Insert object on parse in my table

Question

I have a view controller with inside table and I want to fill her with an array saved on Parse. To download the data I use this code:

 PFQuery *query = [PFQuery queryWithClassName:@"myClass"];
[query whereKey:@"X" equalTo:@"Y"];
[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
    if(error==nil){

       myArray=[object objectForKey:@"Z"];
       NSLog(@"%@",myArray);
    }

}];
}

Now I display it inside myarray the data on parse. But if I use arrays to populate the table it is always me empty. I used NSLog and I saw that outside of the method [query getFirstObjectInBackgroundWithBlock: ^ (PFObject * object, NSError * error) my array is always empty. How can help me?

Answer 1

Fetching data from a remote database takes a little time. The parse functions that take block params run asynchronously. See the comments within your slightly modified code...

[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
    if(error==nil){
       // this appears first in the file, but runs later
       // after the request is finished
       myArray=[object objectForKey:@"Z"];
       NSLog(@"%@",myArray);
       // tell our view that data is ready
       [self.tableView reloadData];
    }
}];

// this appears second in the file, but runs right away, right
// when the request is started
// while execution is here, the request isn't done yet
// we would expect myArray to be uninitialized

Be sure, in your datasource methods e.g. numberOfRows to answer myArray.count. And use the data in the array myArray[indexPath.row] when building the table view cell.