code examples for http://jonsterling.github.com/2010/03/28/advanced-blocks-in-objective-c.html

Example1.m

@interface RootViewController (Actions)
- (void)_goBack:sender;
- (void)_goForward:sender;
@end

@implementation RootViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  
  // ...
  
  self.previousButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRewind
                                                                          target:self
                                                                          action:@selector(_goBack:)];
  self.nextButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFastForward
                                                                      target:self
                                                                      action:@selector(_goForward:)];
  [self.previousButtonItem release];
  [self.nextButtonItem release];
  
  // ...
                                                                        
}

@end

@implementation RootViewController (Actions)

- (void)_goBack:sender {
  self.date = [self.date dateByAddingDays:-1];
  [self.tableView reloadData];
  [self.statusView reload];
}

- (void)_goForward:sender {
  self.date = [self.date dateByAddingDays:1];
  [self.tableView reloadData];
  [self.statusView reload];
}

@end

Example2.m

@interface RootViewController (Actions)
- (void)_changeDate:sender;
@end

@implementation RootViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  
  // ...
  
  self.previousButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRewind
                                                                          target:self
                                                                          action:@selector(_changeDate:)];
  self.nextButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFastForward
                                                                      target:self
                                                                      action:@selector(_changeDate:)];
  [self.previousButtonItem release];
  [self.nextButtonItem release];
  
  // ...
                                                                        
}

@end

@implementation RootViewController (Actions)

- (void)_changeDate:sender {
  NSInteger delta = 0;
  if ([sender isEqual:self.previousButtonItem]) {
    delta = -1;
  } else if ([sender isEqual:self.nextButtonItem]) {
    delta = 1;
  }
  
  self.date = [self.date dateByAddingDays:delta];
  [self.tableView reloadData];
  [self.statusView reload];
}

@end

Example3.m

@implementation RootViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  
  // ...
  
  self.previousButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRewind block:^() {
    self.date = [self.date dateByAddingDays:-1];
    [self.tableView reloadData];
    [self.statusView reload];
  }];
    
  self.nextButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFastForward block:^() {
    self.date = [self.date dateByAddingDays:1];
    [self.tableView reloadData];
    [self.statusView reload];
  }];
  
  [self.previousButtonItem release];
  [self.nextButtonItem release];
  
  // ...
                                                                        
}

@end

Example4.m

typedef void (^JSVoidBlock)();

@implementation RootViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  
  // ...
  
  JSVoidBlock (^changeDateByDaysBlk)(int) = ^ JSVoidBlock (int days) {
    return
      [[^ {
          self.date = [self.date dateByAddingDays:days];
          [self.tableView reloadData];
          [self.statusView reload];
        } copy] autorelease];
  };
  
  self.previousButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRewind
                                                                           block:changeDateByDaysBlk(-1)];
    
  self.nextButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFastForward
                                                                       block:changeDateByDaysBlk(1)];

  [self.previousButtonItem release];
  [self.nextButtonItem release];
  
  // ...
                                                                        
}

@end