传值B页面:
[NSNotificationCenter defaultCenter] postNotificationName:@"cityName" object:self userInfo:dict];
接收A页面:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(cityNameNotification:) name:@"cityName" object:nil];
- (void)cityNameNotification:(NSNotification *)notification {
NSDictionary *nameDictionAry = [notification userInfo];
[backButton setTitle:[nameDictionAry objectForKey:@"State"] forState:UIControlStateNormal];
}