Question

After following the overview found here:

https://developers.google.com/analytics/devguides/collection/ios/v2/

I am seeing an Unused variable "tracker" warning on the last line of the code added to:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

Here’s the code from Google’s overview page:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  // Optional: automatically track uncaught exceptions with Google Analytics.
  [GAI sharedInstance].trackUncaughtExceptions = YES;
  // Optional: set Google Analytics dispatch interval to e.g. 20 seconds.
  [GAI sharedInstance].dispatchInterval = 20;
  // Optional: set debug to YES for extra debugging information.
  [GAI sharedInstance].debug = YES;
  // Create tracker instance.
  id<GAITracker> tracker = [[GAI sharedInstance] trackerWithTrackingId:@"UA-YOUR-TRACKING-ID"];

}

tracker truly sees absolutely no use past this point and the overview document doesn’t really say what to do with it. Any suggestions?

Answer 1

If you don’t need a reference to your tracker (and it looks like you don’t) you can remove the warning by changing the last line of code from

id<GAITracker> tracker = [[GAI sharedInstance] trackerWithTrackingId:@"UA-YOUR-TRACKING-ID"];

to

[[GAI sharedInstance] trackerWithTrackingId:@"UA-YOUR-TRACKING-ID"];

A use case for keeping a reference to the tracker in this block of code could be if you wanted to create an event for when a user starts the application, without having to call [GAI sharedInstance] to get that reference.