I try to call Notification for another class
// Which is in ClassA
- (void)onDidFinishLaunchingNotification:(NSNotification*)notification
{
NSLOG(#"onDidFinishLaunchingNotification");
}
calling notification from another class
// Which is in Class B
[[NSNotificationCenter defaultCenter]addObserver:nil selector:#selector(onDidFinishLaunchingNotification:) name:nil object:nil];
In Class A, add self as an observer of the notification with a name
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(onDidFinishLaunchingNotification:)
name:YourOnDidFinishLaunchingNotificationName
object:nil];
and in Class B, use -postNotificationName:object: to post the notification:
[[NSNotificationCenter defaultCenter] postNotificationName:YourOnDidFinishLaunchingNotificationName
object:nil];
in Class B you shuold addObserver to B like this :
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(onDidFinishLaunchingNotification:)
name:YourOnDidFinishLaunchingNotificationName
object:nil];
I think you should to look at the document of the addObserver:selector:name:object:
and here is a very useful example for using NSNotification
Related
I have an ARC enabled project
There are few observers added in viewDidLoad
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(getSipNotification:) name:#"getSipNotification" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(syncExtensionData:) name:#"syncExtensionData" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(showLocalNotification:) name:#"showLocalNotification" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(outgoingCall:) name:#"outgoingCall" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(playRingtone) name:#"playRingtone" object:nil];
I want to remove all observers so I added following line in viewDidUnload
[[NSNotificationCenter defaultCenter] removeObserver:self];
Now my question is, is this remove all observers?
If not how can do it?
UPDATE
If I want to remove a single observer how can do it?
Can you help me please.
Yes, It will remove all observers.
[[NSNotificationCenter defaultCenter] removeObserver:self];
And you can remove a particular observer like this...
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"syncExtensionData" object:nil];
In my application i used this notification :
for particular observer remove this way :
-(void)viewWillAppear:(BOOL)animated
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(deviceRotatedFeedBackView:) name:UIDeviceOrientationDidChangeNotification object:nil];
}
-(void)deviceRotatedFeedBackView:(NSNotification*)notification
{
//right whetever you want
}
- (void)viewWillDisappear:(BOOL)animated
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceOrientationDidChangeNotification object:nil];
}
may be it will helpful to you.
Yes it'll remove all the observers in your class.
You can use following to remove single observer:
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"getSipNotification" object:nil];
To remove individual observer.
viewDidUnload is deprecated in iOS6 and later, so Your observer never be removed from notification center in iOS6 and later. To remove single observer try
- (void)removeObserver:(id)notificationObserver name:(NSString *)notificationName object:(id)notificationSender
I added a notification with the following code,
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(videoLoadingComplete)
name:MPMovieNaturalSizeAvailableNotification
object:self.streamPlayer];
but it did not enter in the videoLoadingComplete function even after the video stars playing.
You can use following code
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(moviestart:) name:MPMoviePlayerLoadStateDidChangeNotification object:nil];
-(void)moviestart
{
//your code here
}
I am trying to call a method within an uiview from AppDelegate using the NSNotificationCenter to no avail..
AppDelegate.m
[[NSNotificationCenter defaultCenter] postNotificationName:#"ProcessDidComplete" object:items];
Then via MainStoryboard, the main view is loaded which controller class is MainViewController
in MainViewController.h viewDidLoad i have
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(ProcessDidComplete:) name:#"ProcessDidComplete" object:nil];
and then the method
- (void) ProcessDidComplete:(NSNotification *)pNotification
but it never gets called.
Thanks for any help!
just change a way..
First add observer
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(ProcessDidComplete:) name:#"ProcessDidComplete" object:nil];
Then Post Notification
[[NSNotificationCenter defaultCenter] postNotificationName:#"ProcessDidComplete" object:items];
Finally remove in viewWillDisappear
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"ProcessDidComplete" object:nil];
Your code looks okay, which makes me wonder where in your app delegate you post the notification?
If you post the notification before you add the observer in the view controlller, then the notification will never be received. Can you not send the message to the main view controller directly, i.e., as a property, rather than using notifications?
Just wanted to note here that iOS notification names are case-sensitive:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(handUpdate:) name:#"scheduleUpdated" object:nil];
will not respond to:
[[NSNotificationCenter defaultCenter] postNotificationName:#"ScheduleUpdated" object:items];
(as I spent the last 20 minutes figuring out...)
In one of my classes I post a notification:
[[NSNotificationCenter defaultCenter] postNotificationName:#"ALERTNOTI" object:self userInfo:nil];
In my app delegaate I listen:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(myMethod) name:#"ALERTNOTI" object:nil];
I use NSLog to track when I send and when the method myMethod gets called.
The method is not getting called despite me sending out the notification.
Is there something that I need to know about NSNotification? Is it tempermental?
do this changes
[[NSNotificationCenter defaultCenter] postNotificationName:#"ALERTNOTI" object:nil];
if you want to pass some object through the notification. then do this
ex: you want to pass an NSDictionary *dict
[[NSNotificationCenter defaultCenter] postNotificationName:#"ALERTNOTI" object:nil userInfo:dict];
the method you want to call via notification should be like this.
-(void)method:(NSNotification *) notif
{
// your code here.
//if you want to access your dict
NSDictionary *myDict=[notif userInfo];
}
Try this:
[[NSNotificationCenter defaultCenter] postNotificationName:#"ALERTNOTI" object:nil];
I'm sending a notification using:
[[NSNotificationCenter defaultCenter] postNotificationName:#"historyLoaded" object:jsonReturn];
And receiving the notification using:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(manageHistory:) name:#"historyLoaded" object:nil];
Then the method in the selector is:
- (void) manageHistory: (NSNotification *) historyData{
NSLog(#"this bit of code was run");
}
For some reaason the notification doesn't get through. Can notifications be send and received from anywhere in the app?
The object parameter in postNotification should be filled with an object which is "sending" the notification, or nil if the sender is not necessarily specified.
If you want to pass some information along, you should use postNotificationName:object:userInfo and put the information in userInfo dictionary instead.
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(manageHistory) name:#"historyLoaded" object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:#"historyLoaded"
object:nil userInfo:jsonReturn];
- (void) manageHistory: (NSNotification *) historyData{
NSDictionary* _dict = historyData.userInfo;
NSLog(#"Your information embedded to dictiuonary obj %#",_dict);
}
NOTE : Make sure your historyData should be a dictionary object in postNotificationName