iPhone NSNotification
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NSNotification allows objects to communicate with each other asynchronously. Object A can post a notification, which is broadcast to the NSNotificationCenter. The Notification Center will then forward the notification to any observers, like Object B, that registered for that notification. Object B can define a selector method to handle being passed the notification. Notifications are a useful way for objects to communicate without needing direct references to each other.
![MyObjB ”hoge” popupAlert
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(popupAlert:)
name:@”hoge”
object:nil];
MyObjB
addObserver
NSNotificationCenter](https://image.slidesharecdn.com/iphonensnotification-100209081741-phpapp02/85/iPhone-NSNotification-7-320.jpg)
![MySendObj ”hoge”
// NSNotification
NSNotification* notification = [NSNotification notificationWithName: @”hoge”
object:self userInfo:nil];
//
[[NSNotificationCenter defaultCenter] postNotification:notification];
“Hoge”
NSNotificationCenter MySendObj
postNotification](https://image.slidesharecdn.com/iphonensnotification-100209081741-phpapp02/85/iPhone-NSNotification-8-320.jpg)
![NSNotificationCenter MyObjB
popupAlert
-(void)popupAlert:(NSNotification *)notification {
//
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sample"
message:@” ”
delegate:self
cancelButtonTitle:@"OK"
otherButtonTitles: nil];
[alert show];
[alert release];
}
MyObjB
“Hoge”
NSNotificationCenter](https://image.slidesharecdn.com/iphonensnotification-100209081741-phpapp02/85/iPhone-NSNotification-9-320.jpg)
![removeObserver
- (void)dealloc {
// Notification
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
MyObjB
removeObserver
NSNotificationCenter](https://image.slidesharecdn.com/iphonensnotification-100209081741-phpapp02/85/iPhone-NSNotification-10-320.jpg)
iPhone NSNotification
- 2. • NSNotification • • • • •
- 3. • NSNotification • NSNotificationCenter • • / MyObjB NSNotification MyObjA NSNotificationCenter MySendObj MyObjC
- 4. • • • MyObjB “Hoge” “Hoge” MyObjA NSNotificationCenter MySendObj MyObjC ”foo”
- 5. • NSNotificationCenter • / • ” ” • • NSNotification userInfo(NSDictionary) release MyObjB MyObjA NSNotificationCenter MySendObj MyObjC
- 6. • • • •
- 7. MyObjB ”hoge” popupAlert [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(popupAlert:) name:@”hoge” object:nil]; MyObjB addObserver NSNotificationCenter
- 8. MySendObj ”hoge” // NSNotification NSNotification* notification = [NSNotification notificationWithName: @”hoge” object:self userInfo:nil]; // [[NSNotificationCenter defaultCenter] postNotification:notification]; “Hoge” NSNotificationCenter MySendObj postNotification
- 9. NSNotificationCenter MyObjB popupAlert -(void)popupAlert:(NSNotification *)notification { // UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sample" message:@” ” delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil]; [alert show]; [alert release]; } MyObjB “Hoge” NSNotificationCenter
- 10. removeObserver - (void)dealloc { // Notification [[NSNotificationCenter defaultCenter] removeObserver:self]; } MyObjB removeObserver NSNotificationCenter