Observing SPSearch with KVO

gistfile1.m

// In the header

@property (nonatomic, strong) SPSearch *search;

// In the implementation

@synthesize search;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [self addObserver:self forKeyPath:@"search.searchInProgress" options:0 context:nil];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if ([keyPath isEqualToString:@"search.searchInProgress"]) {
        if (self.search.searchInProgress)
            NSLog(@"Search running");
        else
            NSLog(@"Search not running.");
    }
}

-(IBAction)doSearch:(id)sender {
    // This will only work if the session is logged in.
    self.search = [SPSearch searchWithSearchQuery:@"Hello" inSession:[SPSession sharedSession]];
}