title: No visible @interface for 'UIResponder' declares the selector 'viewDidAppear'
body: <p>I am making a login page for an application using Parse.
  I get the error "visible @interface for 'UIResponder' declares the selector 'viewDidAppear'" 
  I also get "visible @interface for 'UIResponder' declares the selector 'presentViewController:animated:present'" </p>
  
  <p>So, in my AppDelegate.m I have:</p>
  
  <pre><code> - (void)viewDidAppear:(BOOL)animated {
      [super viewDidAppear:animated];//I GET THE ERROR HERE
  
      if (![PFUser currentUser]) { // No user logged in
          // Create the log in view controller
          PFLogInViewController *logInViewController = [[PFLogInViewController alloc] init];
          [logInViewController setDelegate:self]; // Set ourselves as the delegate
  
          // Create the sign up view controller
          PFSignUpViewController *signUpViewController = [[PFSignUpViewController alloc] init];
          [signUpViewController setDelegate:self]; // Set ourselves as the delegate
  
         // Assign our sign up controller to be displayed from the login controller
          [logInViewController setSignUpController:signUpViewController];
  
          // Present the log in view controller
          [self presentViewController:logInViewController animated:YES completion:NULL];//I GET THE ERROR HERE
  
          }
      }
  </code></pre>
  
  <p>In my AppDelegate.h:</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  #import &lt;Parse/Parse.h&gt;
  
  @interface AppDelegate : UIResponder &lt;UIApplicationDelegate&gt;
  
  @property (strong, nonatomic) UIWindow *window;
  
  @end
  
  // Implement both delegates
  @interface DefaultSettingsViewController :
      UIViewController &lt;PFLogInViewControllerDelegate, PFSignUpViewControllerDelegate&gt;
  @end
  </code></pre>
  
  <p>How can I go about fixing this issue?</p>