how to keep current user session active using parse?

Question

I am attempting to keep the current user session active until the user decides to log out. What code i should i implement? and exactly where should it be implemented? the viewDidLoad, or viewWillAppear function of the root view? I have tried using this code in my root view:

override func viewDidAppear(animated: Bool) {
        let vc = ViewController()
        var loggedIn = false

        if PFUser.currentUser() != nil {
            loggedIn = true
        } else {
            presentViewController(vc, animated: true, completion: nil)
        }
    }

but whenever i stop the simulator and run it again, i have to log in all over again. What is the best solution? keep in my "ViewController" is my main view which holds my login/sign up fields. So i basically want a way to say if a current user session exist, continue, else, show initial view.

Answer 1

Try this in your app delegate...

-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

...

PFUser *currentUser = [PFUser currentUser];

if (currentUser) {
  // there is a user logged in go to the main screen
    UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
    MainViewController *mainViewController = (MainViewController *)[mainStoryboard instantiateViewControllerWithIdentifier:@"Main"];

    //set the root controller to it
    self.window.rootViewController = mainViewController;
} else {
// Log in!
    UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Login" bundle: nil];
    LoginViewController *loginViewController = (LoginViewController *)[mainStoryboard instantiateViewControllerWithIdentifier:@"Login"];

    //set the root controller to it
    self.window.rootViewController = loginViewController;
}

...