Swift里通知的使用NSNotificationCenter

1.控制器viewDidLoad方法里注册通知

override func viewDidLoad() {
        super.viewDidLoad()

        // 3.注册通知，监听菜单
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(HomeTableViewController.change), name: PopoverAnimatorWillShow, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(HomeTableViewController.change), name: PopoverAnimatorWillDismiss, object: nil)
    }

2.通知调用的change方法

/**
     修改标题按钮状态
     */
    func change(){
        let titleBtn = navigationItem.titleView as! TitleButton
        titleBtn.selected = !titleBtn.selected
    }

3.移除通知

 deinit{
        // 移除通知
        NSNotificationCenter.defaultCenter().removeObserver(self)
    }

4.通知是如何发送的

let PopoverAnimatorWillShow = "PopoverAnimatorWillShow"
let PopoverAnimatorWillDismiss = "PopoverAnimatorWillDismiss"

 // 发送通知,通知控制器即将展开
        NSNotificationCenter.defaultCenter().postNotificationName(PopoverAnimatorWillShow, object: self)

// 发送通知,通知控制器即将消失
        NSNotificationCenter.defaultCenter().postNotificationName(PopoverAnimatorWillDismiss, object: self)