swift reuse cell custom view issue - ios

Question

I have a custom view(tagListView) inside a custom tableview cell.
When I call addTag to cell.tagListView inside "cellForRowAt", it adds a tag for every cell.
How do I add tag only for that cell? I tried to keep a count so I only add tags to those which don't have tags. But it appears that this count is the same for all cells? I know this has something to do with reusable cell.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = topicListTableView.dequeueReusableCell(withIdentifier: "TopicListTableCell", for: indexPath)
if let myCell = cell as? TopicListTableCell {
if let model=topicListModel{
let t=model.topics[(indexPath.row)]
if let subject=t.subject{
let (tags,title)=util().getTag(subject: subject)
myCell.subject.text=title
if(myCell.tagCount==0){
myCell.tagList.addTags(tags)
myCell.tagCount+=1
}
}
myCell.content.text=t.content
myCell.authorTime.text=t.author
if let replynum=t.replies{
myCell.commentNum.text=String(replynum)
}
if let upvoteNum=t.score{
myCell.upVote.text=String(upvoteNum)
}
if indexPath.row%2==1{
myCell.background.backgroundColor=util().lightyellow
}else{
myCell.background.backgroundColor=util().darkeryellow
}
}
}
return cell
}
code for cell:
class TopicListTableCell: UITableViewCell{
#IBOutlet weak var content: UILabel!
#IBOutlet weak var upVote: UILabel!
#IBOutlet weak var commentNum: UILabel!
#IBOutlet weak var subject: UILabel!
#IBOutlet weak var authorTime: UILabel!
#IBOutlet weak var background: UIView!
#IBOutlet weak var tagList: TagListView!
var tagCount = 0
}

Answer 1

As dfd already stated, your approach isn't the right one because of the way UITableViews are working in iOS.
You should have one dataSource for your tableView (some array or dictionary) which contains all the information needed to present the cells the way you want.
So I would make a struct which contains all information I need to fill one cell and then make an array of these structs to fill all cells with the information they need.
Something like this:
// In your model:
struct TopicItem {
let topic: Topic
let tags: [Tag]
let title: String
}
var topicItems = [TopicItem]()
// This is function is only a draft, so you get a better idea what i mean
func updateTopicItems() {
topicItems.removeAll()
for topic in topics {
let tags: [Tag]
let title: String
if let subject = topic.subject {
// I would refactor this function, it is called getTag() but it returns tags and title. Kinda confusing
(tags,title) = util().getTag(subject: subject)
} else {
tags = [Tag]()
title = ""
}
topicItems.append(TopicItem(topic: topic, tags: tags, title: title))
}
}
I also have added some refactoring and comments which will hopefully help you to keep your code clean and maintainable in the future :)
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// cell can be force unwrapped, it will never be something different than a TopicListTableCell, unless you change your code
// and even then you want a crash, so you find the error fast (crash will only occur during development)
let cell = topicListTableView.dequeueReusableCell(withIdentifier: "TopicListTableCell", for: indexPath) as! TopicListTableCell
guard let model = topicListModel else { return cell } // If there is no model, there is nothing to do
let topicItem = model.topicItems[(indexPath.row)]
let t = topicItem.topic
cell.subject.text = topicItem.title
// You should replace the addTags() function with a setTags() function, otherwise you will get more and more tags every time you present the cell
cell.tagList.addTags(topicItem.tags)
cell.content.text = t.content
cell.authorTime.text = t.author
if let replynum = t.replies {
cell.commentNum.text = String(replynum)
} else {
// Because cells are getting reused, you need to always set all fields, otherwise you get cells with content from other cells
cell.commentNum.text = ""
}
if let upvoteNum = t.score {
cell.upVote.text = String(upvoteNum)
} else {
// Again always set all fields
cell.upVote.text = ""
}
if indexPath.row %2 == 1 {
cell.background.backgroundColor=util().lightyellow
} else {
cell.background.backgroundColor=util().darkeryellow
}
return cell
}