You have no errors. "Unused" is a warning that means you're not using the "user" variable for anything. Sure, you're giving it a value, but you're not using that value afterwards. A simple call to NSLog displaying something will remove that warning:
NSLog(@"Username: %@", user[@"username"];
Also, as shim stated, the warning about a long-running Parse operation is because you use
[query getFirstObject];
which is run on the main thread. To get rid of that warning, you use one of the background functions, like
[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
if (object) {
PFUser *user = (PFUser *)object;
NSLog(@"Username: %@", user[@"username"]);
}
}];
UPDATE
Edit the function like this (no quotes for searchResult):
- (IBAction)searchButton:(id)sender {
NSString *searchResult = [self.searchField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
PFQuery *query = [PFUser query];
[query whereKey:@"username" equalTo:searchResult];
PFUser *user = (PFUser *)[query getFirstObject];
// NSArray *searchedItem = [query findObjects];
}