how to fix -[__NSCFString gtm_stringByUnescapingFromURLArgument] in google+ authentication - iphone

Question

I am trying to create an application that retrieves the current user's email id, user id, user name from his google+ account. The part of the code is as follows,
- (IBAction)googleSigninBtnTapped:(id)sender
{
[GPPSignInButton class];
[GPPSignIn sharedInstance].clientID =[NSString stringWithFormat:#"MY APP ID"];
GPPSignIn *signIn = [GPPSignIn sharedInstance];
signIn.delegate = self;
signIn.shouldFetchGoogleUserEmail = YES;
signIn.shouldFetchGoogleUserID = YES;
signIn.actions = [NSArray arrayWithObjects:
#"http://schemas.google.com/AddActivity",
#"http://schemas.google.com/BuyActivity",
#"http://schemas.google.com/CheckInActivity",
#"http://schemas.google.com/CommentActivity",
#"http://schemas.google.com/CreateActivity",
#"http://schemas.google.com/ListenActivity",
#"http://schemas.google.com/ReserveActivity",
#"http://schemas.google.com/ReviewActivity",
nil];
[signIn trySilentAuthentication];
}
(void)finishedWithAuth:(GTMOAuth2Authentication *)auth error:(NSError )error
{
if (error)
{
NSLog(#"Status: Authentication error: %#", error);
}
else
{
NSLog(#"Status: Authenticated");
NSLog(#"Email: %#",[GPPSignIn sharedInstance].authentication.userEmail);
GTLServicePlus plusService = [[[GTLServicePlus alloc] init] autorelease];
plusService.retryEnabled = YES;
[plusService setAuthorizer:[GPPSignIn sharedInstance].authentication];
GTLQueryPlus *query = [GTLQueryPlus queryForPeopleGetWithUserId:#"me"];
[plusService executeQuery:query completionHandler:^(GTLServiceTicket *ticket, GTLPlusPerson *person, NSError *error)
{
if (error)
{
GTMLoggerError(#"Error: %#", error);
}
else
{
[person retain];
NSLog(#"%#", person.displayName);
NSLog(#"%#", person.identifier);
}
}];
}
}
But when i am trying to execute my app, it gets crashed, saying that
'-[__NSCFString gtm_stringByUnescapingFromURLArgument]: unrecognized selector sent to instance 0x9e435b0'
Can anybody help me on this...!!!
Thanks In Advance!!!

Answer 1

Yep, you need the -ObjC linker flag in, it's not finding one of the categories from the GoogleOpenSource framework.
See Step 3 in the setup guide: https://developers.google.com/+/mobile/ios/getting-started#step_3_initialize_the_google_client
Basically, in Other Linker Flags, add -ObjC (capitalisation is important, note!). Also make sure you have included both GooglePlus and GoogleOpenSource frameworks in your project.

Answer 2

Add with _objc the other flag called -lc++