How to correctly insert UILabels into each tebleview cell - uitableview

Question

I am having a problem creating UILabels to insert into my tableview cells. They insert fine and display fine, the problem comes in when I go to scroll. The ordering of the row's goes haywire and looses it's initial order. For instance, at the beginning, the idLabel's cell text, goes from 0 > 14, in sequential order. After scrolling down and back up, the order could be anything, 5, 0, 10, 3 etc.
Any ideas on why this is happening? I am presuming my attempts to update the label's after cell creation is wrong.
var idArr: NSMutableArray!
// In init function
self.idArr = NSMutableArray()
for ind in 0...14 {
self.idArr[ind] = ind
}
// Create the tableview cells
internal func tableView( tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath ) -> UITableViewCell {
if cell == nil {
let id = self.idArr[indexPath.row] as Int
cell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "cell" )
// Id
let idLabel: UILabel = UILabel( frame: CGRectZero )
idLabel.text = String( id )
idLabel.textColor = UIColor.blackColor()
idLabel.tag = indexPath.row
idLabel.sizeToFit()
idLabel.layer.anchorPoint = CGPointMake( 0, 0 )
idLabel.layer.position.x = 15
idLabel.layer.position.y = 10
idLabel.textAlignment = NSTextAlignment.Center
cell?.addSubview( idLabel )
}
// Update any labels text string
for obj: AnyObject in cell!.subviews {
if var view = obj as? UILabel {
if view.isKindOfClass( UILabel ) {
if view.tag == indexPath.row {
view.text = String( id )
}
}
}
}
// Return the cell
return cell!
}
Thanks for any assistance, I can't see the wood for the trees anymore.

Answer 1

The logic in your cell updating looks off. You are checking that a tag you set at initialization is equal to the index path's row but because the cells should be reused this will not always be the case. If you just remove that tag checking line in the for loop it should work fine.
Also, I'm not sure why you are checking ifKindOfClass after you have optionally cast the view as a label anyway.
To prevent accidentally updating Apple's views you would be better off adding a constant tag for the label and pulling the label by that tag instead of looping through all of the subviews.
This is clearly not the actual code you are running since the id variable is not in the proper scope and there is no definition of cell. I've added proper dequeueing and move the id variable to something that works. I'm assuming you are doing those in your actual code.
internal func tableView( tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath ) -> UITableViewCell {
let labelTag = 2500
let id = self.idArr[indexPath.row] as Int
var cell = tableView.dequeueReusableCellWithIdentifier("cell")
if cell == nil {
cell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "cell" )
// Id
let idLabel: UILabel = UILabel( frame: CGRectZero )
idLabel.text = String( id )
idLabel.textColor = UIColor.blackColor()
idLabel.tag = labelTag
idLabel.sizeToFit()
idLabel.layer.anchorPoint = CGPointMake( 0, 0 )
idLabel.layer.position.x = 15
idLabel.layer.position.y = 10
idLabel.textAlignment = NSTextAlignment.Center
cell?.addSubview( idLabel )
}
// Update any labels text string
if let view = cell?.viewWithTag(labelTag) as? UILabel {
view.text = String( id )
}
// Return the cell
return cell!
}