iOS - Parse - PFQuery Not Working

Question

I am creating a custom class ChatRequest, but when I try to query it, it will not return any custom keys.

Here is my code:

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    PFQuery *query = [PFQuery queryWithClassName:@"ChatRequest"];
    [query setValue:[PFUser currentUser].username forKey:@"toUser"];
    NSArray *objects = [query findObjects];
    for (NSUInteger i = 0; i < objects.count; i++) {
        PFObject *object = [objects objectAtIndex:i];
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Chat Request!" message:object.sendingUser + @"wants to chat with you!" delegate:self cancelButtonTitle:@"Decline" otherButtonTitles:@"Accept", nil];
        [alertView show];
    }
}

Can anyone help? I checked that my class was correct and the keys were there, but it still won't work.

Paulw11 · Accepted Answer · 2014-08-02 03:13:33Z

2

You don't use setValue to add a constraint to a query. You use whereKey:equalTo:, so your code should be:

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    PFQuery *query = [PFQuery queryWithClassName:@"ChatRequest"];
    [query whereKey:@"toUser" equalTo:[PFUser currentUser].username ];
    NSArray *objects = [query findObjects];
    for (NSUInteger i = 0; i < objects.count; i++) {
        PFObject *object = [objects objectAtIndex:i];
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Chat Request!" message:object.sendingUser + @"wants to chat with you!" delegate:self cancelButtonTitle:@"Decline" otherButtonTitles:@"Accept", nil];
        [alertView show];
    }
}

However, for performance reasons it is a bad idea to call the find objects synchronously like this. You should use - (void)findObjectsInBackgroundWithBlock:(PFArrayResultBlock)block to allow the query to complete in the background. In the completion block you can refresh your UI.

Also, from a design point of view your toUser should be a reference type column, not a string type. You could then use

[query whereKey:@"toUser" equalTo:[PFUser currentUser]];

answered Aug 2, 2014 at 3:13

Paulw11

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4 Comments

Oliver Ni Over a year ago

it still does not work when I try to access the username property: object[@"sendingUser"].username

Paulw11 Over a year ago

If sendingUser is a reference type column then you need to add [query includeKey:@"sendingUser"] to have the Parse API retrieve the referenced object

Oliver Ni Over a year ago

it gives property 'username' not found on object of type (id)

Paulw11 Over a year ago

You need to cast the object - PFUser *sender=(PFUser *)object[@"sendingUser"]; NSString *senderName=sender.username

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