Question

我正在使用Swift向Objective-C app添加新功能。

我在Objective-C（registration.m）中有这个观察者：

[[NSNotificationCenter defaultCenter] removeObserver:self name:NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(confirmSms) name:NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS object:nil];

并在confirm.m中：

[[NSNotificationCenter defaultCenter] postNotificationName:NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS object:nil];

如何在Swift中观察到这一点？我试过了

NotificationCenter.default.removeObserver(self,
                                                  name: NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS,
                                                  object:nil);

NotificationCenter.default.addObserver(self,
                                              selector:#selector(self.confirmationSmsSent),
                                              name: NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS,
                                              object: nil);

我正在接受

使用未解析的标识符 'NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS'

由于

//编辑：

我在Obj-C中声明：

NSString *const NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS = @"confirmationSMSSent";

这仍然适用于此吗？

let name: NSNotification.Name = NSNotification.Name("Your_Notification_Name_Key_String") //NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS

当我使用

时

NotificationCenter.default.addObserver(self, selector:#selector(self.confirmationSmsSent(_:)), name: name, object: nil)

func confirmationSmsSent(notification: NSNotification) {

}

我收到了错误

'MyController'类型的值没有成员'confirmationSmsSent'

on

NotificationCenter.default.addObserver（self，selector：#selector（self.confirmationSmsSent（_ :)），name：name，object：nil）

Answer 1

在Swift 3中，语法发生了变化。您必须定义NSNotification.Name

的变量

let name: NSNotification.Name = NSNotification.Name("Your_Notification_Name_Key_String") //NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS

//Add Notification
NotificationCenter.default.addObserver(self, selector:#selector(self.yourSelector(_:)), name: name, object: nil)

//Remove Notification Observer
NotificationCenter.default.removeObserver(self, name: name, object: nil)

//Your Selector
func yourSelector(_ notification: Notification) {
//Code
}

Answer 2

这是因为您尚未声明NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS。

通常，通知名称只是一个字符串，顺便说一句，您必须将其强制转换为嵌套的NSNotification.Name类型。

let NOTIFICATION_SERVER_SENT_CONFIRMATION_SMS = NSNotification.Name("<some string>")

Answer 3

最有用的swift - lije代码是扩展名

extension Notification.Name {
static let someNewName = "ThatsItImAwsome" 
}

帖子内的用法：

.someNewKey

这样：

NotificationCenter.default.addObserver(self, selector:#selector(self.yourSelector(_:)), name: .someNewKey, object: nil)

Objective-C观察者 - 如何在Swift中使用

3 个答案: