Wayne Filkins Wayne Filkins - 1 month ago 19
Swift Question

How to populate collectionView with posts using Firebase and Swift

I'm trying to fill the collectionView with posts. I have to get the posts, then get some data for the users who posted them. For some reason it isn't working.

DataService.ds.REF_POSTS.child("\(self.loggedInUser!.uid)").queryLimitedToLast(30).observeSingleEventOfType(.Value, withBlock: { postDictionary in
if postDictionary.exists() {
if let snapshots = postDictionary.children.allObjects as? [FIRDataSnapshot] {
self.posts = [Post]()
for snap in snapshots {
if let postDict = snap.value as? NSDictionary {
for(name, value) in postDict {
let interval = postDict.objectForKey("timePosted") as! Double
let formattedDate = NSDate(timeIntervalSince1970: interval)
let timeAgo = self.getDate(formattedDate)
if name as! String == "postedBy" {
DataService.ds.REF_USERS.child(value as! String).observeSingleEventOfType(.Value, withBlock: { (userDictionary) in
let userDict = userDictionary.value as! NSDictionary
let username = userDict.objectForKey("username")!
let profileThumbUrl = userDict.objectForKey("profileThumbUrl")!
let key = snap.key
let post = Post(postKey: key, dictionary: postDict, username: username as! String, profileThumbUrl: profileThumbUrl as! String, timeAgo: timeAgo)
self.posts.append(post)
})
}
}
}
}
}
}
self.collectionView?.reloadData()
})


It works if I perform the reload() right after appending the posts, but there is some sort of memory leak. There isn't a problem in the Post class or filling the collection view, if I use dummy values. The problem is in this code that I posted. I think I have an extra loop or something can anyone help?

Answer

If you fear that reload() is the reason of the memory leak (Which i doubt), but you can use this hack:-

 if name as! String == "postedBy" {
                                DataService.ds.REF_USERS.child(value as! String).observeSingleEventOfType(.Value, withBlock: { (userDictionary) in
                                    let userDict = userDictionary.value as! NSDictionary
                                    let username = userDict.objectForKey("username")!
                                    let profileThumbUrl = userDict.objectForKey("profileThumbUrl")!
                                    let key = snap.key
                                    let post = Post(postKey: key, dictionary: postDict, username: username as! String, profileThumbUrl: profileThumbUrl as! String, timeAgo: timeAgo)
                                    self.posts.append(post)

                                if posts.count == postDictionary.childrenCount{

                                 self.collectionView?.reloadData()

                                    } 
                                })
                            }

Then also see this answer :- Firebase observeSingleEventOfType stays in memory