错误：没有结果符合查询条件

Question

method in one class:

- (IBAction)createGroup:(id)sender {
    PFObject *message = [PFObject objectWithClassName:@"Messages"];
    [message setObject:self.recipients forKey:@"recipientIds"];
    [message saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (error) {
            NSLog(@"Error %@ %@", error, [error userInfo]);
        }
        else [self performSegueWithIdentifier:@"showDate" sender:self];
    }];
}

then in another:

    else {
            PFQuery *message = [PFQuery queryWithClassName:@"Message"];
                [message getObjectInBackgroundWithId:@"message" block:^(PFObject *message,         NSError *error) {
                [message setObject:file forKey:@"file"];
                [message setObject:fileType forKey:@"fileType"];
                [message setObject:[[PFUser currentUser] objectId] forKey:@"senderId"];
                [message setObject:[[PFUser currentUser] username] forKey:@"senderName"];
                [message saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {

When I run the app, there are no errors or warnings but it terminates throwing the error when the query is accessed. I'm sure it is something simple that I am overlooking as I just popped my programming cherry a week ago. Any help would be greatly appreciated. Cheers!

Answer 1

The getObjectInBackgroundWithId:block: expects a Parse object ID for the objectId parameter.

If you're simply creating the object and then trying to pass it through to a child view controller, it might be better to pass through the actual PFObject .

//In your header
@property (nonatomic, strong) PFObject *message;

 //Implementation
 (IBAction)createGroup:(id)sender {
   PFObject *message = [PFObject objectWithClassName:@"Messages"];
   [message setObject:self.recipients forKey:@"recipientIds"];
   [message saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
       if (error) {
           NSLog(@"Error %@ %@", error, [error userInfo]);
       }
       else {
         self.message = message;
         [self performSegueWithIdentifier:@"showDate" sender:self];
       }
   }];
}

You'll need to implement prepareForSeque:sender: in your view controller, and then pass the PFObject through to the child view controller:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
  if ([segue.identifier isEqualToString:@"showDate"]) {
    YourChildViewController *destViewController = segue.destinationViewController;
    destViewController.message = self.message;
  }
}

Then in your child view controller:

//In the header, create a property to hold the message object
@property (nonatomic, strong) PFObject *message;

//In the body, you can use self.message
  [self.message setObject:file forKey:@"file"];
  [self.message setObject:fileType forKey:@"fileType"];
  [self.message saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
  ...