您必须使用“ userInfo”变量并传递一个包含 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，您可以按如下方式访问 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);
}
}

在提供的解决方案的基础上，我认为展示一个传递自定义数据对象的示例可能会有所帮助(我在这里按照问题将其称为“ message”)。

甲类(寄件人) :

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(接收机) :

- (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 Version 迅捷2版本

正如@Johan Karlsson 指出的... ... 我做错了。以下是使用 NSNotificationCenter 发送和接收信息的正确方法。

首先，我们查看 postNotificationName 的初始化程序:

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

来源

我们将使用 userInfo参数传递信息。[NSObject : AnyObject]类型是从 目标 C保留下来的。因此，在 Swift 领域，我们所需要做的就是传递一个 Swift 字典，其中包含从 NSObject派生的键和可以是 AnyObject的值。

根据这些知识，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."

然后我们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)
}

Swift 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"]
}

额外奖励(你绝对应该这么做!) :

用 .someNotificationName代替 Notification.Name("SomeNotificationName"):

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

用 Notification.Key.key0和 Notification.Key.key1代替 "key0"和 "key1":

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

为什么我一定要这样做? 为了避免代价高昂的错误，享受重命名，享受找到使用等..。

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)
}








}