我试图将对象从我的应用程序委托传递到另一个类的通知接收器。

我想传递整数messageTotal。现在我有：

在接收器中：

- (void) receiveTestNotification:(NSNotification *) notification
{
    if ([[notification name] isEqualToString:@"TestNotification"])
        NSLog (@"Successfully received the test notification!");
}

- (void)viewDidLoad {
    [super viewDidLoad];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(dismissSheet) name:UIApplicationWillResignActiveNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveTestNotification:) name:@"eRXReceived" object:nil];

在执行通知的类中：

[UIApplication sharedApplication].applicationIconBadgeNumber = messageTotal;
[[NSNotificationCenter defaultCenter] postNotificationName:@"eRXReceived" object:self];

但是我想将对象传递messageTotal给另一个类。

您必须使用“ userInfo”变体，并传递一个包含messageTotal整数的NSDictionary对象：

NSDictionary* userInfo = @{@"total": @(messageTotal)};

NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
[nc postNotificationName:@"eRXReceived" object:self userInfo:userInfo];

在接收端，您可以按以下方式访问userInfo字典：

-(void) receiveTestNotification:(NSNotification*)notification
{
    if ([notification.name isEqualToString:@"TestNotification"])
    {
        NSDictionary* userInfo = notification.userInfo;
        NSNumber* total = (NSNumber*)userInfo[@"total"];
        NSLog (@"Successfully received test notification! %i", total.intValue);
    }
}

在提供的解决方案基础上，我认为展示一个传递您自己的自定义数据对象的示例可能会有所帮助（根据问题，我在这里将其称为“消息”）。

A类（发送者）：

YourDataObject *message = [[YourDataObject alloc] init];
// set your message properties
NSDictionary *dict = [NSDictionary dictionaryWithObject:message forKey:@"message"];
[[NSNotificationCenter defaultCenter] postNotificationName:@"NotificationMessageEvent" object:nil userInfo:dict];

B类（接收器）：

- (void)viewDidLoad
{
    [super viewDidLoad];
    [[NSNotificationCenter defaultCenter]
     addObserver:self selector:@selector(triggerAction:) name:@"NotificationMessageEvent" object:nil];
}

#pragma mark - Notification
-(void) triggerAction:(NSNotification *) notification
{
    NSDictionary *dict = notification.userInfo;
    YourDataObject *message = [dict valueForKey:@"message"];
    if (message != nil) {
        // do stuff here with your message data
    }
}

Swift 2版本

正如@约翰·卡尔森（Johan Karlsson）指出的那样……我做错了。这是使用NSNotificationCenter发送和接收信息的正确方法。

首先，我们看一下postNotificationName的初始化程序：

init(name name: String,
   object object: AnyObject?,
 userInfo userInfo: [NSObject : AnyObject]?)

资源

我们将使用userInfo参数传递信息。该[NSObject : AnyObject]类型是保持在从Objective-C的。因此，在Swift领域中，我们所需要做的就是传入一个Swift字典，该字典具有从中派生的键NSObject和可以AnyObject。

有了这些知识，我们创建了一个字典，并将其传递给object参数：

 var userInfo = [String:String]()
 userInfo["UserName"] = "Dan"
 userInfo["Something"] = "Could be any object including a custom Type."

然后，将字典传递到对象参数中。

发件人

NSNotificationCenter.defaultCenter()
    .postNotificationName("myCustomId", object: nil, userInfo: userInfo)

接收器类别

首先，我们需要确保我们的班级正在观察通知

override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("btnClicked:"), name: "myCustomId", object: nil)   
}
    

然后我们可以收到我们的字典：

func btnClicked(notification: NSNotification) {
   let userInfo : [String:String!] = notification.userInfo as! [String:String!]
   let name = userInfo["UserName"]
   print(name)
}

斯威夫特5

func post() {
    NotificationCenter.default.post(name: Notification.Name("SomeNotificationName"), 
        object: nil, 
        userInfo:["key0": "value", "key1": 1234])
}

func addObservers() {
    NotificationCenter.default.addObserver(self, 
        selector: #selector(someMethod), 
        name: Notification.Name("SomeNotificationName"), 
        object: nil)
}

@objc func someMethod(_ notification: Notification) {
    let info0 = notification.userInfo?["key0"]
    let info1 = notification.userInfo?["key1"]
}

奖金（您一定要这样做！）：

替换Notification.Name("SomeNotificationName")为.someNotificationName：

extension Notification.Name {
    static let someNotificationName = Notification.Name("SomeNotificationName")
}

更换"key0"并"key1"用Notification.Key.key0和Notification.Key.key1：

extension Notification {
  enum Key: String {
    case key0
    case key1
  }
}

我为什么一定要这样做？为避免代价高昂的拼写错误，请重命名，查找使用情况等。

Swift 5.1自定义对象/类型

// MARK: - NotificationName
// Extending notification name to avoid string errors.
extension Notification.Name {
    static let yourNotificationName = Notification.Name("yourNotificationName")
}


// MARK: - CustomObject
class YourCustomObject {
    // Any stuffs you would like to set in your custom object as always.
    init() {}
}

// MARK: - Notification Sender Class
class NotificatioSenderClass {

     // Just grab the content of this function and put it to your function responsible for triggering a notification.
    func postNotification(){
        // Note: - This is the important part pass your object instance as object parameter.
        let yourObjectInstance = YourCustomObject()
        NotificationCenter.default.post(name: .yourNotificationName, object: yourObjectInstance)
    }
}

// MARK: -Notification  Receiver class
class NotificationReceiverClass: UIViewController {
    // MARK: - ViewController Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()
        // Register your notification listener
        NotificationCenter.default.addObserver(self, selector: #selector(didReceiveNotificationWithCustomObject), name: .yourNotificationName, object: nil)
    }

    // MARK: - Helpers
    @objc private func didReceiveNotificationWithCustomObject(notification: Notification){
        // Important: - Grab your custom object here by casting the notification object.
        guard let yourPassedObject = notification.object as? YourCustomObject else {return}
        // That's it now you can use your custom object
        //
        //

    }
      // MARK: - Deinit
  deinit {
      // Save your memory by releasing notification listener
      NotificationCenter.default.removeObserver(self, name: .yourNotificationName, object: nil)
    }




}