How do i make a Parse query for a username that was added to a UITextField?

Question

I have a UITextfield called searchField, a UIButton called searchButton and a Table View. I want to query for the username that was written into the UITextField and display the result in the table view.
It would be amazing, if somebody could help me to figure out the right way. I tried to do this way without any success:
'''objective-c
- (void)viewDidLoad
    {
    [super viewDidLoad];
mainArray = [[NSArray alloc] initWithObjects:@"User", nil];

}

-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [mainArray count];
}

-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"thisCell"];
cell.textLabel.text = [mainArray objectAtIndex:indexPath.row];
return cell;
}

- (IBAction)searchButton:(id)sender {
  NSString *searchResult = [self.searchField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

PFQuery *query = [PFUser query];
    [query whereKey:@"username" equalTo:@"searchResult"];
    [query includeKey:@"username"];
    [query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
        if (object) {
            PFUser *user = (PFUser *)object;
            NSLog(@"Username: %@", user[@"username"]);
        }
    }];'''

Dávid Szép · Accepted Answer

Örülök, hogy segíthettem. :) 
A továbbiak in English:
You just need replace the type of mainArray in the header to NSMutableArray and the initialization in the viewDidLoad to 
objective-c
mainArray = [[NSMutableArray alloc] initWithObjects:@"User", nil];

Here is the useful link for difference between NSArray and NSMutableArray:
http://stackoverflow.com/questions/1345215/difference-between-nsarray-and-nsmutablearray

Dávid Szép · Answer

You can use PFQueryTableViewController instead of UITableViewController, here you find the documentation: https://parse.com/docs/iosguide#ui-tables/iOS
(use the @"User" for parseClassName property)
But if you still use UITableViewController, this code is working for me:
([query includeKey:] method is just used, when you need fetch related objects,  documentation: https://www.parse.com/docs/ios_guide#objects-pointers/iOS 
or 
http://blog.parse.com/2011/12/06/queries-for-relational-data/)
```objective-c
- (IBAction)searchButton:(id)sender {
  NSString *searchResult = [self.searchField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
  PFQuery *query = [PFUser query];
  [query whereKey:@"username" equalTo:searchResult];
  [query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
  if (object) {
            PFUser *user = (PFUser *)object;
            NSLog(@"Username: %@", user.username);
            if (mainArray.count > 0) {
                 [mainArray replaceObjectAtIndex:0 withObject:user.username];
            } else {
                 [mainArray addObject:user.username];
            }
            [self.tableView reloadData];
        }
    }];
}
```
I hope that I helped.

Dávid Szép · Answer

or if you want to use the NSArray, you just reinitialize the array with the username.
```objective-c
- (IBAction)searchButton:(id)sender {
  NSString *searchResult = [self.searchField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
  PFQuery *query = [PFUser query];
  [query whereKey:@"username" equalTo:searchResult];
  [query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
  if (object) {
            PFUser *user = (PFUser *)object;
            NSLog(@"Username: %@", user.username);
            mainArray = [[NSArray alloc] initWithObjects:user.username, nil];
            [self.tableView reloadData];
        }
    }];
}
```

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Szabolcs Varga

Szabolcs Varga

How do i make a Parse query for a username that was added to a UITextField?

3 Answers

Dávid Szép

Dávid Szép

Szabolcs Varga

Szabolcs Varga

Dávid Szép

Dávid Szép

Szabolcs Varga

Szabolcs Varga

Dávid Szép

Dávid Szép

Dávid Szép

Dávid Szép