Drag and Drop swap with Swift 2.0 - drag-and-drop

Question

I'm using a tableView and need to enable swapping items by dragging and dropping.
I'm mostly there but stuck on one problem. The item that is dragged to is not swapped with the item that is dragged from. Instead the new dragged item is added on top of the existing item and it simply shifts the existing item down one row below that.
case UIGestureRecognizerState.Ended:
var center = My.cellSnapshot!.center
center.y = locationInView.y
My.cellSnapshot!.center = center
if ((indexPath != nil) && (indexPath != Path.initialIndexPath)) {
//check to see if this is a valid place to swap
var numberOfSlots:Int = 0 //the number of valid positions to swap
numberOfSlots = thePlayers[Path.initialIndexPath!.row].SwapPosition.count
for index in 1...numberOfSlots {
if thePlayers[Path.initialIndexPath!.row].SwapPosition[index - 1] == thePlayers[indexPath!.row].PlayerPosition {
//this is a valid swap
print("Swap it!")
OkToSwap = true
break
}
else {
print (thePlayers[Path.initialIndexPath!.row].SwapPosition[index - 1])
}
}
}
if OkToSwap == true { //if this is a valid slot for a swap, then swap it.
// swap(&itemsArray[indexPath!.row], &itemsArray[Path.initialIndexPath!.row])
//***TODO: Add Webservice call to swap on the website***
//move the selectedRow to the original (dragged from) position
tableView.moveRowAtIndexPath(Path.initialIndexPath!, toIndexPath: indexPath!)
My.cellSnapshot?.alpha = 0.0
let cell = tableView.cellForRowAtIndexPath(Path.initialIndexPath!) as UITableViewCell!
cell.alpha = 1
}
//put it back
let cell = tableView.cellForRowAtIndexPath(indexPath!) as UITableViewCell!
cell.hidden = false
cell.alpha = 0.0
UIView.animateWithDuration(0.25, animations: { () -> Void in
My.cellSnapshot!.center = originalCenter
My.cellSnapshot!.transform = CGAffineTransformIdentity
My.cellSnapshot!.alpha = 0.0
cell.alpha = 1.0
}, completion: { (finished) -> Void in
if finished {
Path.initialIndexPath = nil
My.cellSnapshot!.removeFromSuperview()
My.cellSnapshot = nil
}
})
default:
let cell = tableView.cellForRowAtIndexPath(Path.initialIndexPath!) as UITableViewCell!
cell.hidden = false
cell.alpha = 0.0
// Clean up.
UIView.animateWithDuration(0.25, animations: { () -> Void in
My.cellSnapshot!.center = cell.center
My.cellSnapshot!.transform = CGAffineTransformIdentity
My.cellSnapshot!.alpha = 0.0
cell.alpha = 1.0
}, completion: { (finished) -> Void in
if finished {
Path.initialIndexPath = nil
My.cellSnapshot!.removeFromSuperview()
My.cellSnapshot = nil
}
})
}
}
any idea how to do a true swap of rows using Swift 2.0 - I've found a few sample code snippets but syntax changes have made them not work and I'm stuck.

Answer 1

I was able to get this bit working with Swift 2.0
func snapshopOfCell(inputView: UIView) -> UIView {
UIGraphicsBeginImageContextWithOptions(inputView.bounds.size, false, 0.0)
inputView.layer.renderInContext(UIGraphicsGetCurrentContext())
let image = UIGraphicsGetImageFromCurrentImageContext() as UIImage
UIGraphicsEndImageContext()
let cellSnapshot : UIView = UIImageView(image: image)
cellSnapshot.layer.masksToBounds = false
cellSnapshot.layer.cornerRadius = 0.0
cellSnapshot.layer.shadowOffset = CGSizeMake(-5.0, 0.0)
cellSnapshot.layer.shadowRadius = 5.0
cellSnapshot.layer.shadowOpacity = 0.4
return cellSnapshot
}
// MARK: Gesture Methods
func longPressGestureRecognized(gestureRecognizer: UIGestureRecognizer) {
let longPress = gestureRecognizer as! UILongPressGestureRecognizer
let state = longPress.state
var locationInView = longPress.locationInView(tableView)
var indexPath = tableView.indexPathForRowAtPoint(locationInView)
struct My {
static var cellSnapshot : UIView? = nil
}
struct Path {
static var initialIndexPath : NSIndexPath? = nil
}
switch state {
case UIGestureRecognizerState.Began:
if indexPath != nil {
Path.initialIndexPath = indexPath
let cell = tableView.cellForRowAtIndexPath(indexPath!) as UITableViewCell!
My.cellSnapshot = snapshopOfCell(cell)
var center = cell.center
My.cellSnapshot!.center = center
My.cellSnapshot!.alpha = 0.0
tableView.addSubview(My.cellSnapshot!)
UIView.animateWithDuration(0.25, animations: { () -> Void in
center.y = locationInView.y
My.cellSnapshot!.center = center
My.cellSnapshot!.transform = CGAffineTransformMakeScale(1.05, 1.05)
My.cellSnapshot!.alpha = 0.98
cell.alpha = 0.0
}, completion: { (finished) -> Void in
if finished {
cell.hidden = true
}
})
}
break
case UIGestureRecognizerState.Changed:
var center = My.cellSnapshot!.center
center.y = locationInView.y
My.cellSnapshot!.center = center
if ((indexPath != nil) && (indexPath != Path.initialIndexPath)) {
//------=-=-=-=[
// This line errors when it is uncommented. When I comment it out, the error is gone,
// and the cells /do/ reorder.. ¯\_(ツ)_/¯
//swap(&itemsArray[indexPath!.row], &itemsArray[Path.initialIndexPath!.row])
tableView.moveRowAtIndexPath(Path.initialIndexPath!, toIndexPath: indexPath!)
Path.initialIndexPath = indexPath
}
break
default:
let cell = tableView.cellForRowAtIndexPath(Path.initialIndexPath!) as UITableViewCell!
cell.hidden = false
cell.alpha = 0.0
UIView.animateWithDuration(0.25, animations: { () -> Void in
My.cellSnapshot!.center = cell.center
My.cellSnapshot!.transform = CGAffineTransformIdentity
My.cellSnapshot!.alpha = 0.0
cell.alpha = 1.0
}, completion: { (finished) -> Void in
if finished {
Path.initialIndexPath = nil
My.cellSnapshot!.removeFromSuperview()
My.cellSnapshot = nil
}
})
break
}//.switch
}// .longPressGestureRecognized