How can I detect my app was launched for background fetch in didFinishLaunchingWithOptions method?

Question

I want to check whether my app was launched for background fetch in my application delegate's didFinishLaunchingWithOptions. There is nothing in launchOptions dictionary. So is there any way to check it?

I know that I can check applicationState, but for some reason sometimes it returns UIApplicationStateBackground, even if I launch app normally.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    if (application.applicationState != UIApplicationStateBackground) {
    // Analytics initialization code
    }
}

I've created breakpoint at Analytics initialization code and sometimes it enters to this block even if I launch app normally!

I know that I can detect the state later when applicationDidBecomeActive or applicationDidEnterBackground will be called. If I will use these approach to detect the state I need to move my Analytics initialization code to some other place. If it remain in application:didFinishLaunchingWithOptions: it will be called every time when my app starts background fetch. So maybe I should just move Analytics initialization code to some other method and don't check applicationState in application:didFinishLaunchingWithOptions:? If so which method I can use for this?

Answer 1

Take a look at slides 19-21 of this presentation: http://www.slideshare.net/moliver816/background-fetch

Immediately upon launch, you can check if applicationState equals UIApplicationStateBackground in order to determine whether your app was launched into the background.

Otherwise, if you just want to know when your app is fetching data for background app refresh, you can do so inside the UIApplicationDelegate method application:performFetchWithCompletionHandler:.

Answer 2

You can wrap you analytics initialization code in a singleton using GCD dispatch once. That way you know it only runs one time per application load. Resume from background or any other states won't matter since the lifecycle is still continuous.

+ (Analytics*)sharedInstance
  {
     static dispatch_once_t onceToken;
     static Analytics* sharedInstance;
     dispatch_once(& onceToken, ^{
         sharedInstance = [[self alloc] init];
         //Do analytics initialization code here
      });
     return sharedInstance;
  }