Add UINavigationItem to UINavigationController that wraps Google Drive OAuth - objective-c

Question

Goal: For connection to iOS Google Drive, wrap the iOS Google OAuth view controller in a programmatically created navigation controller, and add a Cancel button to enable the user to cancel the Google OAuth process, should they choose to do so.
Problem: While I can successfully wrap the OAuth view controller in a navigation controller, I cannot seem to add a navigation item, such as the desired Cancel button.
I add a navigation controller that wraps the Google Drive OAuth view controller, as follows...
GTMOAuth2ViewControllerTouch *authViewController = nil;
if (!self.isAuthorized) {
SEL selectorFinish = #selector(viewController:finishedWithAuth:error:);
SEL selectorButtonCancel = #selector(buttonCancelTapped:);
authViewController = [[GTMOAuth2ViewControllerTouch alloc] initWithScope:kGTLAuthScopeDrive
clientID:kClientID
clientSecret:kClientSecret
keychainItemName:kKeychainItemName
delegate:self
finishedSelector:selectorFinish];
UINavigationController *navController = [[UINavigationController alloc] init];
[navController addChildViewController:authViewController];
[self.parentTVC presentViewController:navController animated:YES completion:nil];
}
For clarity, the variable parentTVC is a public property,
#property (nonatomic, strong) UITableViewController *parentTVC;
and is set using a custom init method, as follows...
- (id)initWithParentTVC:(UITableViewController *)tvc {
self = [super init];
[self setParentTVC:tvc];
return self;
}
I have attempted to add UINavigationItems to the UINavigationController instance navController, however this does not work, and instead I seem to be stuck with the UIView with the two small buttons (< and >) in the nib file GTMOAuth2ViewTouch.xib, image included below...
I have read through the GTL file GTMOAuth2ViewControllerTouch.m to attempt to see whether there is a method I could possible use or whether I can override by subclassing, but I am not confident in my attempts to do this.
My best guess is that any navigation controller wrapping the OAuth view controller set by this code from GTMOAuth2ViewControllerTouch.m...
- (void)setUpNavigation {
rightBarButtonItem_.customView = navButtonsView_;
self.navigationItem.rightBarButtonItem = rightBarButtonItem_;
}
Assistance please?

Answer 1

This is my re-interpretation of Imran Khan's excellent answer provided in his response to this stack overflow question: Google Drive iOS SDK: Display Cancel Login Button
The googleAuthCheck method should be called in either the viewDidLoad or viewWillAppear method of the parent view controller. (I assume here a reasonable understanding of iOS Google Drive SDK, so let me know if I need to add further clarification.)
Also, albeit a small issue, using initWithBarButtonSystemItem:UIBarButtonSystemItemCancel requires that only the title text of the view controller then needs to be localised (if you are implementing localisation).
- (void)googleAuthCheck {
if (!self.isAuthorized) {
SEL selectorFinish = #selector(viewController:finishedWithAuth:error:);
SEL selectorButtonCancel = #selector(buttonCancelTapped:);
UINavigationController *navController = [[UINavigationController alloc] init];
UINavigationItem *navigationItem = [[UINavigationItem alloc] initWithTitle:<<localised string for title>>];
UIBarButtonItem *barButtonItemCancel = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:selectorButtonCancel];
UINavigationBar *navigationBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 63)];
[navigationItem setRightBarButtonItem:barButtonItemCancel];
[navigationBar setTranslucent:NO];
[navigationBar setItems:[NSArray arrayWithObjects: navigationItem,nil]];
[navController.view addSubview:navigationBar];
GTMOAuth2ViewControllerTouch *authViewController = nil;
authViewController = [[GTMOAuth2ViewControllerTouch alloc] initWithScope:kGTLAuthScopeDrive
clientID:kClientID
clientSecret:kClientSecret
keychainItemName:kKeychainItemName
delegate:self
finishedSelector:selectorFinish];
[navController addChildViewController:authViewController];
[self.parentTVC presentViewController:navController animated:YES completion:nil];
}
}
For clarity, the buttonCancelTapped: method is as follows...
- (IBAction)buttonCancelTapped:(UIBarButtonItem *)sender {
[self.parentTVC dismissViewControllerAnimated:YES completion:^(void){}];
}
For clarity, the variable parentTVC is a public property,
#property (nonatomic, strong) UITableViewController *parentTVC;
and is set using a custom init method, as follows...
- (id)initWithParentTVC:(UITableViewController *)tvc {
self = [super init];
[self setParentTVC:tvc];
return self;
}
This custom init method is called from the parent view controller.