xcode Swift：如何将闭包作为函数参数传入
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/26632129/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Swift: How to pass in a closure as a function argument
提问by Jeef
I'm trying to figure out the syntax for passing in a closure (completion handler) as an argument to another function.
我试图找出将闭包（完成处理程序）作为参数传递给另一个函数的语法。
My two functions are:
我的两个功能是：
Response Handler:
响应处理程序：
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)")
}
Query Function
查询功能
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:
我想将查询修改为：
public fund queryAllFlightsWithClosure( <CLOSURE>) {
so that I can externally pass the closure into the function. 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...
这样我就可以从外部将闭包传递给函数。我知道有一些对训练闭包的支持，但我不确定这是否也是可行的方法。我似乎无法正确理解语法......
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
采纳答案by Jeef
OOPS nevermind...
哎呀没关系...
public func queryAllFlightsWithClosure(completionHandler : (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void ) {
took out the {} and it seems to work?
取出 {}，它似乎工作？
回答by Antonio
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”且更具可读性：
public func queryAllFlightsWithClosure(completionHandler : MyClosure ) {
}
However, just replace MyClosurewith what it is aliasing, and you have the right syntax:
但是，只需将MyClosure其替换为别名，您就有正确的语法：
public func queryAllFlightsWithClosure(completionHandler : (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void ) {
}
