ios - 将字典键传递给 CFDictionaryGetValue

Question

由于 Swift 中的 UnsafePointer，我感到头疼。

这是我要调用的方法:

func CFDictionaryGetValue(theDict: CFDictionary!, _ key: UnsafePointer<Void>) -> UnsafePointer<Void>

我就是这样做的。

 let ds: SCDynamicStoreRef = SCDynamicStoreCreate(nil, "setNet" as CFString, nil, nil)!


let list = SCDynamicStoreCopyProxies(ds)

print(list!)
print(CFDictionaryGetValue(list, UnsafePointer("HTTPPort")))

但是这会返回一个错误。我不知道如何将字典键传递给这个方法。如果我删除 UnsafePointer("HTTPPort") 并使用 "HTTPPort" 代替，我会收到运行时错误。"

如何访问字典值？

Answer 1

最简单的解决方案是利用免费桥接在 CFDictionary 和 NSDictionary 之间，并使用 NSDictionary访问器方法:

let ds = SCDynamicStoreCreate(nil, "setNet", nil, nil)!

if let list = SCDynamicStoreCopyProxies(ds) as NSDictionary? {
    if let port = list[kSCPropNetProxiesHTTPPort as NSString] as? Int {
        print("HTTPPort:", port)
    }
}

但只是为了完整起见:可以用CFDictionaryGetValue:

if let list = SCDynamicStoreCopyProxies(ds)  {
    let key = kSCPropNetProxiesHTTPPort
    let port = unsafeBitCast(CFDictionaryGetValue(list, unsafeAddressOf(key)), NSObject!.self)
    if port != nil {
        print("HTTPPort:", port)
    }
}