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iOS Build a Self-Destructing Message iPhone App Retrieving and Viewing Data from Parse.com Retrieving Data from Parse.com

Value of type 'NSUInteger' should not be used as format arguments.

I have 2 problems. First, when I write

NSLog(@"Retrieved %d messages", [self.messages count]);

A warning appears: "Value of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead".

The second problem is that my app crashes, this is my code:

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    PFQuery *query = [PFQuery queryWithClassName:@"Messages"];

    [query whereKey:@"recipientIds" equalTo:[[PFUser currentUser] objectId]];
    [query orderByDescending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error){
        if (error) {
            NSLog(@"No mames hay un Error: %@ %@", error, [error userInfo]);
        } else {
            self.messages = objects;
            [self.tableView reloadData];
            NSLog(@"Retrieved %d messages",[self.messages count]);
        }
    }];
}

These are the errors: https://www.dropbox.com/s/uxh5oyf0d0uc8jp/Ribbit.tiff?dl=0 https://www.dropbox.com/s/npmin6291facxek/Ribbit2.tiff?dl=0

And this is my class Messages: https://www.dropbox.com/s/oc0jbdap3ey4mq1/Parse.tiff?dl=0

Please I need help. I don't know what I'm doing wrong.

I found the solution, for the first problem Xcode suggested this:

NSLog(@"Retrieved %lu messages",(unsigned long)[self.messages count]);

For the second problem I was reading the documentation and changed my code to this:

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%@ IN recipientIds", [[PFUser currentUser] objectId]];
    PFQuery *query = [PFQuery queryWithClassName:@"Messages" predicate:predicate];

    [query orderByDescending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error){
        if (error) {
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        } else {
            self.messages = objects;
            [self.tableView reloadData];
            NSLog(@"Retrieved %lu messages",(unsigned long)[self.messages count]);
        }
    }];
}

But... Why does the Ben's code work? I need an explanation. My English isn't that good, so I'm going to write in Spanish. En la documentación aparecen dos ejemplos de como buscar un elemento en un array:

// Find objects where the array in arrayKey contains 2.
// Using PFQuery
[query whereKey:@"arrayKey" equalTo:@2];

// Or using NSPredicate
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"2 IN arrayKey"];
PFQuery *query = [PFQuery queryWithClassName:@"MyClass" predicate:predicate];

¿Por qué el primero le funciona a Ben pero a mi no, hace que la app tenga todos los errores que he mostrado anteriormente? ¿Por qué el segundo si me funciona si son dos formas distintas de hacer lo mismo?

1 Answer

Eduardo, here is a full template for the social network application: Click Here.