Question

I’m trying to get the hang of using notifications. In my view controller class, I have a bool isFullScreen. When the value of this bool changes, I want to a notification to be sent to all observing classes. I’m not quite sure how to go about doing this, since a BOOL is not an object. How would I accomplish this?

Answer 1

[[NSNotificationCenter defaultCenter] postNotificationName:YourNotificationName object:[NSNumber numberWithBool:isFullScreen]]; //YourNotificationName is a string constant

KVO Example:

If you were to do it with KVO, it would be something like the below…. :

[self addObserver:self forKeyPath:@"isFullScreen" options:(NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld) context:nil];

- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
if ([keyPath isEqualToString: @"isFullScreen"]) {
        BOOL newValue = [[change objectForKey:NSKeyValueChangeNewKey] boolValue];
    }
}

//and in dealloc
[self removeObserver:self forKeyPath:@"isFullScreen" ];