Why are my feed cells duplicating? - ios

Question

I am using this code to create a feed view that shows users, images, and comments similar to instagram. For some reason, the cells on the feed are duplicating the current user's posts. Not only that, but it is also putting the incorrect username with the images on the duplicate cells. What am I doing wrong?
import UIKit
import Parse
class FeedTableViewController: UITableViewController {
var usersBeingFollowed = [String]()
var imageFiles = [PFFile]()
var imageComment = [""]
var usernames = [String]()
override func viewDidLoad() {
super.viewDidLoad()
navigationItem.hidesBackButton = true
let getFollowedUsersQuery = PFQuery(className: "Followers")
getFollowedUsersQuery.whereKey("follower", equalTo: PFUser.currentUser()!.objectId!)
getFollowedUsersQuery.findObjectsInBackgroundWithBlock { (objects, error) -> Void in
self.usernames.removeAll(keepCapacity: true)
self.imageComment.removeAll(keepCapacity: true)
self.imageFiles.removeAll(keepCapacity: true)
self.usersBeingFollowed.removeAll(keepCapacity: true)
if let objects = objects {
for object in objects {
let followedUser = object["following"] as! String
let getFollowedUsers = PFQuery(className: "Post")
getFollowedUsers.whereKey("userId", equalTo: followedUser)
let getCurrentUser = PFQuery(className: "Post")
getCurrentUser.whereKey("userId", equalTo: (PFUser.currentUser()?.objectId)!)
var query = PFQuery.orQueryWithSubqueries([getFollowedUsers,getCurrentUser])
query.findObjectsInBackgroundWithBlock({ (imageObjects, error) -> Void in
if let objects = imageObjects {
for images in objects {
let userQuery = PFUser.query()
userQuery?.whereKey("_id", equalTo: images["userId"])
userQuery?.findObjectsInBackgroundWithBlock({ (user, error) -> Void in
print(user)
if let user = user {
for username in user {
self.usernames.append(username["username"] as! String)
}
}
})
self.imageFiles.append(images["imageFile"] as! PFFile)
self.imageComment.append(images["imageComment"] as! String)
self.tableView.reloadData()
}
}
})
}
}
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return usernames.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let myCell = tableView.dequeueReusableCellWithIdentifier("imagePostCell", forIndexPath: indexPath) as! cell
if imageFiles.count > 0{
myCell.userLabel.text = "\(usernames[indexPath.row]) completed the \(imageComment[indexPath.row]) challenge!"
imageFiles[indexPath.row].getDataInBackgroundWithBlock({ (data, error) -> Void in
if let downloadedImage = UIImage(data: data!) {
myCell.imagePost.image = downloadedImage
// self.tableView.reloadData()
}
})
}
return myCell
}

Answer 1

You should reset the cell property before add new values, you can use
prepareForReuse()
More info on Apple Doc https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UITableViewCell_Class/index.html#//apple_ref/occ/instm/UITableViewCell/prepareForReuse

Answer 2

It will be obviously, generate the duplicate content because you have put the condition that if imageFiles.count > 0 then the data will be displayed.
But what when there are no images? It will definitely take the value from reusable UITableViewCell. Check the below change:
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let myCell = tableView.dequeueReusableCellWithIdentifier("imagePostCell", forIndexPath: indexPath) as! cell
if imageFiles.count > 0{
myCell.userLabel.text = "\(usernames[indexPath.row]) completed the \(imageComment[indexPath.row]) challenge!"
imageFiles[indexPath.row].getDataInBackgroundWithBlock({ (data, error) -> Void in
if let downloadedImage = UIImage(data: data!) {
myCell.imagePost.image = downloadedImage
// self.tableView.reloadData()
}
})
}else{
myCell.userLabel.text = "Put What You Want Here" //make just nil
myCell.imagePost.image = UIImage(name: "placeholder.png") //Some Placeholder image when there is no data
}
return myCell
}