Objective c 与来自swift的目标c关联对象存储交互

我正在尝试创建一个实用程序，将闭包添加为uicontrol的事件处理程序。尽管我有几个问题，下面是代码：

public func addCallBack(callback: Void -> Void, forControlEvents events: UIControlEvents)
{   
    var optClosureDict = objc_getAssociatedObject(self, &UIControlClosureDictKey) as? Dictionary<UInt, Set<ClosureWrapper>>

    if optClosureDict == nil {
        optClosureDict = Dictionary<UInt, Set<ClosureWrapper>>()
    }

    var closureDict = optClosureDict!

    if closureDict[events.rawValue] == nil {
        closureDict[events.rawValue] = Set<ClosureWrapper>()
    }

    var closures = closureDict[events.rawValue]!

    let wrapper = ClosureWrapper(callback:callback)
    addTarget(wrapper, action:"invoked", forControlEvents: events)
    closures.insert(wrapper)

    objc_setAssociatedObject(self, &UIControlClosureDictKey, optClosureDict!, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    var res = objc_getAssociatedObject(self, &UIControlClosureDictKey) as? Dictionary<UInt, Set<ClosureWrapper>>
}

public func addCallBack（回调：Void->Void，forControlEvents事件：UIControlEvents）
{   
var optclosredict=objc_getAssociatedObject（self，&UIControlClosureDictKey）as？字典
如果optclosredict==nil{
optclosredict=字典（）
}
var closureDict=optClosureDict！
如果closureDict[events.rawValue]==nil{
closureDict[events.rawValue]=Set（）
}
var closures=closureDict[events.rawValue]！
let wrapper=closurewapper（回调：回调）
addTarget（包装器，操作：“已调用”，forControlEvents:events）
闭包.插入（包装器）
objc_setAssociatedObject（self，&UIControlClosureDictKey，OptClosRedict！，.objc_ASSOCIATION_RETAIN_Non原子）
var res=objc_getAssociatedObject（self，&UIControlClosureDictKey）as？字典
}

1） 这两个if语句看起来都很难看，我调用了一个返回可选值的API，如果它为nil，我想用一些默认值覆盖它，那么我必须强制将其展开。有没有更惯用的“更快”的方法

---

2） 另外，当我创建一个closureDict时，它有一个int到闭包的键值对，然后我使用setAssociatedObject存储它，然后我在getAssociatedObject中检索到的内容会返回一个包含0个键值对的字典。发生了什么事？这是一个问题，因为我的closureWrapper没有被保留，而且整个东西都不工作

您可以简化行：

var optClosureDict = objc_getAssociatedObject(self, &UIControlClosureDictKey) as? Dictionary<UInt, Set<ClosureWrapper>>

if optClosureDict == nil {
    optClosureDict = Dictionary<UInt, Set<ClosureWrapper>>()
}

var closureDict = optClosureDict!

--

此外，以下代码不符合您的预期：

var closures = closureDict[events.rawValue]!

let wrapper = ClosureWrapper(callback:callback)
addTarget(wrapper, action:"invoked", forControlEvents: events)
closures.insert(wrapper)

问题在于

Set

是一个

struct

，与

类不同，它不是一个“引用”类型。因此，
var closures=…
行正在创建
集的新副本，而不是引用原始副本。因此，您正在更新
集合的副本，而不是引用
closureDict
中的副本

完成后，您可以更新
closureDict
：

var closures = closureDict[events.rawValue]!

let wrapper = ClosureWrapper(callback:callback)
addTarget(wrapper, action:"invoked", forControlEvents: events)
closures.insert(wrapper)

closureDict[events.rawValue] = closures

或者更简单地说，就地更新：

let wrapper = ClosureWrapper(callback:callback)
addTarget(wrapper, action:"invoked", forControlEvents: events)
closureDict[events.rawValue]!.insert(wrapper)

--

因此，这将产生以下替代方案：

func addCallBack(callback: Void -> Void, forControlEvents events: UIControlEvents) {
    var closureDict = objc_getAssociatedObject(self, &UIControlClosureDictKey) as? ClosureDict ?? ClosureDict()

    if closureDict[events.rawValue] == nil {
        closureDict[events.rawValue] = Set<ClosureWrapper>()
    }

    let wrapper = ClosureWrapper(callback:callback)
    addTarget(wrapper, action:"invoked", forControlEvents: events)
    closureDict[events.rawValue]!.insert(wrapper)

    objc_setAssociatedObject(self, &UIControlClosureDictKey, closureDict, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}

func addCallBack（回调：Void->Void，forControlEvents事件：UIControlEvents）{
var closureDict=objc_getAssociatedObject（self，&uicontrol closuredictkey）作为？closureDict？？closureDict（）
如果closureDict[events.rawValue]==nil{
closureDict[events.rawValue]=Set（）
}
let wrapper=closurewapper（回调：回调）
addTarget（包装器，操作：“已调用”，forControlEvents:events）
closureDict[events.rawValue]！.insert（包装器）
objc_setAssociatedObject（self，&UIControlClosureDictKey，closureDict，.objc_ASSOCIATION_RETAIN_Non原子）
}

或

func addCallBack（回调：Void->Void，forControlEvents事件：UIControlEvents）{
var closureDict=objc_getAssociatedObject（self，&uicontrol closuredictkey）作为？closureDict？？closureDict（）
var closures=closureDict[events.rawValue]？？Set（）
let wrapper=closurewapper（回调：回调）
addTarget（包装器，操作：“已调用”，forControlEvents:events）
闭包.插入（包装器）
closureDict[events.rawValue]=闭包
objc_setAssociatedObject（self，&UIControlClosureDictKey，closureDict，.objc_ASSOCIATION_RETAIN_Non原子）
}
谢谢，回答得很好
var closures = closureDict[events.rawValue]!

let wrapper = ClosureWrapper(callback:callback)
addTarget(wrapper, action:"invoked", forControlEvents: events)
closures.insert(wrapper)

closureDict[events.rawValue] = closures

let wrapper = ClosureWrapper(callback:callback)
addTarget(wrapper, action:"invoked", forControlEvents: events)
closureDict[events.rawValue]!.insert(wrapper)

func addCallBack(callback: Void -> Void, forControlEvents events: UIControlEvents) {
    var closureDict = objc_getAssociatedObject(self, &UIControlClosureDictKey) as? ClosureDict ?? ClosureDict()

    if closureDict[events.rawValue] == nil {
        closureDict[events.rawValue] = Set<ClosureWrapper>()
    }

    let wrapper = ClosureWrapper(callback:callback)
    addTarget(wrapper, action:"invoked", forControlEvents: events)
    closureDict[events.rawValue]!.insert(wrapper)

    objc_setAssociatedObject(self, &UIControlClosureDictKey, closureDict, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}

func addCallBack(callback: Void -> Void, forControlEvents events: UIControlEvents) {
    var closureDict = objc_getAssociatedObject(self, &UIControlClosureDictKey) as? ClosureDict ?? ClosureDict()

    var closures = closureDict[events.rawValue] ?? Set<ClosureWrapper>()

    let wrapper = ClosureWrapper(callback:callback)
    addTarget(wrapper, action:"invoked", forControlEvents: events)
    closures.insert(wrapper)

    closureDict[events.rawValue] = closures

    objc_setAssociatedObject(self, &UIControlClosureDictKey, closureDict, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}