我试图实现当对象更新时,Notificationcenter Post Message 应该触发并在通知观察者处接收。但就我而言,通知帖子位于一个控制器中,观察者位于另一个控制器中。
这是我从 webViewController 发布通知的代码:
if let jsonData = jsonString.data(using: .utf8) {
do {
let decoder = JSONDecoder()
let mainObject = try decoder.decode(DynamicTabsModel.self, from: jsonData)
print("tab model:::", mainObject)
let dataDict:[AnyObject] = mainObject.tabInfo.tabList as [AnyObject]
print("data object for tab", dataDict)
NotificationCenter.default.post(name: Notification.Name("updateParentViewController"), object: mainObject)
} catch {
print(error.localizedDescription)
}
}
这是 CreateCardViewController 的代码,我在其中接收通知观察者:
NotificationCenter.default.addObserver(self, selector: #selector(self.updateParentViewController(_:)), name: Notification.Name(rawValue: "updateParentViewController"), object: nil)
@objc func updateParentViewController(_ notification: NSNotification){
if let receivedData = notification.object as? DynamicTabsModel {
//use received data
print("recieved back data:::", receivedData)
for d in receivedData.tabInfo.tabList {
print(d.label )
self.tabMenuAry.append(d.label)
}
initCarbonKitTab()
NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: "updateParentViewController"), object: nil)
print("tab menu array::", self.tabMenuAry)
}
}
我的问题是,每当对象模型发生更改时,它都应该触发通知 post 方法,并且它应该接收观察者。
我尝试在viewdidload、viewdidappear和viewwillappear中调用通知观察者。什么也没收到。
任何帮助,非常感谢...
确保您的视图控制器已注册观察者。分享我的代码,运行良好。我在 viewDidLoad 中添加了观察者。您可以在其他ViewController中调用fetchDate来传递该观察者中的流。
import Foundation
import UIKit
// MARK: - Observers
class MyViewController: UIViewController {
override func viewDidLoad() {
addObservers()
}
deinit {
removeObservers()
}
@objc func notificationAction() {
}
}
// MARK:- APIHandler
extension MyViewController {
func fetchData() {
// Call API when you get success response, post notification
// NotificationCenter.default.post(name: NSNotification.Name(rawValue: NOTIFICATION_NAME.MY_NOTIFICATION), object: nil)
}
}
extension MyViewController {
func addObservers(){
NotificationCenter.default.addObserver(
self,
selector: #selector(notificationAction),
name: NSNotification.Name(rawValue: NOTIFICATION_NAME.MY_NOTIFICATION) ,
object: nil
)
}
func removeObservers(){
NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue:NOTIFICATION_NAME.MY_NOTIFICATION), object: nil)
}
}
enum NOTIFICATION_NAME{
static let MY_NOTIFICATION = "myNotification"
}
从您的
viewDidLoad()
调用这些方法
NotificationCenter.default.addObserver(
self,
selector: #selector(appDidEnterBackground),
name: UIApplication.didEnterBackgroundNotification,
object: nil
)
NotificationCenter.default.addObserver(
self,
selector: #selector(appWillEnterForeground),
name: UIApplication.willEnterForegroundNotification,
object: nil
)
// This code is executed when the app goes to the background
@objc func appDidEnterBackground() {
//
}
// This code is executed when the app goes to the foreground
@objc func appWillEnterForeground() {
//
}
你的视图控制器是该通知的观察者吗?
如果没有:
NotificationCenter.default.addObserver(self, selector: #selector(myactionWhenReceivePost()), name: NSNotification.Name(rawValue: "updateParentViewController"), object: nil)
@objc func myactionWhenReceivePost() {
}
答案更新后编辑:
当您添加观察者时,如果您注册了对象参数,则它需要等于发送通知的对象。就像
Notification.Name
一样,如果不相等,您将不会收到任何通知。
此外:将操作的参数从
NSNotification
更改为 Notification
,因为我认为你正在使用 Swift 5.0
如果您想传递数据,请使用以
[AnyHashable:Any]?
作为输入的 userInfo:
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "updateParentViewController"), object: nil, userInfo: yourDictionary)
并在你的行动中:
@objc func myactionWhenReceivePost(_ notification: Notification) {
guard let myObject = notification.userInfo?["myObject"] as? MyObject else {return }
}
好了,因为您已经知道如何注册和取消注册通知,所以让我们从通知中获取自定义 userInfo
首先使用自定义用户信息发布通知:
let customUserInfo: [AnyHashable: Any] = ["value": YOUR_CUSTOM_OBJECT]
NotificationCenter.default.post(name: .myNotificationName, object: nil, userInfo: customUserInfo)
现在,当您想捕获此通知并需要该信息时,请在接收器控制器中使用此信息
@objc func onNotificationCatched(notification:NSNotification) {
let userInfo:Dictionary<String, YOUR_CUSTOM_OBJECT > = notification.userInfo as! Dictionary<String, YOUR_CUSTOM_OBJECT>
let value = userInfo["value"]! as YOUR_CUSTOM_OBJECT
print(value)
}
在接收器控制器的viewDidLoad中使用这个
NotificationCenter.default.addObserver(self, selector: #selector(onNotificationCatched(notification:)), name: .myNotificationName, object: nil)
为了方便使用 NSNotifications Name ,请进行扩展
extension NSNotification.Name {
static let myNotificationName = NSNotification.Name(rawValue: "My-Custom-Notification_String-Name")
}