How to determine the date an app is installed or used for the first time?

Question

I\'m planning on opening up an in app store and I\'d like to give existing users some of the items for free.

I thought of releasing an update which would store some

Answer 1

To get the installation date, check the creation date of the Documents folder.

NSURL* urlToDocumentsFolder = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
__autoreleasing NSError *error;
NSDate *installDate = [[[NSFileManager defaultManager] attributesOfItemAtPath:urlToDocumentsFolder.path error:&error] objectForKey:NSFileCreationDate];

NSLog(@"This app was installed by the user on %@", installDate);

To get the date of the last App update, check the modification date of the App bundle itself

NSString* pathToInfoPlist = [[NSBundle mainBundle] pathForResource:@"Info" ofType:@"plist"];
NSString* pathToAppBundle = [pathToInfoPlist stringByDeletingLastPathComponent];
NSDate *updateDate  = [[[NSFileManager defaultManager] attributesOfItemAtPath:pathToAppBundle error:&error] objectForKey:NSFileModificationDate];

NSLog(@"This app was updated by the user on %@", updateDate);