在Swift 3中将NSData转换为NSString？

我有一个函数返回某些系统值。它在Swift 2.2中运行良好，我刚刚升级到Xcode 8和Swift 3，现在它失败了。在Swift 3中将NSData转换为NSString？

func ioPlatExpertDevString(_ property: String) -> String { 
    // Start tapping in to the IO Service 
    let ioPlatformExpertDevice:io_service_t? = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("IOPlatformExpertDevice")) 

    var sAnswer = "Not Found" 
    let cfAnswer:AnyObject! = IORegistryEntryCreateCFProperty(ioPlatformExpertDevice!, "\(property)" as CFString!, kCFAllocatorDefault, 0).takeRetainedValue() 
    if (cfAnswer != nil) { 
     let nsAnswer = (cfAnswer as! NSString) 
     sAnswer = nsAnswer.uppercased 
    } 

    // Close the IO Service 
    IOObjectRelease(ioPlatformExpertDevice!) 

    return sAnswer 
}

之前，我在使用“CFData”而不是“AnyObject”。它建立正常，但在运行时，我得到以下错误：

Could not cast value of type '__NSCFData' (0x7fff7b833ec0) to 'NSString' (0x7fff7ac32038).

来源

2016-09-21 user2625833

对于其财产，你调用该函数？ –

请不要不注释类型除非编译器告诉你这样做。

例如IOServiceGetMatchingService返回一个非可选io_service_t，您的可选注释使情况变得更糟。

IORegistryEntryCreateCFProperty返回Unmanaged<CFTypeRef>!不需要注释以及字符串插值和转换为隐式解包可选。

CFTypeRef可以桥接到本机Swift类型。

如果返回类型是(NS)Data它最不可能在以前的版本中工作。

如果后者可以转换为String，则此代码考虑String和Data。

func ioPlatExpertDevString(_ property: String) -> String { 
    // Start tapping in to the IO Service 
    let ioPlatformExpertDevice = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("IOPlatformExpertDevice")) 

    var sAnswer = "Not Found" 
    let cfAnswer = IORegistryEntryCreateCFProperty(ioPlatformExpertDevice, property as CFString, kCFAllocatorDefault, 0).takeRetainedValue() 
    if let cfData = cfAnswer as? Data, let answer = String(data:cfData, encoding:.utf8) { 
    sAnswer = answer.uppercased() 
    } else if let answer = cfAnswer as? String { 
    sAnswer = answer.uppercased() 
    } 
    // Close the IO Service 
    IOObjectRelease(ioPlatformExpertDevice) 
    return sAnswer 
}

来源

2016-09-21 15:30:34 vadian

更换

let nsAnswer = (cfAnswer as! NSString)

要

let nsAnswer = NSString(data: cfAnswer as! Data, encoding: String.Encoding.utf8.rawValue)

来源

2016-10-21 13:43:55

在Swift 3中将NSData转换为NSString？

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