NSNotificationCenter中出現問題

Question

從不調用NSNotificationCenter選擇器方法。

PostNotification是遵循：

- (IBAction)go:(id)sender { 
AnotherViewController *obj = [self.storyboard instantiateViewControllerWithIdentifier:@"AnotherViewController"]; 

[[NSNotificationCenter defaultCenter] 
postNotificationName:@"TestNotification" 
object:self]; 




[self.navigationController pushViewController:obj animated:YES]; 

} 

在AnotherViewController.m遵守通知：

- (void)viewDidLoad { 
[super viewDidLoad]; 

[[NSNotificationCenter defaultCenter] addObserver:self 
             selector:@selector(receiveTestNotification:) 
              name:@"TestNotification" 
              object:nil]; 


// Do any additional setup after loading the view. 
    } 

和receiveTestNotification是：

- (void) receiveTestNotification:(NSNotification *) notification 
{ 


if ([[notification name] isEqualToString:@"TestNotification"]) 
    NSLog (@"Successfully received the test notification!"); 
} 

問題是什麼？謝謝

Answer 1

您應該將添加觀察者方法移動到視圖控制器的初始化。因爲您在AnotherViewController註冊自己以接收通知之前發佈通知。

- (instancetype)initWithCoder:(NSCoder *)aDecoder 
    { 
     self = [super initWithCoder:aDecoder]; 
     if (self) { 
      [[NSNotificationCenter defaultCenter] addObserver:self 
                selector:@selector(receiveTestNotification:) 
                 name:@"TestNotification" 
                 object:nil]; 
     } 
     return self; 
    }