[英]Swift: How to pass in a closure as a function argument
I'm trying to figure out the syntax for passing in a closure (completion handler) as an argument to another function. 我试图找出传递一个闭包(完成处理程序)作为另一个函数的参数的语法。
My two functions are: 我的两个职能是:
func responseHandler(response: NSURLResponse!, data: NSData!, error: NSError!) -> Void {
var err: NSError
var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
println("AsSynchronous\(jsonResult)")
}
public func queryAllFlightsWithClosure( ) {
queryType = .AllFlightsQuery
let urlPath = "/api/v1/flightplan/"
let urlString : String = "http://\(self.host):\(self.port)\(urlPath)"
var url : NSURL = NSURL(string: urlString)!
var request : NSURLRequest = NSURLRequest(URL: url)
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue(), completionHandler:responseHandler)
}
I'd like to modify the Query to something like: 我想将Query修改为:
public fund queryAllFlightsWithClosure( <CLOSURE>) {
so that I can externally pass the closure into the function. 这样我就可以从外部将闭包传递给函数了。 I know there is some support for training closures but I"m not sure if thats the way to go either. I can't seem to get the syntax correct... 我知道有一些关于训练闭包的支持,但我不确定这是否也是如此。我似乎无法使语法正确...
I've tried: 我试过了:
public func queryAllFlightsWithClosure(completionHandler : {(response: NSURLResponse!, data: NSData!, error: NSError!) -> Void} ) {
but it keeps giving me an error 但它一直给我一个错误
It might help defining a type alias for the closure: 它可能有助于为闭包定义类型别名:
public typealias MyClosure = (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void
that makes the function signature "lighter" and more readable: 这使得函数签名“更轻”,更具可读性:
public func queryAllFlightsWithClosure(completionHandler : MyClosure ) {
}
However, just replace MyClosure
with what it is aliasing, and you have the right syntax: 但是,只需将MyClosure
替换为别名,并使用正确的语法:
public func queryAllFlightsWithClosure(completionHandler : (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void ) {
}
OOPS nevermind... OOPS没关系......
public func queryAllFlightsWithClosure(completionHandler : (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void ) {
took out the {} and it seems to work? 取出{}它似乎有用吗?
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