@H_301_1@在使用
Swift的Xcode 6和7的早期版本中,这种语法可以工作：
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,在Xcode 7 beta 4中,SecItemCopyMatching声明已更改：
OLD：func SecItemCopyMatching(_ query：CFDictionary,_ result：UnsafeMutablePointer< AnyObject？>) – > OSStatus
新：func SecItemCopyMatching(_ query：CFDictionary！,_ result：UnsafeMutablePointer< Unmanaged< AnyObject>？>) – > OSStatus
…现在secureItemValue类型不匹配.
在提取结果之前,这个机制很混乱,我希望新声明在某种程度上更容易,但我不知道如何为secureItemValue变量声明正确的类型并提取结果.
解决方法
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
}
