问题描述
我不是一个iOS开发者，必须对Swift / AlamoFire项目（不是我的）进行一些修改，并且有点迷失。
我有以下JSON：
{metro_locations：
[
{
name：Ruby Red
}，
{
name：Blue Ocean
}
]
}
class（我知道这里有问题）
class Location {
var name =
init（obj：tmp）{
self.name = tmp [name]
}
}
并且需要进行AlamoFire调用
Alamofire.request（.GET，https://www.domain.com/arc / v1 / api / metro_areas / 1，参数：nil）
.responseJSON {response in
如果让dataFromNetworking = response.result.value {
let metroLocations = dataFromNetworking [ metro_locations]
var位置：[位置] = []
为tmp在metroLocations为！ [Dictionary] {//< - not working，Generic Paramter'Key'无法推断
let location = Location.init（obj：tmp）
locations.append（location）
}
}
我已经包含错误msg，not工作，但感觉在其他部分也有问题（比如在初始化中期待一个字典）。 Key不能被推断是什么意思，还有其他需要修改的内容？
编辑＃1
$ b $我已经更新了我的位置，以反映您的建议：
init？（dictionary：[String：AnyObject] ）{
guard let id = dictionary [id] else {return nil}
guard let name = dictionary [name] else {return nil}
guard let latitude = 纬度] else {return nil}
guard let longitude = dictionary [longitude] else {return nil}
self.name = name as！ String
self.id = id as！ int
self.latitude =纬度为！双倍
self.longitude =经度为！ Double
}
但是我收到错误：
无法将类型NSNull（0x10f387600）的值转换为NSNumber（0x10f77f2a0）。
像这样：
我认为 guard 语句会阻止这种情况。我失踪了什么
您可以将 metroLocations 作为一个字典数组，即：
数组<字典< String，String>>
或者更简洁：
[[String：String]]
因此：
如果让dataFromNetworking = response.result.value {
guard let metroLocations = dataFromNetworking [metro_locations] as？ [[String：String]] else {
print（这不是字符串数组，其中所有的字符串都是字符串）
return
}
var locations = [位置]（）
在metroLocations中的字典{
如果let location =位置（字典：字典）{
locations.append（location）
}
}
其中
class Location {
let name：String
init？（dictionary：[String：String]）{
guard let name = dictionary [name] else {return nil}
self.name = name
}
}
显然，我使用 [[String：String]] 来表示一个字典的数组，其中的值都是字符串，如你的例子。如果值包含字符串（数字，布尔等）之外的对象，则可以使用 [[String：AnyObject]] 。
在您的修订版本中，您向我们展示了更完整的位置实现。您应该避免 as！强制投放，而是在 guard 语句：
class Location {
let id：Int
let name：String
允许纬度：Double
让经度：Double
init？（dictionary：[String：AnyObject]）{
guard let id = dictionary [id]如？ Int，
let name = dictionary [name] as？ String，
let latitude = dictionary [latitude] as？ Double，
让longitude = dictionary [longitude] as？ Double else {
return nil
}
self.name = name
self.id = id
self.latitude = latitude
self.longitude = longitude
}
}
I am not an iOS dev and have to make a few changes to a Swift / AlamoFire project (not mine) and am a bit lost.
I have the following JSON:
{"metro_locations":
[
{
"name":"Ruby Red"
},
{
"name":"Blue Ocean"
}
]
}
class (I know that there are issues here):
class Location{
var name=""
init(obj:tmp){
self.name=tmp["name"]
}
}
and need to make an AlamoFire call
Alamofire.request(.GET, "https://www.domain.com/arc/v1/api/metro_areas/1", parameters: nil)
.responseJSON { response in
if let dataFromNetworking = response.result.value {
let metroLocations = dataFromNetworking["metro_locations"]
var locations: [Location]=[]
for tmp in metroLocations as! [Dictionary] { // <- not working, Generic Paramter 'Key' could not be inferred
let location=Location.init(obj: tmp)
locations.append(location)
}
}
}
I have included the error msg, the "not working" but feel that there are issues in other parts too (like expecting a dictionary in the initialization). What does the 'Key' could not be inferred mean and are there other changes I need to make?
edit #1
I have updated my Location to this to reflect your suggestion:
init?(dictionary: [String: AnyObject]) {
guard let id = dictionary["id"] else { return nil }
guard let name = dictionary["name"] else { return nil }
guard let latitude = dictionary["latitude"] else { return nil }
guard let longitude = dictionary["longitude"] else { return nil }
self.name = name as! String
self.id = id as! Int
self.latitude = latitude as! Double
self.longitude = longitude as! Double
}
but I get the error:
Could not cast value of type 'NSNull' (0x10f387600) to 'NSNumber' (0x10f77f2a0).
like this:
I would think that the guard statement would prevent this. What am I missing?
You can cast metroLocations as an array of dictionaries, namely:
Array<Dictionary<String, String>>
Or, more concisely:
[[String: String]]
Thus:
if let dataFromNetworking = response.result.value {
guard let metroLocations = dataFromNetworking["metro_locations"] as? [[String: String]] else {
print("this was not an array of dictionaries where the values were all strings")
return
}
var locations = [Location]()
for dictionary in metroLocations {
if let location = Location(dictionary: dictionary) {
locations.append(location)
}
}
}
Where
class Location {
let name: String
init?(dictionary: [String: String]) {
guard let name = dictionary["name"] else { return nil }
self.name = name
}
}
Clearly, I used [[String: String]] to represent an array of dictionaries where the values were all strings, as in your example. If the values included objects other than strings (numbers, booleans, etc.), then you might use [[String: AnyObject]].
In your revision, you show us a more complete Location implementation. You should avoid as! forced casting, and instead us as? in the guard statements:
class Location {
let id: Int
let name: String
let latitude: Double
let longitude: Double
init?(dictionary: [String: AnyObject]) {
guard let id = dictionary["id"] as? Int,
let name = dictionary["name"] as? String,
let latitude = dictionary["latitude"] as? Double,
let longitude = dictionary["longitude"] as? Double else {
return nil
}
self.name = name
self.id = id
self.latitude = latitude
self.longitude = longitude
}
}
这篇关于可能将这个Alamofire的结果转化为一系列的字典的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！