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iOS Build a Self-Destructing Message iPhone App Using Parse.com as a Backend and Adding Users Logging In and Logging Out

Posted by ebadsaghar
ebadsaghar
5,505 Points

block not able to be passed properly

Here's what the instruction say (but I keep getting a compilation error):

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 on line 17. In the login method (where it says "Add your code below!"), add a call to the PFUser class method logInWithUsernameInBackground:password:block:. Use @"test" as the 1st and 2nd parameters. Then pass in loginHandler as the 3rd parameter.

#import "LoginViewController.h"
#import "UIAlertView.h"
#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

3 Answers

Julian Thayn
Julian Thayn
2,592 Points
Julian Thayn
Julian Thayn
2,592 Points

You do not need the () at the end of loginHandler

ebadsaghar
ebadsaghar
5,505 Points

Julian, I do have it at the end.

Troy Fine
Troy Fine
7,592 Points
Troy Fine
Troy Fine
7,592 Points

I have not gotten this far in my iOS development track but this looks like a syntax error.

ebadsaghar
ebadsaghar
5,505 Points

Thank you Troy for responding. I know there is AN error some where, but I can't seem to find the error.

Julian Thayn
Julian Thayn
2,592 Points
Julian Thayn
Julian Thayn
2,592 Points

Right, you DO NOT need it at the end:

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

ebadsaghar
ebadsaghar
5,505 Points

read that wrong, sorry.