@interface NSString (SearchingAdditions)

- (BOOL) containsString:(NSString *)aString;
- (BOOL) containsString:(NSString *)aString ignoringCase:(BOOL)flag;

@end
@implementation NSString (SearchingAdditions)

- (BOOL)containsString:(NSString *)aString {
    return [self containsString:aString ignoringCase:NO];
}

- (BOOL)containsString:(NSString *)aString ignoringCase:(BOOL)flag {
    unsigned mask = (flag ? NSCaseInsensitiveSearch : 0);
    return [self rangeOfString:aString options:mask].length > 0;
}

@end

NSString Contains String Additions

Objective C