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

Answering to see if people can find fault in this. It seemed longer than the others I find here, but it does tell you if app is running for the first time since updating (for this you have to change your info.plist)...

// called during startup, compares the current version string with the one stored on standardUserDefaults
+ (BOOL)isFreshInstallOrUpdate
{
    BOOL ret = YES;
    NSString *cfBundleVersionStored = [[NSUserDefaults standardUserDefaults] objectForKey:@"CFBundleVersion"];
    NSString *cfBundleShortVersionStringStored = [[NSUserDefaults standardUserDefaults] objectForKey:@"CFBundleShortVersionString"];

    NSString *cfBundleVersionPlist = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"];;
    NSString *cfBundleShortVersionStringPlist = [[NSBundle mainBundle] objectForInfoDictionaryKey:
                                                 @"CFBundleShortVersionString"];

    ret = [cfBundleVersionPlist compare:cfBundleVersionStored] != NSOrderedSame ||
    [cfBundleShortVersionStringPlist compare:cfBundleShortVersionStringStored] != NSOrderedSame;

    return ret;
}


// calling this once will necessarily cause isFreshInstall to return false
+ (void)setStoredVersionNumber
{
    NSString *cfBundleVersionPlist = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"];
    NSString *cfBundleShortVersionStringPlist = [[NSBundle mainBundle] objectForInfoDictionaryKey:
                                                 @"CFBundleShortVersionString"];

    [[NSUserDefaults standardUserDefaults] setObject:cfBundleVersionPlist forKey:@"CFBundleVersion"];
    [[NSUserDefaults standardUserDefaults] setObject:cfBundleShortVersionStringPlist forKey:@"CFBundleShortVersionString"];

    // setting now as unfresh!
    [[NSUserDefaults standardUserDefaults] synchronize];
}