I have a table view where depending on the cell class it will download an image from Firebase. I've noticed when using the app that cells with the same cell identifier will show the previous downloaded image before showing the new one. This is what I have before changing it.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if tableData[indexPath.row]["Image"] != nil {
let cell = tableView.dequeueReusableCell(withIdentifier: "imageNotesData", for: indexPath) as! ImageNotesCell
cell.notes.delegate = self
cell.notes.tag = indexPath.row
cell.notes.text = tableData[indexPath.row]["Notes"] as! String
guard let imageFirebasePath = tableData[indexPath.row]["Image"] else {
return cell }
let pathReference = Storage.storage().reference(withPath: imageFirebasePath as! String)
pathReference.getData(maxSize: 1 * 1614 * 1614) { data, error in
if let error = error {
print(error)
} else {
let image = UIImage(data: data!)
cell.storedImage.image = image
}
}
return cell
}
else {
let cell = tableView.dequeueReusableCell(withIdentifier: "notesData", for: indexPath) as! NotesCell
//let noteString = tableData[indexPath.row]["Notes"] as! String
cell.notes.text = tableData[indexPath.row]["Notes"] as! String
cell.notes.delegate = self
cell.notes.tag = indexPath.row
return cell
}
}
Knowing that this is not a good user experience and that it looks clunky, I tried to move the pathReference.getData to where I setup the data but the view appears before my images finish downloading. I have tried to use a completion handler but I'm still having issues.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
getSectionData(userID: userID, city: selectedCity, completion: {(sectionString) in
self.setupTableCellView(userID: userID, city: selectedCity, section: sectionString) { (tableData) in
DispatchQueue.main.async(execute: {
self.cityName?.text = selectedCity
self.changeSections.setTitle(sectionString, for: .normal)
self.currentSectionString = sectionString
self.setupTableData(tableDataHolder: tableData)
})
}
})
}
func setupTableCellView(userID: String, city: String, section: String, completion: #escaping ([[String:Any]]) -> () ) {
let databaseRef = Database.database().reference().child("Users").child(userID).child("Cities").child(city).child(section)
var indexData = [String:Any]()
var indexDataArray = [[String:Any]]()
databaseRef.observeSingleEvent(of: .value, with: { (snapshot) in
for dataSet in snapshot.children {
let snap = dataSet as! DataSnapshot
//let k = snap.key
let v = snap.value
indexData = [:]
for (key, value) in v as! [String: Any] {
//indexData[key] = value
if key == "Image" {
//let pathReference = Storage.storage().reference(withPath: value as! String)
print("before getImageData call")
self.getImageData(pathRef: value as! String, completion: {(someData) in
print("before assigning indexData[key]")
indexData[key] = someData
print("after assigning indexData[key]")
})
} else {
indexData[key] = value
}
}
indexDataArray.append(indexData)
}
completion(indexDataArray)
})
}
func getImageData(pathRef: String, completion: #escaping(UIImage) -> ()) {
let pathReference = Storage.storage().reference(withPath: pathRef as! String)
pathReference.getData(maxSize: 1 * 1614 * 1614, completion: { (data, error) in
if let error = error {
print(error)
} else {
let image = UIImage(data:data!)
print("called before completion handler w/ image")
completion(image!)
}
})
}
I don't know if I am approaching this the right way but I think I am. I'm also guessing that the getData call is async and that is why it will always download after showing the table view.
You can't do this.
Make the request from Firebase.
Over time, you will get many replies - all the information and all the changing information.
When each new item arrives - and don't forget it may be either an addition or deletion - alter your table so that it displays all the current items.
That's OCC!
OCC is "occasionally connected computing". A similar phrase is "offline first computing". So, whenever you use any major service you use every day like Facebook, Snapchat, etc that is "OCC": everything stays in sync properly whether you do or don't have bandwidth. You know? The current major paradigm of device-cloud computing.
Edit - See Fattie's comments about prepareForReuse()!
With reusable table cells, the cells will at first have the appearance they do by default / on the xib. Once they're "used", they have whatever data they were set to. This can result in some wonky behavior. I discovered an issue where in my "default" case from my data, I didn't do anything ecause it already matched the xib, but if the data's attributes were different, I updated the appearance. The result was that scrolling up and down really fast, some things that should have had the default appearance had the changed appearance.
One basic solution to just not show the previous image would be to show a place holder / empty image, then call your asynchronous fetch of the image. Not exactly what you want because the cell will still show up empty...
Make sure you have a local store for the images, otherwise you're going to be making a server request for images you already have as you scroll up and down!
I'd recommend in your viewDidLoad, call a method to fetch all of your images at once, then, once you have them all, in your success handler, call self.tableview.reloadData() to display it all.
Related
I am trying to use Firestore pagination with swift TableView. I used the outline of the code provided by Google in their Firestore docs. Here is my code which loads the first 4 posts from Firestore.
func loadMessages(){
let postDocs = db
.collectionGroup("userPosts")
.order(by: "postTime", descending: false)
.limit(to: 4)
postDocs.addSnapshotListener { [weak self](querySnapshot, error) in
self?.q.async{
self!.posts = []
guard let snapshot = querySnapshot else {
if let error = error {
print(error)
}
return
}
guard let lastSnapshot = snapshot.documents.last else {
// The collection is empty.
return
}
//where do I use this to load the next 4 posts?
let nextDocs = Firestore.firestore()
.collectionGroup("userPosts")
.order(by: "postTime", descending: false)
.start(afterDocument: lastSnapshot)
if let postsTemp = self?.createPost(snapshot){
DispatchQueue.main.async {
self!.posts = postsTemp
self!.tableView.reloadData()
}
}
}
}
}
func createPost(_ snapshot: QuerySnapshot) ->[Post]{
var postsTemp = [Post]()
for doc in snapshot.documents{
if let firstImage = doc.get(K.FStore.firstImageField) as? String,
let firstTitle = doc.get(K.FStore.firstTitleField) as? String,
let secondImage = doc.get(K.FStore.secondImageField) as? String,
let secondTitle = doc.get(K.FStore.secondTitleField) as? String,
let userName = doc.get(K.FStore.poster) as? String,
let uID = doc.get(K.FStore.userID) as? String,
let postDate = doc.get("postTime") as? String,
let votesForLeft = doc.get("votesForLeft") as? Int,
let votesForRight = doc.get("votesForRight") as? Int,
let endDate = doc.get("endDate") as? Int{
let post = Post(firstImageUrl: firstImage,
secondImageUrl: secondImage,
firstTitle: firstTitle,
secondTitle: secondTitle,
poster: userName,
uid: uID,
postDate: postDate,
votesForLeft: votesForLeft,
votesForRight:votesForRight,
endDate: endDate)
postsTemp.insert(post, at: 0)
}else{
}
}
return postsTemp
}
Here is my delegate which also detects the end of the TableView:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let post = posts[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: K.cellIdentifier, for: indexPath) as! PostCell
cell.delegate = self
let seconds = post.endDate
let date = NSDate(timeIntervalSince1970: Double(seconds))
let formatter = DateFormatter()
formatter.dateFormat = "M/d h:mm"
if(seconds <= Int(Date().timeIntervalSince1970)){
cell.timerLabel?.text = "Voting Done!"
}else{
cell.timerLabel?.text = formatter.string(from: date as Date)
}
let firstReference = storageRef.child(post.firstImageUrl)
let secondReference = storageRef.child(post.secondImageUrl)
cell.firstTitle.setTitle(post.firstTitle, for: .normal)
cell.secondTitle.setTitle(post.secondTitle, for: .normal)
cell.firstImageView.sd_setImage(with: firstReference)
cell.secondImageView.sd_setImage(with: secondReference)
cell.userName.setTitle(post.poster, for: .normal)
cell.firstImageView.layer.cornerRadius = 8.0
cell.secondImageView.layer.cornerRadius = 8.0
if(indexPath.row + 1 == posts.count){
print("Reached the end")
}
return cell
}
Previously I had an addSnapshotListener without a limit on the Query and just pulled down all posts as they came. However I would like to limit how many posts are being pulled down at a time. I do not know where I should be loading the data into my model. Previously it was being loaded at the end of the addSnapshotListener and I could still do that, but when do I use the next Query? Thank you for any help and please let me know if I can expand on my question any more.
I’m assuming that your method of detecting when user reaches the bottom of the tableView items is correct.
In my personal opinion setting real-time listeners for pagination would be quite a challenge. I recommend you using a bunch of get calls to do this.
If done in that way, what you need is a function that every time it’s called, it brings the next set of posts. For example, first time it’s called, it’ll fetch 4 latest docs A.K.A posts. Second time it’s called, it’ll fetch the next latest set of posts (4). To clarify the resulting posts from first call is newer than second call. Hopefully this is making sense.
How to?
Maintain two properties, one that keeps track of last document fetched, And one that stores all the posts fetched up to now(array or any applicable data structures). If the function gets called 4 times the array I’m talking about here would have 16posts (provided that there are >= 16 posts in firestore).
Now since we have the point to which we fetched the posts from firestore now, we can use the Firestore API to configure the query to fetch the next set, first call onwards. Each time a set of documents/posts is received it’s appended to the array.
Oh almost forgot, the function I’m speaking of here, has to be called every time the User reaches tableView end.
This solution may or may not be ideal for you, but hopefully it at-least leads you down some path to finding a solution. Any questions are welcome, happy to help..
//I have this solution working in a project, the approach is to detect when the user scrolls and the offset is getting close to the top
//When this happens, you get the next bunch of elements from firestore, insert them in your data source and finallly reload the tableview keeping the scroll offset.
//below are the related methods, hope it helps.
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
if scrollView.contentOffset.y < 300{
self.stoppedScrolling()
}
}
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
if !decelerate {
if scrollView.contentOffset.y < 300{
self.stoppedScrolling()
}
}
}
//When the tableview stops scrolling you call your method getNextPosts which should be very similar to your loadMessages, maybe you dont need a listener, you just need the next posts.
func stoppedScrolling() {
getNextPosts { posts in
self.insertNextPosts(posts)
}
}
//Insert the new messages that you just got
private func insertNextPosts(_ posts: [Post]){
self.messages.insert(contentsOf: posts, at: 0)
self.messagesCollectionView.reloadDataAndKeepOffset()
}
//This function es from MessageKit: https://messagekit.github.io, take it only as reference, besides is for a collectionview but you can adapt it to tableview
public func reloadDataAndKeepOffset() {
// stop scrolling
setContentOffset(contentOffset, animated: false)
// calculate the offset and reloadData
let beforeContentSize = contentSize
reloadData()
layoutIfNeeded()
let afterContentSize = contentSize
// reset the contentOffset after data is updated
let newOffset = CGPoint(
x: contentOffset.x + (afterContentSize.width - beforeContentSize.width),
y: contentOffset.y + (afterContentSize.height - beforeContentSize.height))
setContentOffset(newOffset, animated: false)
}
I am using Firebase to populate a TableView in my iOS app. The first few objects are loaded but once I get to the third item in my list the app crashes with the exception:
'NSRangeException', reason: '*** __boundsFail: index 3 beyond bounds [0 .. 2]'
I know that this means that I am referring to an array at an index that it does not contain however I do not know why.
I create the TableView with a TableViewController and initialize it like so:
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print(posts.count)
return posts.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let post = posts[indexPath.row]
print(post)
let cell = tableView.dequeueReusableCell(withIdentifier: K.cellIdentifier, for: indexPath) as! PostCell
let firstReference = storageRef.child(post.firstImageUrl)
let secondReference = storageRef.child(post.secondImageUrl)
cell.firstTitle.setTitle(post.firstTitle, for: .normal)
cell.secondTitle.setTitle(post.secondTitle, for: .normal)
cell.firstImageView.sd_setImage(with: firstReference)
cell.secondImageView.sd_setImage(with: secondReference)
// Configure the cell...
return cell
}
I believe that the first function creates an array with the number of objects in posts and that the second function assigns values to the template for the cell. The print statement in the first method prints 4 which is the correct number of objects retrieved from firebase. I assume that means an array is created with 4 objects to be displayed in the TableView. This is what is really confusing because the error states that there are only 3 objects in the array. Am I misunderstanding how the TableView is instantiated?
Here is the code that fills the TableView:
func loadMessages(){
db.collectionGroup("userPosts")
.addSnapshotListener { (querySnapshot, error) in
self.posts = []
if let e = error{
print("An error occured trying to get documents. \(e)")
}else{
if let snapshotDocuments = querySnapshot?.documents{
for doc in snapshotDocuments{
let data = doc.data()
if let firstImage = data[K.FStore.firstImageField] as? String,
let firstTitle = data[K.FStore.firstTitleField] as? String,
let secondImage = data[K.FStore.secondImageField] as? String,
let secondTitle = data[K.FStore.secondTitleField] as? String{
let post = Post(firstImageUrl: firstImage, secondImageUrl: secondImage, firstTitle: firstTitle, secondTitle: secondTitle)
self.posts.insert(post, at: 0)
print("Posts: ")
print(self.posts.capacity)
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}
}
}
}
The app builds and runs and displays the first few items but crashes once I scroll to the bottom of the list. Any help is greatly appreciated.
Edit:
override func viewDidLoad() {
super.viewDidLoad()
tableView.dataSource = self
tableView.register(UINib(nibName: K.cellNibName, bundle: nil), forCellReuseIdentifier: K.cellIdentifier)
loadMessages()
}
You're getting an out-of-bounds error because you're dangerously populating the datasource. You have to remember that a table view is constantly adding and removing cells as it scrolls which makes updating its datasource a sensitive task. You reload the table on each document iteration and insert a new element in the datasource at index 0. Any scrolling during an update will throw an out-of-bounds error.
Therefore, populate a temporary datasource and hand that off to the actual datasource when it's ready (and then immediately reload the table, leaving no space in between an altered datasource and an active scroll fetching from that datasource).
private var posts = [Post]()
private let q = DispatchQueue(label: "userPosts") // serial queue
private func loadMessages() {
db.collectionGroup("userPosts").addSnapshotListener { [weak self] (snapshot, error) in
self?.q.async { // go into the background (and in serial)
guard let snapshot = snapshot else {
if let error = error {
print(error)
}
return
}
var postsTemp = [Post]() // setup temp collection
for doc in snapshot.documents {
if let firstImage = doc.get(K.FStore.firstImageField) as? String,
let firstTitle = doc.get(K.FStore.firstTitleField) as? String,
let secondImage = doc.get(K.FStore.secondImageField) as? String,
let secondTitle = doc.get(K.FStore.secondTitleField) as? String {
let post = Post(firstImageUrl: firstImage, secondImageUrl: secondImage, firstTitle: firstTitle, secondTitle: secondTitle)
postsTemp.insert(post, at: 0) // populate temp
}
}
DispatchQueue.main.async { // hop back onto the main queue
self?.posts = postsTemp // hand temp off (replace or append)
self?.tableView.reloadData() // reload
}
}
}
}
Beyond this, I would handle this in the background (Firestore returns on the main queue) and only reload the table if the datasource was modified.
After some fiddling around and implementing #bsod's response I was able to get my project running. The solution was in Main.Storyboard under the Attributes inspector I had to set the content to Dynamic Prototypes.
I'm trying to fetch data from firebase and pass to tableview.
// Model
import UIKit
import Firebase
struct ProfInfo {
var key: String
var url: String
var name: String
init(snapshot:DataSnapshot) {
key = snapshot.key
url = (snapshot.value as! NSDictionary)["profileUrl"] as? String ?? ""
name = (snapshot.value as! NSDictionary)["tweetName"] as? String ?? ""
}
}
// fetch
var profInfo = [ProfInfo]()
func fetchUid(){
guard let uid = Auth.auth().currentUser?.uid else{ return }
ref.child("following").child(uid).observe(.value, with: { (snapshot) in
guard let snap = snapshot.value as? [String:Any] else { return }
snap.forEach({ (key,_) in
self.fetchProf(key: key)
})
}, withCancel: nil)
}
func fetchProf(key: String){
var outcome = [ProfInfo]()
ref.child("Profiles").child(key).observe(.value, with: { (snapshot) in
let info = ProfInfo(snapshot: snapshot)
outcome.append(info)
self.profInfo = outcome
self.tableView.reloadData()
}, withCancel: nil)
}
//tableview
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return profInfo.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "followCell", for: indexPath) as! FollowingTableViewCell
cell.configCell(profInfo: profInfo[indexPath.row])
return cell
}
However it returns one row but profInfo actually has two rows. when I implement print(self.profInfo) inside fetchProf it returns two values. But after passed to tableview, it became one. I'm not sure but I guess the reason is that I put reloadData() in the wrong place because I hit break point and reloadData() called twice. So, I think profInfo replaced by new value. I called in different places but didn't work. Am I correct? If so, where should I call reloadData()? If I'm wrong, how can I fix this? Thank you in advance!
You need to append the new data to the profinfo array. Simply replace the fetchProf method with this:-
func fetchProf(key: String){
var outcome = [ProfInfo]()
ref.child("Profiles").child(key).observe(.value, with: { (snapshot) in
let info = ProfInfo(snapshot: snapshot)
outcome.append(info)
self.profInfo.append(contentOf: outcome)
Dispatch.main.async{
self.tableView.reloadData()
}
} , withCancel: nil)
}
self.tableView.reloadData() must be called from the main queue. Try
DispatchQueue.main.async {
self.tableView.reloadData()
}
if you notice one thing in the following function you will see
func fetchProf(key: String){
var outcome = [ProfInfo]()
ref.child("Profiles").child(key).observe(.value, with: { (snapshot) in
let info = ProfInfo(snapshot: snapshot)
outcome.append(info)
//Here
/You are replacing value in self.profInfo
//for the first time when this is called it results In First profile info
//When you reload here first Profile will be shown
//Second time when it is called you again here replaced self.profInfo
//with second Outcome i.e TableView reloads and output shown is only second Profile
//you had initialised a Array self.profInfo = [ProfInfo]()
//But you just replacing array with Single value Actually you need to append data
// I think here is main issue
self.profInfo = outcome
//So try Appending data as
//self.profInfo.append(outcome) instead of self.profInfo = outcome
//Then reload TableView to get both outputs
self.tableView.reloadData()
}, withCancel: nil)
}
Table view showing one content because when table view reloaded then profile info not combine all data. You need to reload the table view after combining all data. This will help you.
// fetch
var profInfo = [ProfInfo]()
func fetchUid(){
guard let uid = Auth.auth().currentUser?.uid else{ return }
ref.child("following").child(uid).observe(.value, with: { (snapshot) in
guard let snap = snapshot.value as? [String:Any] else { return }
snap.forEach({ (key,_) in
self.fetchProf(key: key)
})
// When all key fetched completed the just reload the table view in the Main queue
Dispatch.main.async{
self.tableView.reloadData()
}
}, withCancel: nil)
}
func fetchProf(key: String){
ref.child("Profiles").child(key).observe(.value, with: { (snapshot) in
let info = ProfInfo(snapshot: snapshot)
self.profInfo.append(info) // Here just add the outcome object to profileinfo
}, withCancel: nil)
}
This way no need to handle another array.
I have a tableview that loads data from Firebase, and on load it seems to take ages, around 10-15 seconds before any data is shown in the tableview. it also appears thet the app is frozen while this data is loading.
my function for getting the data is: this is called in viewDidLoad
func getTrackData() {
let result = FIRDatabase.database().reference(withPath: "tracks")
result.observe(.value, with: { snapshot in
var newItems: [newTracks] = []
for item in snapshot.children {
let trackDetails = newTracks(snapshot: item as! FIRDataSnapshot)
newItems.append(trackDetails)
}
self.items = newItems
self.items.sort(by: {$0.distance < $1.distance})
self.tableView.reloadData()
})
}
and my tableview is as follows:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCell(withIdentifier: "TrackCell", for: indexPath) as? TrackCell {
let tr: newTracks!
if inSearchMode {
tr = filteredTrack[indexPath.row]
cell.configureCell(track: tr)
} else {
tr = items[indexPath.row]
cell.configureCell(track: tr)
}
cell.configureCell(track: tr)
cell.completion = {
let coordinate = CLLocationCoordinate2DMake(tr.lat,tr.lon)
let mapItem = MKMapItem(placemark: MKPlacemark(coordinate: coordinate,addressDictionary:nil))
mapItem.name = tr.name
mapItem.openInMaps(launchOptions: [MKLaunchOptionsDirectionsModeKey :MKLaunchOptionsDirectionsModeDriving])
return()
}
cell.completion1 = {
let url = URL(string: tr.link)!
if #available(iOS 10.0, *) {
UIApplication.shared.open(url, options: [:], completionHandler: nil)
} else {
UIApplication.shared.open(url)
}
return()
}
return cell
} else {
return UITableViewCell()
}
}
My question is, is this code written ok, or is there a better way to do it. I have a concern that my function is getting each item and then reloading the tableview, and this may be slowing things down significantly. My data isnt massive, here is an example.
that shows 1 full record, there are 131 of those records in total.
Figured this out now, I had a calculation for distance in miles from current location being worked out with each set of data being loaded. This significantly slowed down the tableview population.
Just need to figure how to do this calculation now, but maybe after the data has loaded
I am trying to implement a like feature in my app using parse. If a user taps the vote up button. The label increases changing the like number in parse side as well. However with my code a user can tap many times to increase the like. I would like to make it detect that user has tapped and make the like button disabled. To do that I have made a class in parse called "Liked". I made a username, imageId both a string column and a likeStatus as a Boolean . However I can't make is so that if a user likes any image it will add new item to it with userId, ImageId and likeStatus.
This is the Collection View code
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("newview", forIndexPath: indexPath) as! NewCollectionViewCell
let item = self.votes[indexPath.row]
// Display the country name
if let value = item["imageText"] as? String {
cell.postsLabel.text = value
}
// Display "initial" flag image
var initialThumbnail = UIImage(named: "question")
cell.postsImageView.image = initialThumbnail
cell.complition = {
self.likeButton(indexPath)
}
if let votesValue = item["votes"] as? Int
{
cell.votesLabel?.text = "\(votesValue)"
}
// Fetch final flag image - if it exists
if let value = item["imageFile"] as? PFFile {
cell.postsImageView.file = value
cell.postsImageView.loadInBackground({ (image: UIImage?, error: NSError?) -> Void in
if error != nil {
cell.postsImageView.image = image
}
})
}
return cell
}
/*
==========================================================================================
Segue methods
==========================================================================================
*/
func likeButton(indexPath:NSIndexPath)
{
let cell = self.collectionView.cellForItemAtIndexPath(indexPath) as! NewCollectionViewCell
let object = self.votes[indexPath.row]
if let likes = object["votes"] as? Int
{
object["votes"] = likes + 1
object.saveInBackgroundWithBlock{ (success:Bool,error:NSError?) -> Void in
println("Data saved")
}
cell.votesLabel?.text = "\(likes + 1)"
}
else
{
object["votes"] = 1
object.saveInBackgroundWithBlock{ (success:Bool,error:NSError?) -> Void in
println("Data saved")
}
cell.votesLabel?.text = "1"
}
}
and this is the cell code
#IBAction func vote(sender: AnyObject) {
if self.complition != nil
{
self.complition!()
}
}
}
Any tips or How am I able to do this in code?Thank you.
The way I did this was by using a class in Parse that I called "UserLikeActivity" or something to that effect, and in it, it had a column pointer to the user that did the liking, a pointer to the actitivy that was liked (in my case it was a post), a type (indicating whether it was an upvote, downvote, follow, etc), and a pointer to the user who created the activity that was liked.
Now, when I was querying Parse to set my tables up, not only did I query the class that contained all the posts, but I also queried this class, which I then saved and used to determine the button state. So for every cell, if the activity had already been liked, I disabled the button. Hopefully this will help you get going in the right direction since you've asked this question about 7 times.