nsnotificationcenter

问题 why do I get "wait_fences: failed to receive reply" for this code? Is it the way I'm using notification to communicate back to the main thread? #import "ViewController.h" @implementation ViewController @synthesize alert; #pragma mark - Background Thread Test Methods - (void) ConfigTasksForBackground:(id)sender{ NSLog(@"ConfigTasksForBackground - Starting"); [NSThread sleepForTimeInterval:6]; [[NSNotificationCenter defaultCenter] postNotificationName:@"ModelChanged" object:self]; NSLog(@

问题 why do I get "wait_fences: failed to receive reply" for this code? Is it the way I'm using notification to communicate back to the main thread? #import "ViewController.h" @implementation ViewController @synthesize alert; #pragma mark - Background Thread Test Methods - (void) ConfigTasksForBackground:(id)sender{ NSLog(@"ConfigTasksForBackground - Starting"); [NSThread sleepForTimeInterval:6]; [[NSNotificationCenter defaultCenter] postNotificationName:@"ModelChanged" object:self]; NSLog(@

问题 Hey guys I have a C++ class that I recently renamed from *.cpp to *.mm to support objective-c. So I can add the following objective-c code. [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notificationHandler:) name:@"notify" object:nil]; How do/Can I write the notificationHandler method in c++? Will setting addObserver:self property work? 回答1: You'd need an Objective-C class to handle Objective-C notifications. Core Foundation to the rescue! In.. wherever you start

问题 Hey guys I have a C++ class that I recently renamed from *.cpp to *.mm to support objective-c. So I can add the following objective-c code. [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notificationHandler:) name:@"notify" object:nil]; How do/Can I write the notificationHandler method in c++? Will setting addObserver:self property work? 回答1: You'd need an Objective-C class to handle Objective-C notifications. Core Foundation to the rescue! In.. wherever you start

问题 I have had a simple UIView block animation that handles animating a group of text fields into view when the keyboard will show (and animate them back when the keyboard hides). This has worked fine in iOS 6 & 7, but now I'm getting incorrect behavior, and it all points to some change in UIKeyboardWillShowNotification . I set up an isolated project to test this further on a single text field, with two buttons that call exactly the same methods that are fired for the keyboard's WillShow and

问题 I want to set alarm for selected days of the week. It may be a weekday (mon, tue, wed, thu, or fri), weekend(sat, sun) or daily. How can i do this using local notifications? 回答1: If you have the time which you have to fire notification every day, you should do this NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; NSDateComponents *components = [[NSDateComponents alloc] init]; for (NSMutableArray * arrDay in self.namaztimes) { NSLog(@"Alarm Array: %@"

问题 I am working in swift, I want to refresh a page so I am sending it using notification, I am posting a notification in one ViewController and adding observer in another and it is working perfectly. What I want to do is add unit test to it in swift. I checked many sites but was not able to do it. I am new to swift and don't know where to start. Basically the working is, when i click the button notification is posted and when the next view controller is loaded the notification observer is added.

问题 Given that objects may be deallocated even while a method invocation is in progress (link) *, is it safe for an object to register for and receive notifications that will be delivered on a thread that is different from the one on which it expects to be deallocated? For reference, the documentation states that In a multithreaded application, notifications are always delivered in the thread in which the notification was posted, which may not be the same thread in which an observer registered

问题 Let's say a user has a messages app on their iPhone and iPad. They get a new message from the server, so a push notification is sent to both their devices. Now the user picks up their iPhone and reads the message waiting in notification center. How do I now remove the message from notification center (and the app badge number) on their iPad, since it's already been read? 回答1: When the user reads the message on the iPhone (presumably after tapping on the notification or the launch icon of the

问题 In an app that uses a NSStatusItem with a custom view like this: ... how can you get notifications when: The status bar gets hidden because of a full screen app The status item moves position because another item is added/removed/resized? Both are necessary to move the custom view to the right position when the item changes places. 回答1: There is a method -[NSStatusItem setView:] . When you set a custom view for your status item, this view is automatically inserted into a special status bar