How to use CAGradientLayers on UITableViewCell - ios

Question

I am running into a problem with using CAGradientLayers on my UITableViewCells. What I am attempting to do is simulate what actionsForRowAtIndexPath does, but I want to use a custom action view rather than just setting a background color.
So, my plan of action is in my UITableViewCell I have laid out a UIView (the action view) that is hidden beneath another UIView (main content view) that are both in the default contentView of UITableViewCell.
So in my 'cellForRowAt' tableView function, I have this code:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomTableViewCell", for: indexPath) as! CustomTableViewCell
// Set Up Gradient
let actionGradient = CUSTOM_GRADIENTS.blueToGreen!
actionGradient.frame = cell.actionView.frame
// Add Gradient to ActionView
cell.actionView.insertSubLayer(actionGradient, at: 0)
return cell
}
And just for a reference my CUSTOM_GRADIENTS is a class that is initialized at in the ApplicationDelegate:
class safeGradiants {
var blueToGreen: CAGradientLayer!
init() {
self.blueToGreen = CAGradientLayer()
self.blueToGreen.colors = [UIColor.blue, UIColor.]
self.blueToGreen.startPoint = CGPoint(x: 0.0, y: 0.5)
self.blueToGreen.endPoint = CGPoint(x: 1.0, y: 0.5)
}
}
Where the error occurs is when my tableView is loaded, the only cell with the gradient is the LAST CELL in the table view. I can only presume this has something to do with the reuse of cells, but I can't for the life of me figure out how to fix it.
Any ideas on what I need to do to get this gradient showing on the actionView for all the cells?

Answer 1

After a little bit of messing around, I figured out my problem lied in my safeGradients class. Since I was using one global instance of that class, I was un able to reuse the same variable blueToGreen.
The solution to this is instead of creating a class and having one global instance of that class, is to create an extension of CAGradientLayer that hosts subclass functions. In other words, I changed this code:
class safeGradiants {
var blueToGreen: CAGradientLayer!
init() {
self.blueToGreen = CAGradientLayer()
self.blueToGreen.colors = [UIColor.blue, UIColor.]
self.blueToGreen.startPoint = CGPoint(x: 0.0, y: 0.5)
self.blueToGreen.endPoint = CGPoint(x: 1.0, y: 0.5)
}
}
into this code:
extension CAGradientLayer {
class var blueToGreen: CAGradientLayer {
let blueToGreen = CAGradientLayer()
blueToGreen.colors = [UIColor.blue, UIColor.green]
blueToGreen.startPoint = CGPoint(x: 0.0, y: 0.5)
blueToGreen.endPoint = CGPoint(x: 1.0, y: 0.5)
return blueToGreen
}
}