,只是添加as Data?
到變量聲明的末尾。
此外,您的類型是可選的,但您不能傳入可選類型,因此您需要解開它(在本例中,使用if let data = data { /* stuff here */}
):
func getAddressForLatLng(latitude: String, longitude: String) {
let url = NSURL(string: "\(baseUrl)latlng=\(latitude),\(longitude)&key=\(apikey)")
let data = NSData(contentsOf: url! as URL) as Data? // <==== Added 'as Data?'
if let data = data { // <====== Added 'if let'
let json = try! JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.allowFragments) as! Dictionary
if let result = json["results"] as? Dictionary {
if let address = result[0]["address_components"] as? Array {
let number = address[0]["short_name"] as! String
let street = address[1]["short_name"] as! String
let city = address[2]["short_name"] as! String
let state = address[4]["short_name"] as! String
let zip = address[6]["short_name"] as! String
weatherDisplay.text = "\(city),\(state)"
}
}
}
}
更新:
你需要改變的另一件事是:
let json = try! JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.allowFragments) as! Dictionary
當您轉換為Dictionary
類型時,編譯器不知道您在說什么,因為Dictionary
是泛型類型。 所以你需要轉換為Dictionary<String, AnyObject>
或[String: AnyObject]
(它們是一樣的)。
只需投射: let newData = nsData as Data
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