如何在Xcode 7 beta 4中调用SecItemCopyMatching？

在以前的Swift版本的Xcode 6和7中，这个语法可以工作：

var secureItemValue: Unmanaged<AnyObject>? let statusCode: OSStatus = SecItemCopyMatching(keychainItemQuery, &secureItemValue) if statusCode == errSecSuccess { let opaquePointer = secureItemValue?.toOpaque() let secureItemValueData = Unmanaged<NSData>.fromOpaque(opaquePointer!).takeUnretainedValue() // Use secureItemValueData... } 

但是，Xcode 7 beta 4中的SecItemCopyMatching声明已经更改：

OLD： func SecItemCopyMatching(_ query: CFDictionary, _ result: UnsafeMutablePointer<AnyObject?>) -> OSStatus

NEW： func SecItemCopyMatching(_ query: CFDictionary!, _ result: UnsafeMutablePointer<Unmanaged<AnyObject>?>) -> OSStatus

…和现在的secureItemValuetypes不匹配。

该机制之前提取结果混淆，我希望它是在某种程度上更容易与新的声明，但我不知道如何声明正确的types为secureItemValuevariables，并提取结果。

Answer 1

这适用于Xcode 7 beta 4

 var dataTypeRef: AnyObject? let status: OSStatus = withUnsafeMutablePointer(&dataTypeRef) { SecItemCopyMatching(keychainQuery as CFDictionaryRef, UnsafeMutablePointer($0)) } if status == noErr { return dataTypeRef as? NSData } else { return nil } 

Answer 2

根据这个答案，你可以删除Unmanaged<>围绕AnyObject：

 var secureItemValue: AnyObject? let statusCode: OSStatus = SecItemCopyMatching(keychainItemQuery, &secureItemValue)