CODEWITHSUNDEEP
iosxcodeswiftuitableviewswift2
thibaut noah
thibaut noah

Reputation: 1514

Cell text duplicates to another row when autoscrolling (with drag and drop)

so here is the thing, i tried to work my way around with no framework as i wanted to unterstand it. What i wanted to do what implement a drag and drop uitableview with multisection and an autoscroll feature. The issue i ran into is that when autoscrolling back and forth some celles (at least their label names) duplicates on other cells and i really don't understand why.

let indexPath = self.tableView.indexPathForRowAtPoint(currentLongPressTouchLocation)
if indexPath != Drag.sourceIndexPath
{
    // swap the data between the 2 (internal) arrays
  let dataPiece = self.items[Drag.sourceIndexPath.section][Drag.sourceIndexPath.row]
    self.items[indexPath!.section].insert(dataPiece, atIndex: indexPath!.row)
    self.items[Drag.sourceIndexPath.section].removeAtIndex(Drag.sourceIndexPath.row)

    //------=-=-=-=[
    // This line errors when it is uncommented. When I comment it out, the error is gone,
    // and the cells /do/ reorder.. ¯\_(ツ)_/¯
    // swap(&currentList.orderItems[indexPath.row], &currentList.orderItems[Drag.sourceIndexPath.row])
    self.tableView.moveRowAtIndexPath(Drag.sourceIndexPath, toIndexPath: indexPath!)
    Drag.sourceIndexPath = indexPath
    // error is definitly here imo but cannot find it :/
}


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! CustomViewCell

    cell.tag = indexPath.row
    let screenSize: CGRect = UIScreen.mainScreen().bounds
    let screenWidth = screenSize.width
    cell.label.frame = CGRectMake(20, 0, screenWidth - 20, 44)
    cell.textLabel?.text = self.items[indexPath.section][indexPath.row]
    return cell
}

I forgot the init of the customviewcell my bad :

override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
    super.init(style: style, reuseIdentifier: reuseIdentifier)
    let screenSize: CGRect = UIScreen.mainScreen().bounds
    let screenWidth = screenSize.width
    label = UILabel(frame: CGRectMake(20, 0, screenWidth / 2, 44))
    labelBis = UILabel(frame: CGRectMake(20, 20, screenWidth - 20, 20))
    labelBis.textAlignment = NSTextAlignment.Center
    self.contentView.addSubview(label)
    self.contentView.addSubview(labelBis)

}

If anybody could help me on this it would be gladly appreciated, thanks for reading.

Upvotes: 1

Views: 1011

Answers (1)

Abhinav
Abhinav

Reputation: 38162

Data duplication on table view cells happens due to cell re-use in cellForRowAtIndexPath:. You might be calling, dequeueReusableCellWithIdentifier method inside cellForRowAtIndexPath: which pulls out already created cell from the pool (typically when cell 1 disappears and cell 8 is about to show, cell 1 is re-used for cell 8 instead of creating a new cell).

When this happens it is our responsibility to reset the re-used cell content before setting new content. At times, it may happen that your cell label setting code might be in a If condition which is not executing in current context leading to showing the re-used cell's label text.

Please check, I am sure your case would be falling in this.

Upvotes: 4

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