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
Related
The documentation says "The notification's object is the completed PayPalPayment, same as the delegate method."
But I still don't get it. This is how I add the notification:
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(payPalCompletionHandler:)
name:PayPalTransactionDidSucceedNotification
object:nil];
-(void)payPalCompletionHandler:(NSNotification *) notification
{
// How do I get (PayPalPayment *)completedPayment?
}
Answering my own question, duh.
use this to get the notifications object.
NSDictionary *myObject = [notification object];
hello i assign nsnotifiaction in app delegate.m's method and this method call eprox every 30sec, and i wants its notifcation in viewcontroller adn execute method,
here is my code of appdelegate .m
- (void)layoutAnimated:(BOOL)animated{
BOOL yy= self.bannerView.bannerLoaded;
if (yy==1){
self.iAdString=[NSMutableString stringWithString:#"1"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"BannerViewActionWillBegin" object:self];
}
else{
self.iAdString=[NSMutableString stringWithString:#"0"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"BannerViewActionDidFinish" object:self];
}
}
and in viewcontroller.m
//i defined in viewdidload method
- (void)viewDidLoad{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(willBeginBannerViewActionNotification:) name:#"BannerViewActionWillBegin "object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(didFinishBannerViewActionNotification:) name:#"BannerViewActionDidFinish" object:nil];
}
its method are..
- (void)willBeginBannerViewActionNotification:(NSNotification *)notification{
[self.view addSubview:self.app.bannerView];
NSLog(#"come");
}
- (void)didFinishBannerViewActionNotification:(NSNotification *)notification {
NSLog(#"come");
[self.app.bannerView removeFromSuperview];
}
- (void)dealloc{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
I have not getting response of excessing method while method read in appdelegate file.
Please help me.
You have a typo error.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(willBeginBannerViewActionNotification:) name:#"BannerViewActionWillBegin "object:nil];
//Your error here-------------------------------------------------------------------------------------------------------------------------------------^
You have put a space there.
SideNote: For all notification names, you should/can create a separate file and put all your notification names as constants strings.
const NSString *kBannerViewActionWillBegin=#"BannerViewActionWillBegin";
this will be easier to change the value and no such typo will happen.
From your code what I get is except for the notification name's all other stuff is fine, did you check whether the notification gets fired. Try keeping break points at the notification firing line.
I want to send object to selector in NSNotification.I mean, I have 3 buttons and on click of each button I am registering notification and when that event occurred I am calling one selector and in that selector I want to find out which button user has clicked because I have common action for all 3 buttons.
-(void)allThreeButtonAction:(sender)id
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(performSomeOperationWhenEventOccur) name:#"EventCompletedNotification" object:nil];
}
//Some event occurred, so I am sending notification
[[NSNotificationCenter defaultCenter] postNotificationName:#"EventCompletedNotification" object:nil];
//Notified method
-(void)performSomeOperationWhenEventOccur
{
//Here I want to know which button is pressed.
}
I hope I am clear.
You may want to look at postNotificationName:object:userInfo: from NSNotificationCenter documentation
You simply send a UserInfo containing whatever you need to identify the button (easiest is the pointer to the button) that you retrieve in your selector.
Your selector signature should receive the notification:
- (void)performSomeOperationWhenEventOccur:(NSNotification*) notification:(NSNotification*) notification
{
// Use [notification userInfo] to determine which button was pressed...
}
Don't forget to modify the selector name when your register it:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(performSomeOperationWhenEventOccur:) name:#"EventCompletedNotification" object:nil];
You can't pass an object when adding a notification observer, so you'll have to store the button that was pressed somewhere:
-(void)allThreeButtonAction:(id)sender
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(performSomeOperationWhenEventOccur) name:#"EventCompletedNotification" object:nil];
self.buttonPressed = sender;
}
Then you can just read it in your notification handler:
-(void)performSomeOperationWhenEventOccur
{
if ( self.buttonPressed = self.button1 )
...
}
Below Snippet will help you.
Button1
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(performSomeOperationWhenEventOccur:) name:#"button1" object:button1];
Button2
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(performSomeOperationWhenEventOccur:) name:#"button2" object:button2];
Change method to following
- (void) performSomeOperationWhenEventOccur:(NSNotification *) notification
{
if ([[notification name] isEqualToString:#"button1"])
{
NSButton *button1=[notification button1];
NSLog (#"Successfully received the test notification! from button1");
}
else
{
NSButton *button2=[notification button2];
NSLog (#"Successfully received the test notification! from button2");
}
}
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 trying to get one instance of using NSNotificationCenter with addObserver and postNotificationName but I can't work out why it won't work.
I have 2 lines to code to add the observer and send the message in 2 different classes
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(newEventLoaded:) name:#"Event" object:nil];
and
[[NSNotificationCenter defaultCenter]postNotificationName:#"Event" object:self];
If I set the name to nil it works fine becuase it's just a broadcast, when i try and define a notification name the messages never get through.
All my code makes use of NSNotifications like so:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(updateView) name:#"ScanCompleted" object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:#"ScanCompleted" object:nil];
The first one is registering the notification and the second posting of the notification.
Basically it's all to do with the order of execution. If you've executed postNotificationName before addObserver, then this is an easy problem to have. Use breakpoints and step through the code :)
Your first breakpoint should stop here:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(updateView:) name:#"ScanCompleted" object:nil];
Then here:
[[NSNotificationCenter defaultCenter]postNotificationName:#"ScanCompleted" object:self];
Also, make sure the selector has a colon on. Because it's method signature will be:
- (void)updateView:(NSNotification *)notification;
I had the same problem.
The reason is that I called removeObserver method at
- (void)viewDidDisappear:(BOOL)animated{
NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
[notificationCenter removeObserver:self];
}
So check whether if you had called removeObserver before postNotification.
Tips: You can search the keyword "removeObserver" to find if you had called this function.
Change this:
[[NSNotificationCenter defaultCenter]postNotificationName:#"Event" object:self];
to this:
[[NSNotificationCenter defaultCenter]postNotificationName:#"Event" object:nil];
If your first notification is registered properly, newEventLoaded should be called.
I had a similar issue and my problem was due to the notification being called on another thread. This solved my problem.
dispatch_async(dispatch_get_main_queue(),^{
[[NSNotificationCenter defaultCenter]postNotificationName:#"Event" object:self];
});
Have you tried any other names but #"Event" and nil? Just to be sure, you could define your event names in one file and include that into both notification registration and sending. For example:
Header file:
extern NSString * const NOTE_myEventName;
Source file:
NSString * const NOTE_myEventName = #"MyEventName";
Registration:
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(handleMyEvent:)
name:NOTE_myEventName
object:nil];
Notification sending:
[[NSNotificationCenter defaultCenter]
postNotificationName:NOTE_myEventName object:nil];
I successfully fixed my "NSNotification not being sent when postNotificationName: called" crash.
I found the real bug is in notification message handler.
The postNotificationName and addObserver are all right as the first post of this thread.