If notifications are received in the same period of time with a delay of several milliseconds on the device, it will notify you of several alerts with your sound, and even you can see the pop-up window of all these alerts one by one and disappear but the one received last or last , will be displayed only for viewing the application or closing.
If the application is launched or launched by clicking the view button in the notification mode, in order to get information about the notifications viewed, you need to process it in the device itself. The default OS simply ignores all these warnings when the application starts. You should check if a warning is received at application startup.
This can be achieved using the UIApplication delegation method:
(void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
it needs to be implemented. It receives a notification when the application is launched.
After you implement the above method, you will receive a pop-up warning about each notification, even if the application is running. And in this case, it does not start a new instance of the application. It will just show you a pop-up warning. Even if you click on the view, it’s useless. If you want a task to be performed after clicking on the view when the application is running, you can make this new functionality and say that the OS will behave as needed.