iOS消息通知Notification的用法

1.发送消息

 NSNotification *notification = [NSNotification notificationWithName:@"selectPosition" object:nil userInfo:@"codeABC" forKey:@"code"];
2 [[NSNotificationCenter defaultCenter]postNotification:notification];

2.接收消息

 - (void)viewDidLoad {
     [super viewDidLoad];
     [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(selectPosition:) name:@"selectPosition" object:nil];
 }

 - (void)selectPosition:(NSNotification *)notification
 {
     NSString *code = [notification.userInfo objectForKey:@"code"];
 }