單例
import Foundation
class NetWorkingTools:NSObject {
// func == -
// class func == +
// 方法一:
/*
static var onceToken: dispatch_once_t = 0;
static var _instance: NetworkTools?
class func shareNetworkTools() -> NetworkTools {
print(onceToken)
dispatch_once(&NetworkTools.onceToken, {
_instance = NetworkTools()
})
return _instance!
}
*/
// 方法二:
/*
static let _instance: NetworkTools = NetworkTools()
class func shareNetworkTools() -> NetworkTools {
return _instance
}
override init() {
print("++++++")
}
*/
// 方法三:
// 如果在Swift中編寫單例, 推薦使用如下寫法
// 而且蘋果有統一的命名規範, 但凡是單例統一是用shareInstance
static let shareInstance: NetWorkingTools = NetWorkingTools()
}