所以我想要的是一个可能会在函数中传递给它的闭包的类,它也可能在某个时候想要忽略闭包。如何检查闭包变量是否已设置,并且可以在完成后删除它?可选闭包并检查它是否
不能调用 '!=' 类型的参数列表 '(@lvalue(sucsess: 布尔!,产品:[AnyObject]) - >()?NilLiteralConvertible)' 类型“(sucsess :Bool !,产品:[AnyObject]!) - >()?'不符合 协议“NilLiteralConvertible”
class someClass{
//typealias completionHandlerClosureType = (sucsess:Bool!, items:[AnyObject]!)->()
var completionHandler:(sucsess:Bool!, items:[AnyObject]!)->()?
var hitpoints = 100
var someset = ["oh no!","avenge me!"]
init(){}
func getHitFunc(impact:Int, passedCompletionsHandler:(sucsess:Bool!, items:[AnyObject]!)->()){
completionHandler = passedCompletionsHandler
hitpoints = hitpoints - impact
}
func checkIfDead{
if hitpoints<=0 { // The error received
if completionHandler != nil{// Cannot invoke '!=' with an argument list of type
//'(@lvalue (sucsess: Bool!, products: [AnyObject]!) ->()?, NilLiteralConvertible)'
//run the handler if dead
completionHandler(sucsess: true, items: someset)
//do not run it again
completionHandler = nil //Type '(sucsess: Bool!, products: [AnyObject]!) ->()?' does not conform to protocol 'NilLiteralConvertible'
}
}
else{
completionHandler = nil //Type '(sucsess: Bool!, products: [AnyObject]!) ->()?' does not conform to protocol 'NilLiteralConvertible'
}
}
}
类型别名是伟大的解决方案 – Yitzchak 2017-03-06 15:26:24