有关的类

1. NSNotification
2. NSNotificationCenter

NSNotification

NSNotification实例将对象发送到NSNotificationCenter,并由NSNotificationCenter将通知发送出去

首先需要注册观察这对象:

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
    [center addObserver:self selector:@selector(notifi) name:@"Maweiyi" object:nil];
}

发送通知:

- (IBAction)btnClick:(id)sender {
    
    
    NSString *string = @"This is a good man";
    NSNotification *notification = [[NSNotification alloc] initWithName:@"Maweiyi" object:string userInfo:nil];
    
    [[NSNotificationCenter defaultCenter] postNotification:notification];
}

- (void)notifi {
    NSLog(@"我接收到通知了1");
}