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I am trying to check if the current user has liked a post uploaded in my application. I am using UICollectionView. The code looks like this:

    var query2 = PFQuery(className: "currentUploads")
            query2.whereKey("objectId", equalTo: post.objID)
            query2.whereKey("likedBy", equalTo: self.thisUser!)
            query2.getFirstObjectInBackgroundWithBlock {
                (object: PFObject?, error: NSError?) -> Void in
                if error != nil || object == nil {
                    println("Like does not exist.")
                    cell.likeButton.setTitleColor(UIColor.blueColor(), forState: .Normal)
                }
                else{
                    println("Like does exist.")
                    cell.likeButton.setTitleColor(UIColor.redColor(), forState: .Normal)
                }
            }

I have been using that code in cellForItemAtIndexPath, and I heard that I should never query in cellForItemAtIndexPath. The "post.objID" is the object id from parse for the current object row. The `"likedBy"` is a array in parse that contains usernames, and "self.thisUser" is the username for the current user.

Like button action:

    @IBAction func likeButtonAction(sender: AnyObject) {
            let buttonPosition = sender.convertPoint(CGPointZero, toView: self.collectionView)
            let indexPath = self.collectionView.indexPathForItemAtPoint(buttonPosition)
            ////
            //println(indexPath?.item)
            ////
            let post = self.arrayOfDetails[indexPath!.item]
            println(post.likedBy)

            let cell = collectionView.cellForItemAtIndexPath(indexPath!) as! CollectionViewCell

            //cell.likeButton.enabled = false

            if (post.likedBy.containsObject(thisUser!)){
                let queryDislike = PFObject(withoutDataWithClassName: "currentUploads", objectId: post.objID)

                queryDislike.removeObject(self.thisUser!, forKey: "likedBy")
                println("STEP 1: Current user removed from likedBy column")

                //Save
                queryDislike.saveInBackgroundWithBlock {
                    (success: Bool, error: NSError?) -> Void in
                    if (success) {
                        // The object has been incremented
                        println("STEP 3: Successfully saved")
                        self.queryFromParse()

                    } else {
                        // There was a problem, check error.description
                        //println(error!.description)
                    }
                }
            }
            else{
                let queryLike = PFObject(withoutDataWithClassName: "currentUploads", objectId: post.objID)

                queryLike.addObject(self.thisUser!, forKey: "likedBy")
                println("STEP 1: Current user added to likedBy column")

                // Save
                queryLike.saveInBackgroundWithBlock {
                    (success: Bool, error: NSError?) -> Void in
                    if (success) {
                        // The object has been incremented
                        println("STEP 3: Successfully saved")
                        self.queryFromParse()

                    } else {
                        // There was a problem, check error.description
                        //println(error!.description)
                    }
                }
            }
        }

And suggestions on how I can do this? If the user already has liked a photo, the button will be red, if the user has not liked the photo, the button will be blue(color is for testing only).