I've a collectionview inside my resizable tablviewCells. Tableview has one cell in each 'n' number of sections. Datasource and delegate of collectionview are set to the tableviewCell. There is an API called on tablview's cellForRowAt, and the result is rendered on the collectionview for each cell. After the result is fetched, a delegate tells the tableview that collectionview is loaded and it should reload that cell without calling the API this time. But the problem is that my collectionview data is repeated after every 2 tableviewCells.
I know prepareForReuse should be override to get rid of cell reuse problems. I've implemented prepareForReuse in my collectionviewCells and set my label.text and imageView.image to nil. However i'm not sure what to add to prepareForReuse for my tableviewCell.
// TableView class
override func viewDidLoad() {
super.viewDidLoad()
storiesSections = [....]
tableView.register(UINib(nibName: "RWFeedTableViewCell", bundle: nil), forCellReuseIdentifier: "reuseIdentifier")
tableView.estimatedRowHeight = 1
tableView.rowHeight = UITableView.automaticDimension
}
override func numberOfSections(in tableView: UITableView) -> Int {
return storiesSections.count
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath) as! RWFeedTableViewCell
if cell == nil {
cell = UITableViewCell(style: UITableViewCell.CellStyle.default, reuseIdentifier: "reuseIdentifier") as! RWFeedTableViewCell
}
cell.delegate = self
cell.fetchData(feedSection: storiesSections[indexPath.section], indexPath: indexPath)
return cell
}
// delegate for tableview reload
func collectionViewDidEnd(updatedFeedSection: FeedSection, indexPath: IndexPath) {
storiesSections[indexPath.section] = updatedFeedSection
tableView.beginUpdates()
tableView.endUpdates()
}
// TableViewCell class
override func awakeFromNib() {
super.awakeFromNib()
initializeCode()
}
func initializeCode() {
// Set layout
self.collectionView.collectionViewLayout = RWWaterfallLayout2()
self.collectionView.register(UINib(nibName: "\(ImageThenTitleViewCell.self)", bundle: nil), forCellWithReuseIdentifier: kImageThenTitleCellID)
self.collectionView.register(UINib(nibName: "\(LeftImageCell.self)", bundle: nil), forCellWithReuseIdentifier: kLeftImageCellID)
self.collectionView.contentInset = UIEdgeInsets(top: 8, left: 8, bottom: 8, right: 8)
self.collectionView.isScrollEnabled = false
self.collectionView.dataSource = self
self.collectionView.delegate = self
}
func fetchData(feedSection: FeedSection, indexPath: IndexPath) {
if feedSection.isLoadComplete {
return
}
if let catID = feedSection.categoryID {
let urlString = URL(string: <urlString>)
let urlRequest = URLRequest(url: urlString!)
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
let task = session.dataTask(with: urlRequest) { (data, response, error) in
if error == nil {
} else {
print(error?.localizedDescription as Any)
}
guard let responseData = data else {
print("Error: did not receive data")
return
}
do {
guard let todo = try JSONSerialization.jsonObject(with: responseData, options: [])as? [String: Any] else {
print("error trying to convert data to JSON")
return
}
print("success convert data to JSON")
DispatchQueue.main.async {
var updatedFeedSection = feedSection
updatedFeedSection.storiesArray? = (todo["data"]! as! Array)
updatedFeedSection.isLoadComplete = true
self.feedSection = updatedFeedSection
self.collectionView.reloadData()
self.collectionView.performBatchUpdates({
}, completion: { (complete) in
self.collectionViewHeightConstraint.constant = self.collectionView.collectionViewLayout.collectionViewContentSize.height + self.collectionView.contentInset.top + self.collectionView.contentInset.bottom
self.delegate?.collectionViewDidEnd(updatedFeedSection: updatedFeedSection, indexPath: indexPath)
})
}
} catch {
print("error trying to convert data to JSON")
return
}
}
task.resume()
}
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if self.feedSection == nil {
return 0
} else {
return (self.feedSection?.storiesArray?.count)!
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let indexForTen = indexPath.item%10
let story = self.feedSection?.storiesArray?[indexPath.item]
if indexForTen == 0 {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: kImageThenTitleCellID, for: indexPath) as! ImageThenTitleViewCell
cell.setupData(story: story!)
return cell
}
else {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: kLeftImageCellID, for: indexPath) as! LeftImageCell
cell.setupData(story: story!)
return cell
}
}
override func prepareForReuse() {
super.prepareForReuse()
}
// Collectionview Cell
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
func setupData(story: Dictionary<String, Any>){
self.storyImage.image = nil // reset the image
let thumbImage = story["image"] as! Dictionary<String, String>
self.storyTitle.text = story["t"] as? String
self.storyImage.downloaded(from: (thumbImage["m"])!)
self.layer.borderColor = UIColor.lightGray.cgColor
self.layer.borderWidth = 1
self.layer.cornerRadius = 8
}
override func prepareForReuse() {
super.prepareForReuse()
storyImage.image = nil
storyTitle.text = nil
}
// FeedSection struct
struct FeedSection {
var categoryID: String?
var storiesArray : [Dictionary<String, Any>]?
var isLoadComplete: Bool
init(categoryID: String) {
self.categoryID = categoryID
self.storiesArray = []
self.isLoadComplete = false
}
}
Currently the 3rd tableviewCell repeats the data of 1st tablviewCell. How to avoid repeating cell data?
Only problem was the feedSection object in TableViewCell. It should be initialized at the time fetchData() is called. And just reload the collectionView if isLoadComplete is true.
Also since isLoadComplete is set on completion handler of URLSession, I set it to true the time API is called. So the same api will not be called while waiting for response. Maybe an enum could be set for api call and api response events on FeedSection. But for now this works.
func fetchData(feedSection: FeedSection, indexPath: IndexPath) {
self.feedSection = feedSection
if self.feedSection.isLoadComplete {
self.collectionView.reloadData()
return
}
if let catID = feedSection.categoryID {
let urlString = URL(string: <urlString>)
let urlRequest = URLRequest(url: urlString!)
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
self.feedSection.isLoadComplete = true
self.delegate?.collectionViewDidEnd(updatedFeedSection: self.feedSection, indexPath: indexPath)
let task = session.dataTask(with: urlRequest) { (data, response, error) in
if error == nil {
} else {
print(error?.localizedDescription as Any)
}
guard let responseData = data else {
print("Error: did not receive data")
return
}
do {
guard let todo = try JSONSerialization.jsonObject(with: responseData, options: [])as? [String: Any] else {
print("error trying to convert data to JSON")
return
}
print("success convert data to JSON")
DispatchQueue.main.async {
self.feedSection.storiesArray? = (todo["data"]! as! Array)
self.feedSection.isLoadComplete = true
self.collectionView.reloadData()
self.collectionView.performBatchUpdates({
}, completion: { (complete) in
self.collectionViewHeightConstraint.constant = self.collectionView.collectionViewLayout.collectionViewContentSize.height + self.collectionView.contentInset.top + self.collectionView.contentInset.bottom
self.delegate?.collectionViewDidEnd(updatedFeedSection: self.feedSection, indexPath: indexPath)
})
}
} catch {
print("error trying to convert data to JSON")
return
}
}
task.resume()
}
}