iOS Swift TableviewCell issue - ios

Question

I have a strange problem with tableView cell.
when I scroll tableView and cell disappear and back again to the cell I understand that tableView add similar cell exactly on cell.
for example look at the picture . 3 exact text add on each other.
cellForRowAtIndexPath function :
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
if indexPath.row == 0 {
let reviewNumber = UILabel()
if (self.book.review_count == 0) {
reviewNumber.text = "\(self.lang.book["no_review"]!)"
}
if (self.book.review_count > 0) {
reviewNumber.text = "\(self.book.review_count!) \(self.lang.general["review"]!)"
}
reviewNumber.textAlignment = .Right
reviewNumber.font = UIFont(name: "Vazir", size: 14)
reviewNumber.numberOfLines = 0
reviewNumber.translatesAutoresizingMaskIntoConstraints = false
reviewNumber.textColor = UIColor.grayColor()
cell.contentView.addSubview(reviewNumber)
let voteIcon = UIImageView()
voteIcon.image = UIImage(named: "vote-icn")
voteIcon.translatesAutoresizingMaskIntoConstraints = false
cell.contentView.addSubview(voteIcon)
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[v0(24)]-|",options: [],metrics: nil,views: ["v0" : voteIcon]))
let reviewIcon = UIImageView()
reviewIcon.image = UIImage(named: "review-icn")
reviewIcon.translatesAutoresizingMaskIntoConstraints = false
cell.contentView.addSubview(reviewIcon)
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[v0(24)]-|",options: [],metrics: nil,views: ["v0" : reviewIcon]))
let voteNumber = UILabel()
voteNumber.text = " ۴.۵ از ۱۶۵۴رأی"
voteNumber.textAlignment = .Left
voteNumber.font = UIFont(name: "Vazir", size: 14)
voteNumber.numberOfLines = 0
voteNumber.translatesAutoresizingMaskIntoConstraints = false
voteNumber.textColor = UIColor.grayColor()
cell.contentView.addSubview(voteNumber)
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-3-[v0]-3-|",options: [],metrics: nil,views: ["v0" : reviewNumber]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-3-[v0]-3-|",options: [],metrics: nil,views: ["v0" : voteNumber]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-35-[v0]-8-[v1(25)]",options: [],metrics: nil,views: ["v0" : voteNumber, "v1" : voteIcon, "v2" : reviewNumber, "v3" : reviewIcon]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[v2]-8-[v3(25)]-35-|",options: [],metrics: nil,views: ["v0" : voteNumber, "v1" : voteIcon, "v2" : reviewNumber, "v3" : reviewIcon]))
}
if indexPath.row == 1 {
let userBookStatusButtn = UIButton(type: .Custom)
userBookStatusButtn.setTitle("خواهم خواند", forState: .Normal)
userBookStatusButtn.alpha = 0.2
userBookStatusButtn.titleLabel?.font = UIFont(name: "Vazir", size: 14)
userBookStatusButtn.setTitleColor(UIColor.whiteColor(), forState: .Normal)
// userBookStatusButtn.setImage(UIImage(named: "vote-icn"), forState: .Normal)
userBookStatusButtn.translatesAutoresizingMaskIntoConstraints = false
userBookStatusButtn.backgroundColor = UIColor(red:0.0/256.0 ,green:150.0/256.0, blue:136.0/256.0 ,alpha:1 )
cell.contentView.addSubview(userBookStatusButtn)
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-20-[v0(48)]-20-|",options: [],metrics: nil,views: ["v0" : userBookStatusButtn]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-35-[v0]-35-|",options: [],metrics: nil,views: ["v0" : userBookStatusButtn]))
}
if indexPath.row == 2 {
let topBorder = UIView()
topBorder.translatesAutoresizingMaskIntoConstraints = false
topBorder.backgroundColor = UIColor(white: 0.5, alpha: 0.5)
cell.contentView.addSubview(topBorder)
let bottomBorder = UIView()
bottomBorder.translatesAutoresizingMaskIntoConstraints = false
bottomBorder.backgroundColor = UIColor(white: 0.5, alpha: 0.5)
cell.contentView.addSubview(bottomBorder)
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 5
paragraphStyle.baseWritingDirection = .RightToLeft
guard let descriptionStr = self.book.description else {return cell}
let attrString = NSMutableAttributedString(string: descriptionStr)
attrString.addAttribute(NSParagraphStyleAttributeName, value:paragraphStyle, range:NSMakeRange(0, attrString.length))
let description = UILabel()
description.attributedText = attrString
description.textAlignment = .Justified
description.font = UIFont(name: "Vazir", size: 14)
description.numberOfLines = 0
description.translatesAutoresizingMaskIntoConstraints = false
description.lineBreakMode = NSLineBreakMode.ByWordWrapping
cell.contentView.addSubview(description)
let title = UILabel()
title.text = "\(self.lang.book["summery"]!)"
title.alpha = 0.2
title.textAlignment = .Center
title.font = UIFont(name: "Vazir-Bold", size: 16)
title.translatesAutoresizingMaskIntoConstraints = false
cell.contentView.addSubview(title)
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-[v0]-|",options: [.AlignAllCenterX],metrics: nil,views: ["v0" : title]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-20-[v0]-20-|",options: [],metrics: nil,views: ["v0" : description]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-8-[v1]-44-[v0]",options: [],metrics: nil,views: ["v0" : description,"v1" : title ]))
cell.contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[v0]-8-|",options: [],metrics: nil,views: ["v0" : description,"v1" : title ]))
}
cell.textLabel?.text = nil
return cell
}
I get data from son file with Alamofire and reloadData :
func tableRefresh()
{
dispatch_async(dispatch_get_main_queue(), {
self.bookDetailTableView.reloadData()
})
}
what's my problem?
thanks guys.

Answer 1

You made a classical error when using iOS cells.
(I am a teacher, so I see this kind of error frequently... don't worry..)
some Considerations:
1) NEVER add a label to a cell. Doing so, very time a cell is reused, previous label stays here, and a new label is added
2) as label are transparent, you will see all text overlapped..
3) You are leaking memory, as no one will detach/ release labels.
so the way can be:
A)Simple for simple case
use TAGS, as Apple did on old days of cells..
(code i
make some defines:
let TEXT_TAG = 2000
add label if not present, if present get it vi TAG:
let cell = tableView.dequeueReusableCell(withIdentifier: REUSE, for: indexPath )
let text = "my text..."
if let label = cell.viewWithTag(TEXT_TAG) as? UILabel{
label.text = text
}else{
let frame = CGRect(x: 100, y: 20, width: 50, height: 50)
let label = UILabel(frame: frame)
label.text = text
cell.addSubview(label)
}
B) make a custom cell...
class CustomViewCell: UITableViewCell {
var label: UILabel?
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
let frame = CGRect(x: 100, y: 20, width: 50, height: 50)
let label = UILabel(frame: frame)
self.addSubview(label)
}
in controller simply:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: REUSE,
for: indexPath ) as! CustomViewCell
cell.label = "my text"

Answer 2

I get your problem,you get the cell from tableView reuseable pool.The first problem,if you want change UITableViewCell View,you need to creat a son class of it.I get a function to fix it.
I use Stackoverflow first time,I don't know where can I put my code,so I write it under this sentence.
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
for let item in cell.contentView.subviews {
item.removeFromSuperView();
}
And then using your code,it should help you.