ReactiveCocoaDelegateExample

DelegateExample.m

- (void)viewDidLoad {
    UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame: CGRectZero];
    self.searchController = [[UISearchDisplayController alloc] initWithSearchBar:self.searchBar contentsController:self];
    self.searchController.delegate = self;
    // Place it in view
    searchBar.delegate = self;
}

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)text {
    self.searchResults = [self search: text];
}

- (void)searchDisplayControllerDidBeginSearch:(UISearchDisplayController *)searchController {
    self.isSearching = YES;
}

- (void)searchDisplayControllerDidEndSearch:(UISearchDisplayController *)searchController {
    self.isSearching = NO;
}

SignalPattern.m

- (void)viewDidLoad {
  UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame: CGRectZero];
  self.searchController = [[UISearchDisplayController alloc] initWithSearchBar:self.searchBar contentsController:self];
  RAC(self, searchResults) = [self rac_liftSelector:@selector(search:) withSignals:self.searchBar.rac_textSignal, nil];
  RAC(self, searching) = [[self.searchController rac_isActiveSignal] doNext:^(id x) {
      NSLog(@"Searching %@", x);
  }];
}

UISearchBarRAC.m

@implementation UISearchBar (RAC)
- (RACSignal *)rac_textSignal {
    self.delegate = self;
    RACSignal *signal = objc_getAssociatedObject(self, _cmd);
    if (signal != nil) return signal;
    
    /* Create signal from selector */
    signal = [[self rac_signalForSelector:@selector(searchBar:textDidChange:) 
                    fromProtocol:@protocol(UISearchBarDelegate)] map:^id(RACTuple *tuple) {
        return tuple.second;
    }];
    
    objc_setAssociatedObject(self, _cmd, signal, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    return signal;
}
@end

UISearchDisplayControllerRAC.m

@implementation UISearchDisplayController (RAC)
- (RACSignal *)rac_isActiveSignal {
    self.delegate = self;
    RACSignal *signal = objc_getAssociatedObject(self, _cmd);
    if (signal != nil) return signal;
    
    /* Create two signals and merge them */
    RACSignal *didBeginEditing = [[self rac_signalForSelector:@selector(searchDisplayControllerDidBeginSearch:) 
                                        fromProtocol:@protocol(UISearchDisplayDelegate)] mapReplace:@YES];
    RACSignal *didEndEditing = [[self rac_signalForSelector:@selector(searchDisplayControllerDidEndSearch:) 
                                      fromProtocol:@protocol(UISearchDisplayDelegate)] mapReplace:@NO];
    signal = [RACSignal merge:@[didBeginEditing, didEndEditing]];
    
    
    objc_setAssociatedObject(self, _cmd, signal, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    return signal;
}
@end