Swift 2 – UnsafeMutablePointer到对象
发布时间:2020-12-14 05:54:19 所属栏目:百科 来源:网络整理
导读:如果我有一个方法如: func someMethod(contextPtr: UnsafeMutablePointerVoid) 如何从contextPtr获取对象? func someMethod(contextPtr: UnsafeMutablePointerVoid){ let object:MyObject = contextPtr.memory} 得到: ‘Void’ is not convertible to ‘M
如果我有一个方法如:
func someMethod(contextPtr: UnsafeMutablePointer<Void>) 如何从contextPtr获取对象? func someMethod(contextPtr: UnsafeMutablePointer<Void>){ let object:MyObject = contextPtr.memory } 得到:
什么是秘密酱 更多详情: 我在这里实际做的是为SCNetworkReachability设置全局回调函数: func callback(reachability:SCNetworkReachability,flags: SCNetworkReachabilityFlags,info: UnsafeMutablePointer<Void>) { let r:Reachability = info.memory } 然后添加回调如下: var context = SCNetworkReachabilityContext(version: 0,info: nil,retain: nil,release: nil,copyDescription: nil) var s = self withUnsafeMutablePointer(&s) { context.info = UnsafeMutablePointer($0) } SCNetworkReachabilitySetCallback(reachability,callback,&context)
这应该工作:将对象指针传递为不透明的非托管指针
回调: context.info = UnsafeMutablePointer(Unmanaged.passUnretained(myObject).toOpaque()) SCNetworkReachabilitySetCallback(reachability,&context) 并通过以下方式在回调中检索: func callback(reachability:SCNetworkReachability,info: UnsafeMutablePointer<Void>) { let myObject = Unmanaged<MyObject>.fromOpaque(COpaquePointer(info)).takeUnretainedValue() } 当然,这假设有一些对该对象的强烈引用存在 更新:请注意,从对象指针到void指针的转换 context.info = unsafeAddressOf(myObject) // ... myObject = unsafeBitCast(info,MyObject.self) 生成的汇编代码 – 就我所见 – 相同。 更新2:另请参阅How to cast self to UnsafeMutablePointer<Void> type in swift了解更多信息 Swift 3更新(Xcode 8 beta 6): var context = SCNetworkReachabilityContext(version: 0,copyDescription: nil) context.info = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque()) // ... func callback(reachability:SCNetworkReachability,info: UnsafeMutableRawPointer?) { if let info = info { let myObject = Unmanaged<MyObject>.fromOpaque(info).takeUnretainedValue() // ... } } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |