Alternative to iPhone device ID (UDID)

You can get iPhone device ID using this "udid" method and you can download OpenUDID class from https://github.com/ylechelle/OpenUDID 

+ (NSString *)udid

{

    NSUserDefaults *standardUserDefault = [NSUserDefaults standardUserDefaults];

   

    static NSString *uuid = nil;

   

    // try to get the NSUserDefault identifier if exist

    if (uuid == nil) {

       

        uuid = [standardUserDefault objectForKey:@"UniversalUniqueIdentifier"];

    }

   

    // if there is not NSUserDefault identifier generate one and store it

    if (uuid == nil) {

       

        uuid = [self genarateUDID];

        [standardUserDefault setObject:uuid forKey:@"UniversalUniqueIdentifier"];

        [standardUserDefault synchronize];

    }

   

    return uuid;

}

+ (NSString *)genarateUDID

{

    NSString *uniqiPhoneID;

   

    if (!NSClassFromString(@"ASIdentifierManager")) {

        // This is will run before iOS6 and you can use openUDID, per example...

        uniqiPhoneID = [OpenUDID value];

    }

    if (uniqiPhoneID == nil || [uniqiPhoneID isEqual:[NSNull null]])

    {

       

        CFUUIDRef uuid = CFUUIDCreate(NULL);

        CFStringRef udidString = CFUUIDCreateString(NULL, uuid);

        CFRelease(uuid);

       

        uniqiPhoneID = (__bridge NSString *)(udidString);

       

    }

   

    return uniqiPhoneID;

}

How to Check Null or Empty in given String

+ (BOOL)isNullOrEmpty:(NSString *)string

{

    if (string == nil)  {

        return YES;

    }

    if ((![string isKindOfClass:[NSNumber class]]) && (![string isKindOfClass:[NSString class]]) && (![string isKindOfClass:[NSDictionary class]]) && (![string isKindOfClass:[NSArray class]])) {

        return YES;

    }

   

    if (([string isKindOfClass:[NSString class]]) && ([string isEqualToString:@""])){

        return YES;

    }

   

    return NO;

}

How to compare date

//-------compare date ------------------------///

    NSDate *today = [NSDate date]; // it will give you current date

    NSDateFormatter *format = [[NSDateFormatter alloc] init];

    [format setDateFormat:@"MM/dd/yyyy"];

    NSDate *todayFormat = [format dateFromString:[format stringFromDate:today]]; // your date

   

    NSComparisonResult result;

    //has three possible values: NSOrderedSame,NSOrderedDescending, NSOrderedAscending

   

    result = [todayFormat compare:historyDate]; // comparing two dates

    NSString *dateString;

   

    if(result==NSOrderedAscending || result==NSOrderedDescending){

        [format setDateFormat:@"EEEE MMM dd yyyy"];

        dateString = [format stringFromDate:historyDate];

    }else{

        dateString  = @"Today";

    }

Get Local time when have GMT time

- (NSDate *)converteLocalTimeWithGMT:(NSDate *)GMTTime

{

    NSDateFormatter *format = [[NSDateFormatter alloc] init];

    [format setDateFormat:@"MM/dd/yyyy"];

   

    NSTimeZone *timeZone = [NSTimeZone localTimeZone];

    NSInteger timeStamp = [GMTTime timeIntervalSince1970];

    NSInteger fullTime = timeStamp + timeZone.secondsFromGMT;

   

    return [format dateFromString:[format stringFromDate:[NSDate dateWithTimeIntervalSince1970:fullTime]]];  // return Local time

}