Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS

Posted by Caleb Abraham
Caleb Abraham
15,158 Points

Logging In and Logging Out Code Challenge

Now switch to LoginViewController.m. Blocks can also be declared and passed around as variables, as we can see in the existing code below. This code declares a block named 'loginHandler'. In the login method (after the block), add a call to the PFUser class method 'logInWithUsernameInBackground:password:block:'. Use "test" as both the username and password parameters. Then pass in 'loginHandler' as the third parameter. You can use block variables in this manner like how you would use any other variable as a parameter. My code is: // Add your code below! [PFUser logInWithUsernameInBackground:test password:test block:loginHandler]; But I can't seem to see what is wrong.

1 Answer

Caleb Abraham
Caleb Abraham
15,158 Points
Caleb Abraham
Caleb Abraham
15,158 Points 
#import <Parse/Parse.h>

@implementation LoginViewController

  • (void)viewDidLoad { [super viewDidLoad]; }

  • (IBAction)login:(id)sender { // This is an example of how to declare a block named loginHandler. It starts with a // return type, then the name of the block with a special syntax for naming. The next // set of parentheses hold the parameters and their types. Then assigning the block // on the right side looks just like how we defined it in the video (carat with the // same parameters in parentheses). void (^loginHandler)(PFUser *user, NSError *error) = ^(PFUser *user, NSError *error) { if (error) { UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Sorry!" message:@"Error logging in." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alertView show]; } else { [self.navigationController popToRootViewControllerAnimated:YES]; } };

    // Add your code below! [PFUser logInWithUsernameInBackground:test password:test block:loginHandler]; }

@end

Tord Asnes
Tord Asnes
7,078 Points

Hi!

You just need to pass the username and password as strings:

[PFUser logInWithUsernameInBackground:@"test" password:@"test" block:loginHandler];