AppDelegate 没有响应 NSNotification

Question

我想使用我应用的 AppDelegate 发布 CRToast 通知

这是我添加观察者的方式。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(noConnectionNotification)
                                                 name:@"No_Connection_Available" object:nil];

}

这是它应该调用的方法

-(void)noConnectionNotification{
     NSLog(@"received notification");
    NSString *notificationString = @"Unable to reach server. Changes will be cached.";
    NSDictionary *options = @{kCRToastTextKey : notificationString,
                              kCRToastNotificationTypeKey : @(CRToastTypeStatusBar),
                              kCRToastTextAlignmentKey : @(NSTextAlignmentCenter),
                              kCRToastBackgroundColorKey : [UIColor redColor],
                              kCRToastAnimationInDirectionKey : @(CRToastAnimationDirectionTop),
                              kCRToastAnimationOutDirectionKey : @(CRToastAnimationDirectionTop),
                              kCRToastTimeIntervalKey : @(2),
                              };
    [CRToastManager showNotificationWithOptions:options
                                completionBlock:nil];
}

以及我如何发布来自不同班级的通知：

 dispatch_async(dispatch_get_main_queue(), ^{
       [[NSNotificationCenter defaultCenter] postNotificationName:@"No_Connection_Available" object:nil];
        });
    }

该方法没有被调用。如果我让我的各种视图控制器之一成为观察者，那么那个会收到通知，但 AppDelegate 不是。难道就不能让 AppDelegate 成为 NSNotification 观察者吗？

Answer 1

收到通知时调用的方法需要有一个NSNotification 参数。所以，这个方法应该是这样的：

-(void)noConnectionNotification:(NSNotification*)notification {
     NSLog(@"received notification");
    NSString *notificationString = @"Unable to reach server. Changes will be cached.";
    NSDictionary *options = @{kCRToastTextKey : notificationString,
                              kCRToastNotificationTypeKey : @(CRToastTypeStatusBar),
                              kCRToastTextAlignmentKey : @(NSTextAlignmentCenter),
                              kCRToastBackgroundColorKey : [UIColor redColor],
                              kCRToastAnimationInDirectionKey : @(CRToastAnimationDirectionTop),
                              kCRToastAnimationOutDirectionKey : @(CRToastAnimationDirectionTop),
                              kCRToastTimeIntervalKey : @(2),
                              };
    [CRToastManager showNotificationWithOptions:options
                                completionBlock:nil];
}

然后，添加观察者应该如下所示：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(noConnectionNotification:)
                                                 name:@"No_Connection_Available" object:nil];

}

注意@selector 调用中方法名称后面的冒号。