NSNotificationCenter简单使用

1，添加监听 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(action:) name:@"A" object:nil];

2，发送通知,[[NSNotificationCenter defaultCenter] postNotificationName:@"A" object:nil];

3，执行方法
- (void)action:(NSNotification *)notification
}
}