Swift - fading cells in a UITableView

Question

I am having problems with my UITableView in swift on Xcode 6:

I want my UITableView cells to disappear in / out when appearing / disappearing.

I searched a lot on the Internet for fading animations, but I did not find what I wanted because it is based on duration animations.

I think I need an alpha based mask? I'm not a soup, and I don’t even know what to create ...

I have a UIViewController containing a tableView and some empty space (for now) up and down from the UITableView.

Thank you for your help!

Best

Anatole

Answer 1

animateWithDuration , fade in/out : .

, :

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    var cell = self.tableView.dequeueReusableCellWithIdentifier("cell") as UITableViewCell

    cell.textLabel?.text = self.items[indexPath.row]
    cell.backgroundColor = UIColor.grayColor()
    cell.alpha = 0

    UIView.animateWithDuration(2, animations: { cell.alpha = 1 })

    return cell
}

EDIT:

alpha, y, , , , :

func scrollViewDidScroll(scrollView: UIScrollView) {

    for cell in tableView.visibleCells() as [UITableViewCell] {

        var point = tableView.convertPoint(cell.center, toView: tableView.superview)
        cell.alpha = ((point.y * 100) / tableView.bounds.maxY) / 100
    }
}

Answer 2

, , , , :

func scrollViewDidScroll(_ scrollView: UIScrollView) {

    let cellCount = tableView.visibleCells.count
    let alphaInterval:CGFloat = 1.0 / CGFloat(cellCount / 2)

    for (index,cell) in (tableView.visibleCells as [UITableViewCell]).enumerated() {

        if index < cellCount / 2 {
            cell.alpha = CGFloat(index) * alphaInterval
        } else {
            cell.alpha = CGFloat(cellCount - index) * (alphaInterval)
        }
    }
}

:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell()
    cell.textLabel?.text = countries[indexPath.row].uppercased()
    cell.textLabel?.textColor = .white
    cell.backgroundColor = .clear
    cell.alpha = 0.25

    UIView.animate(withDuration: 0.5, animations: {
        cell.alpha = 1 
    })

    return cell
}

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