+ (NSString*)identifierForVender{
UICKeyChainStore *keyChain = [UICKeyChainStore keyChainStore];
NSString *bundleID = [[NSBundle mainBundle] bundleIdentifier];
bool keyExist = [keyChain contains:bundleID];
NSString *uuidStr = nil;
if (keyExist) {
uuidStr = [keyChain stringForKey:bundleID];
return uuidStr;
}
uuidStr = [[[[UIDevice currentDevice] identifierForVendor] UUIDString] stringByAppendingString:bundleID];
NSLog(@"uuidStr2:%@",uuidStr);
[keyChain setString:uuidStr forKey:bundleID];
return uuidStr;
}