postNotificationName is not yet trigger in appdelegate class

Question

In Appdelegate.m added postNotification method

   - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {

         if(application.applicationState == UIApplicationStateBackground) {

[[NSNotificationCenter defaultCenter] postNotificationName: @"SuggetionPushNotification" object:nil userInfo:userInfo];


              AppDelegate *appDel = (AppDelegate *)[[UIApplication sharedApplication] delegate];

                        SideMenuViewController *leftMenuViewController = [[SideMenuViewController alloc] init];
                        MFSideMenuContainerViewController *container = [MFSideMenuContainerViewController
                                                                        containerWithCenterViewController:[[UINavigationController alloc]
                                                                                                           initWithRootViewController:[[SuggetionViewController alloc] init]]
                                                                        leftMenuViewController:leftMenuViewController
                                                                        rightMenuViewController:Nil];

                         [self.window makeKeyAndVisible];
                        appDel.window.rootViewController = container;

                 }


                    }

ViewController B (SuggetionViewController) In viewDidLoad

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



- (void) receiveTestNotification:(NSNotification *) notification {
    NSLog(@"working");

}

But here not yet fire Notification, if added both post and addobserver in same class then only it fire. what wrong i made. I referred from Send and receive messages through NSNotificationCenter in Objective-C? Please help

Refer this link http://stackoverflow.com/questions/4577255/nsnotification-postnotificationname-in-appdelegate-but-nsnotificationcenter-in-v might help you — Shangari C, May 18 '16 at 09:58

score 2 · Answer 1 · answered May 18 '16 at 09:44

2

Your View Controller B is not in memory when you are posting the notification thats why Controller B is unable to observe the notification. Add Delay before posting the notification will help.

double delayInSeconds = 2.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
  [[NSNotificationCenter defaultCenter] postNotificationName: @"SuggetionPushNotification" object:nil userInfo:nil];

});

answered May 18 '16 at 09:44

Jasmeet Kaur

1,538
14
16

Can you check ViewController B is in memory when you are posting the notification? Can you debug it? – Jasmeet Kaur May 18 '16 at 09:55
why its not in memory , its not showing AppDelegate * 0x7fe2caf1ba50 0x00007fe2caf1ba50 delayInSeconds double 2 popTime dispatch_time_t 19116090692644 _baseUrl NSString * nil 0x0000000000000000 – Joyal Clifford May 18 '16 at 10:01
Is ViewController B is a root view controller? It should be root view controller or loaded in the memory to observe the Notification – Jasmeet Kaur May 18 '16 at 10:22
appDel.window.rootViewController = container; – Joyal Clifford May 18 '16 at 10:41

score 0 · Answer 2 · answered May 18 '16 at 09:42

0

You're calling your notification from the launch method in the app delegate before any view/viewcontroller hierarchy has a change to instantiate and load. The reason you are not getting the notification is because your SuggetionViewController has not been instantiated yet. If you want the notification to be received, you need to fire it after the view controller gets a change to be created.

answered May 18 '16 at 09:42

Danny Bravo

4,534
1
25
43

after loading SuggetionViewController also it will not yet add observer will not fire. – Joyal Clifford May 18 '16 at 09:47
What can do Please suggest – Joyal Clifford May 18 '16 at 09:51

score 0 · Answer 3 · answered May 18 '16 at 11:51

You can't receive notification inside your SuggetionViewController if it's now loaded.
You add the observer in the viewDidLoad so it can happens that you recieve a remote notification while the SuggetionViewController is not loaded.

You should ensure that your controller is loaded before processing notifications.

jjpp · Answer 4 · 2016-05-18T12:55:19.173

Your 'SuggetionViewController' object is not initialized when you post the notification. So there is no 'SuggetionViewController' object to catch the notification.

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo{
if(application.applicationState == UIApplicationStateBackground) {

    AppDelegate *appDel = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    SideMenuViewController *leftMenuViewController = [[SideMenuViewController alloc] init];
    SuggetionViewController *sug_controller = [[SuggetionViewController alloc] init]];
    [sug_controller registerNotification];

    [[NSNotificationCenter defaultCenter] postNotificationName: @"SuggetionPushNotification" object:nil userInfo:userInfo];
    MFSideMenuContainerViewController *container = [MFSideMenuContainerViewController containerWithCenterViewController:[[UINavigationController alloc] initWithRootViewController:sug_controller leftMenuViewController:leftMenuViewController rightMenuViewController:Nil];
    [self.window makeKeyAndVisible];
    appDel.window.rootViewController = container;
}
}

Add the following instance method to SuggetionViewController

- (void)registerNotification
 {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveTestNotification:) name:@"SuggetionPushNotification" object:nil];
 }

- (void)receiveTestNotification
  {
        NSlog(@"Notification recieved-->>>");
  }

So if i did SuggetionViewController *newObject=[SuggetionViewController new]; — Joyal Clifford, May 18 '16 at 12:26
ViewDidload method will not get called right after the object allocation. Please fire the notification from appdelegate using a timer after a delay(1 or 2 secs) — jjpp, May 18 '16 at 12:31
@JoyalClifford You can try the above code. Before adding any code inside receiveTestNotification method just check if the code working by adding a log inside the method. — jjpp, May 18 '16 at 12:57

Santo · Answer 5 · 2016-05-18T12:39:22.520

In your AppDelegate implementation add this

static void displayStatusChanged(CFNotificationCenterRef center, void *observer,
                             CFStringRef name, const void *object,
                             CFDictionaryRef userInfo) {
if (name == CFSTR("com.apple.springboard.lockcomplete")) {
    [[NSUserDefaults standardUserDefaults] setBool:YES
                                            forKey:@"kDisplayStatusLocked"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}
}

In applicationDidFinishLaunchingWithOptions, add this below code

CFNotificationCenterAddObserver(
                                CFNotificationCenterGetDarwinNotifyCenter(), NULL, displayStatusChanged,
                                CFSTR("com.apple.springboard.lockcomplete"), NULL,
                                CFNotificationSuspensionBehaviorDeliverImmediately);

Post it in your didRecieveRemoteNotification method.

     [[NSNotificationCenter defaultCenter]postNotificationName:@"TestNotification" object:self];

Post this in your view controller viewDidLoad method.

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

Then it will trigger this method.

 - (void) receiveTestNotification:(NSNotification *) notification
   {

    if ([[notification name] isEqualToString:@"TestNotification"]) {
    NSLog (@"Successfully received the test notification!");

      }
   }

@JoyalClifford please try the above code once, have edited and checked it is working fine, hope it will help you... — Santo, May 18 '16 at 12:39

postNotificationName is not yet trigger in appdelegate class

5 Answers5