ios - postNotificationName 尚未在 appdelegate 类中触发

Question

在 Appdelegate.m 中添加了 postNotification 方法

   - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {

         if(application.applicationState == UIApplicationStateBackground) {

[[NSNotificationCenter defaultCenter] postNotificationName: @"SuggetionPushNotification" object:nil userInfo:userInfo];


              AppDelegate *appDel = (AppDelegate *)[[UIApplication sharedApplication] delegate];

                        SideMenuViewController *leftMenuViewController = [[SideMenuViewController alloc] init];
                        MFSideMenuContainerViewController *container = [MFSideMenuContainerViewController
                                                                        containerWithCenterViewController:[[UINavigationController alloc]
                                                                                                           initWithRootViewController:[[SuggetionViewController alloc] init]]
                                                                        leftMenuViewController:leftMenuViewController
                                                                        rightMenuViewController:Nil];

                         [self.window makeKeyAndVisible];
                        appDel.window.rootViewController = container;

                 }


                    }

ViewController B (SuggetionViewController) 在 vi​​ewDidLoad

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



- (void) receiveTestNotification:(NSNotification *) notification {
    NSLog(@"working");

}

但是这里还没有触发通知，如果在同一个类中添加了 post 和 addobserver，那么只有它会触发。我做错了什么。我从 Send and receive messages through NSNotificationCenter in Objective-C? 转介请帮忙

Answer 1

当您发布通知时，您的 View Controller B 不在内存中，这就是 Controller B 无法观察通知的原因。在发布通知之前添加延迟会有所帮助。

double delayInSeconds = 2.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
  [[NSNotificationCenter defaultCenter] postNotificationName: @"SuggetionPushNotification" object:nil userInfo:nil];

});