我正在使用iOS Swift应用程序而我正在尝试获取网站的内容。问题是,当我运行代码时,在执行其他行之后返回响应对象。
我有这个:
public var response: Array<Any>?
public func myRequest(completion: @escaping (_ json: Any?, _ error: Error?)->()) {
var request = URLRequest(url: self.url)
request.httpBody = postString.data(using: .utf8)
let t = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data,
error == nil else {
completion(nil, error)
return
}
let json = try? JSONSerialization.jsonObject(with: data, options: [])
if let dictionary = json as? [String : Any] {
if (dictionary["ok"] as? String == "true") {
self.response = dictionary["users"] as? Array<Any>
}
}
completion(json, error)
}
t.resume()
}
然后:
func foo() {
myRequest() { json, error in
print(json)
}
print("I'm here!")
}
我得到了这个:
I'm here
{...} //JSON
问题是:为什么我在I'm here
之前检索JSON
?我该如何解决?
答案 0 :(得分:0)
以下是一个示例(基于您的代码),了解如何让myRequest接受完成块,并在反序列化(或不反馈)JSON后调用它。
public func myRequest(completion: @escaping (_ json: Any?, _ error: Error?)->())
{
var request = URLRequest(url: self.url)
request.httpBody = postString.data(using: .utf8)
let t = URLSession.shared.dataTask(with: request)
{ data, response, error in
guard let data = data,
error == nil else
{
completion(nil, error)
return
}
let json = try? JSONSerialization.jsonObject(with: data, options: [])
//Do other things
completion(json, error)
}
t.resume()
}
以下是你如何称呼它:
func foo()
{
myRequest()
{ json, error in
// will be called at either completion or at an error.
}
}
现在,如果你不是主线程,并且真的想等待你的myRequest()完成,那么就是这样的(有很多方法可以做到这一点,顺便说一句):
func foo()
{
let group = DispatchGroup()
group.enter()
myRequest()
{ json, error in
// will be called at either completion or at an error.
group.leave()
}
group.wait() // blocks current queue so beware!
}