CODEWITHSUNDEEP
iosobjective-cparse-platformobjective-c-blockspfquery
t.ios
t.ios

Reputation: 1042

my parse query does not complete until after the rest of the app does, how do i stop this from happening?

Below is the parse query, i am trying to display the categories in a collection view, but the numberOfItemsInSection method runs before getCategories has the time to pull information from parse. numberOfItemsInSection uses getCategories _anArrayOfCategories to return the number of categories in the collection view. 

-(void)getCategories{
    [super viewWillAppear:animated];   //calls retrieve messages method below

    //get Categories where the class name is Categories
    PFQuery *query = [PFQuery queryWithClassName:@"Categories"];
    //- (void)selectKeys:(NSArray *)keys
    [query selectKeys:@[@"CName"]];
    //[query whereKey:@"recipientIds" equalTo:[[PFUser currentUser] objectId]];
    [query orderByAscending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (error) {
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }

        else {
            _anArrayOfCategories = [[NSArray alloc] initWithArray:objects];
            NSLog(@"Test 1: Retrieved %lu Categories", (unsigned long)[_anArrayOfCategories count]);

        }
    }];

}

any suggestions?

Upvotes: 0

Views: 65

Answers (1)

Stonz2
Stonz2

Reputation: 6396

Either update your table after the query finishes, or make the query on a previous controller and push to this controller after it completes. Remember that these are UI operations and need to be done on the main thread.

[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (error) {
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }

    else {
        _anArrayOfCategories = [[NSArray alloc] initWithArray:objects];
        NSLog(@"Test 1: Retrieved %lu Categories", (unsigned long)[_anArrayOfCategories count]);
        dispatch_async(dispatch_get_main_queue(), ^{ // UI operations on the main thread
            [self.tableView reloadData];
        });

    }
}];

Edit: Just to make sure, as it's unclear from your post, you don't want to call this method from numberOfRowsInSection. Put it in viewDidLoad or something similar, and then have numberOfRowsInSection use the _anArrayOfCategories object.

Upvotes: 1

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