How to drag a static cell into tableView swift? - ios

Question

I have one tableView in my storyBoard where I added 4 static cell into it and my storyBoard look like:
I don't have any dataSource for this tableView because my cells are static.
And I use below code to drag a cell and it is working fine till I scroll a table.
import UIKit
class TableViewController: UITableViewController {
var sourceIndexPath: NSIndexPath = NSIndexPath()
var snapshot: UIView = UIView()
let longPress: UILongPressGestureRecognizer = {
let recognizer = UILongPressGestureRecognizer()
return recognizer
}()
override func viewDidLoad() {
super.viewDidLoad()
longPress.addTarget(self, action: "longPressGestureRecognized:")
self.tableView.addGestureRecognizer(longPress)
self.tableView.allowsSelection = false
}
override func viewWillAppear(animated: Bool) {
self.tableView.reloadData()
}
// MARK: UIGestureRecognizer
func longPressGestureRecognized(gesture: UILongPressGestureRecognizer){
let state: UIGestureRecognizerState = gesture.state
let location:CGPoint = gesture.locationInView(self.tableView)
if let indexPath: NSIndexPath = self.tableView.indexPathForRowAtPoint(location){
switch(state){
case UIGestureRecognizerState.Began:
sourceIndexPath = indexPath
let cell: UITableViewCell = self.tableView .cellForRowAtIndexPath(indexPath)!
//take a snapshot of the selected row using helper method
snapshot = customSnapshotFromView(cell)
//add snapshot as subview, centered at cell's center
var center: CGPoint = cell.center
snapshot.center = center
snapshot.alpha = 0.0
self.tableView.addSubview(snapshot)
UIView.animateWithDuration(0.25, animations: { () -> Void in
center.y = location.y
self.snapshot.center = center
self.snapshot.transform = CGAffineTransformMakeScale(1.05, 1.05)
self.snapshot.alpha = 0.98
cell.alpha = 0.0
}, completion: { (finished) in
cell.hidden = true
})
case UIGestureRecognizerState.Changed:
let cell: UITableViewCell = self.tableView.cellForRowAtIndexPath(indexPath)!
var center: CGPoint = snapshot.center
center.y = location.y
snapshot.center = center
print("location \(location.y)")
//is destination valid and is it different form source?
if indexPath != sourceIndexPath{
//update data source
//I have commented this part because I am not using any dataSource.
// self.customArray.exchangeObjectAtIndex(indexPath.row, withObjectAtIndex: sourceIndexPath.row)
//move the row
self.tableView.moveRowAtIndexPath(sourceIndexPath, toIndexPath: indexPath)
//and update source so it is in sync with UI changes
sourceIndexPath = indexPath
}
if (location.y < 68) || (location.y > 450) {
print("cancelled")
self.snapshot.alpha = 0.0
cell.hidden = false
UIView.animateWithDuration(0.10, animations: { () -> Void in
self.snapshot.center = cell.center
self.snapshot.transform = CGAffineTransformIdentity
self.snapshot.alpha = 0.0
//undo fade out
cell.alpha = 1.0
}, completion: { (finished) in
self.snapshot.removeFromSuperview()
})
}
case UIGestureRecognizerState.Ended:
//clean up
print("ended")
let cell: UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
cell.hidden = false
UIView.animateWithDuration(0.25, animations: { () -> Void in
self.snapshot.center = cell.center
self.snapshot.transform = CGAffineTransformIdentity
self.snapshot.alpha = 0.0
//undo fade out
cell.alpha = 1.0
}, completion: { (finished) in
self.snapshot.removeFromSuperview()
})
break
default:
break
}
}else{
gesture.cancelsTouchesInView = true
}
}
func customSnapshotFromView(inputView: UIView) -> UIView {
// Make an image from the input view.
UIGraphicsBeginImageContextWithOptions(inputView.bounds.size, false, 0)
inputView.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext();
// Create an image view.
let snapshot = UIImageView(image: image)
snapshot.layer.masksToBounds = false
snapshot.layer.cornerRadius = 0.0
snapshot.layer.shadowOffset = CGSize(width: -5.0, height: 0.0)
snapshot.layer.shadowRadius = 5.0
snapshot.layer.shadowOpacity = 0.4
return snapshot
}
}
When I scroll after dragging it looks like:
As you can see cell is not appearing again. I want to drag and drop static cell and I want to save it's position so I will not rearrange again when I scroll.
Sample project for more Info.
This is just a demo project But I have added many elements into my cell and every cell have different UI.

Answer 1

There is a library that does exactly what you are looking to do with a very similar approach. It's called FMMoveTableView but it's for cells with a datasource.
I think that what is causing your problem is that when you move the cells around and then you scroll the datasource from the storyboard is no longer in sync with the table and therefore your cell object can't be redrawn.
I think you should implement your table this way:
Make your 4 cells custom cells.
Subclass each one.
Create an Array with numbers 1 to 4
Reorder the array on long drag
Override cellForRowAtIndexPath to show the right cell for the right number

Answer 2

You can drag uitableview cell from uitableview delegates .......
1) set the table view editing style to none in its delegate.
2) implement table view delegate to enable dragging of cell i.e canMoveRowAtIndexPath methods...

Answer 3

You can create multiple dynamic cells.
You'll just have to dequeue cells with correct identifier.

Answer 4

Are you doing this for layout purposes only, maybe a UICollectionView or a custom made UIScrollView could do the job?
Never the less, I have a solution:
Create a IBOutlet collection holding all your static UITableViewCells
Create a index list to simulate a "data source"
Override the cellForRowAtIndexPath to draw using your own index list
When updating the list order, update the indexList so that the view "remembers" this change
This Table view controller explains it all:
class TableViewController: UITableViewController {
#IBOutlet var outletCells: [UITableViewCell]!
var indexList = [Int]()
override func viewDidLoad() {
super.viewDidLoad()
// Prepare a index list.
// We will move positions in this list instead
// of trying to move the view's postions.
for (index, _) in outletCells.enumerate() {
indexList.append(index)
}
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Use dynamic count, not needed I guess but
// feels better this way.
return outletCells.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
// Use the index path to get the true index and return
// the view on that index in our IBOutlet collection
let realIndexForPos = indexList[indexPath.row]
return outletCells[realIndexForPos]
}
#IBAction func onTap(sender: AnyObject) {
// Simulating your drag n drop stuff here... :)
let swapThis = 1
let swapThat = 2
tableView.moveRowAtIndexPath(NSIndexPath(forItem: swapThis, inSection: 0), toIndexPath: NSIndexPath(forItem: swapThat, inSection: 0))
// Update the indexList as this is the "data source"
// Do no use moveRowAtIndexPath as this is never triggred
// This one line works: swap(&indexList[swapThis], &indexList[swapThat])
// But bellow is easier to understand
let tmpVal = indexList[swapThis]
indexList[swapThis] = indexList[swapThat]
indexList[swapThat] = tmpVal
}
}
To create the IBOutlet use the Interface Builder.
Use the Referencing Outlet Collection on each Table View Cell and drag, for each, to the same #IBOutlet in your controller code.