Is it possible to use UItableViewCell in ASTableView? - ios

It there a way to use both UITableViewCell and ASCellNode in the same UITableView ?
I have many cells but only some of them have performance issues and AsyncDisplayKit works very well with them. I'm wondering if I have to convert all my UITableViewCell's subclasses in order to use them in an ASTableView.

I've got it working using this initializer in AsyncDisplayKit v2.4, Swift:
ASCellNode(viewControllerBlock: { () -> UIViewController }, didLoad: { (ASDisplayNode) -> Void })
Here's a working example:
func tableNode(_ tableNode: ASTableNode, nodeBlockForRowAt indexPath: IndexPath) - > ASCellNodeBlock {
let content = self.contentList[indexPath.row]
// Return the old cell only for specific rows
if content.type == "MyOldContentThatUsesUITableViewCell" {
return {
// Load OldContentCell through a view block on the main thread
let cellHeight: CGFloat = 367.0
let cellNode = ASCellNode(viewControllerBlock: { () - > UIViewController in
let viewController = UIViewController()
// Load a cell using xib
guard let cell = Bundle.main.loadNibNamed("OldContentCell", owner: self, options: nil) ? [0] as ? OldContentCell else {
return viewController
}
// Since it's on the main thread, we can use UIScreen to get the full width
cell.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: cellHeight)
viewController.view.addSubview(cell)
return viewController
}, didLoad: nil)
// Width here doesn't really matter.. it will try and expand the cell's width
// to the ASTableNode's width
cellNode.style.preferredSize = CGSize(width: 100.0, height: cellHeight)
return cellNode
}
}
// Return a real ASCellNode totally managed by AsyncDisplayKit
let cellNodeBlock: () -> ASCellNode = {
// My subclass of ASCellNode
return ContentCellNode(content: content, contentIndex: indexPath.row)
}
return cellNodeBlock
}
I have also tried using the view block instead of view controller block that did not work.. the block never got executed:
ASCellNode(viewBlock: { () -> UIView })

Related

Swift: Delay loading animations in collection view?

I have not seen this topic posted anywhere else - I have built an iMessage app that uses a collecitonview to hold a bunch of MSStickerViews. These stickers are animated.
My problem is that while the app itself appears to load when you first open, there is a noticeable delay before one is able to touch a sticker/interact with the app, and before the MSStickers begin animating. I am not sure whether this is a matter of the order of functions being called but I can't find a way to improve/fix this.
My MSStickers are added to collection view cells here:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// get a reference to our storyboard cell
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "stickerCell", for: indexPath as IndexPath) as! StickerCollectionViewCell
and in a separate Cell class I then add the sticker view and set it to .startAnimating().
The delay is about 5-6 seconds. How can I reduce this? Is this possible?
Animation/sticker code:
for (animal, atlas) in animalsAnim {
animalsAnim[animal] = getImagesForAnimals(animal: animal, allSticks: allStickers)
addSticker(images: animalsAnim[animal]!, name: animal)
}
func addSticker(images: [UIImage], name: String)
{
let sticker: MSSticker
do {
try sticker=MSSticker(images: images, format: .apng, frameDelay: 0.95/14.0, numberOfLoops: 0, localizedDescription: name)
}catch MSStickerAnimationInputError.InvalidDimensions {
fatalError("ERROR: Dimens")
}catch MSStickerAnimationInputError.InvalidStickerFileSize {
fatalError("ERROR: Size")
} catch { fatalError("other error:\(error)") }
var stickerSize = CGSize()
if (UIDevice.current.iPhone5orBefore)
{
stickerSize = CGSize(width: view.bounds.width*0.38, height: view.bounds.width*0.38)
}
else {
stickerSize = CGSize(width: view.bounds.width*0.4, height: view.bounds.width*0.4)
}
let stickerView = InstrumentedStickerView(frame: CGRect(origin: CGPoint(x: 0,y :0), size: stickerSize))
stickerView.sticker = sticker
stickerView.delegate = self
stickerPack.append(stickerView)
}
The sticker view is then added and begun animating in a separate cell class.

Custom pop animation to a UICollectionViewController doesn't work

I have a collection view called ProfileCollectionViewController for collection of images.
When clicked on an image it presents a HorizontalProfileViewController which displays images in full screen.
When back button is pressed on HorizontalProfileViewController I want the full screen image to animate back to a thumbnail in ProfileViewController. I pass the selected index path from ProfileViewController as initialIndexPath to HorizontalProfileViewController so that the position of thumbnail is known. Below is my transition animation code
import UIKit
class SEHorizontalFeedToProfile: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
return 0.2
}
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
if let profileVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) as? SEProfileGridViewController, horizontalFeedVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey) as? SEProfileHorizontalViewController, containerView = transitionContext.containerView() {
let duration = transitionDuration(transitionContext)
profileVC.collectionView?.reloadData()
if let indexPath = horizontalFeedVC.initialIndexPath {
let cell = profileVC.collectionView?.cellForItemAtIndexPath(indexPath)
print(indexPath)
let imageSnapshot = horizontalFeedVC.view.snapshotViewAfterScreenUpdates(false)
let snapshotFrame = containerView.convertRect(horizontalFeedVC.view.frame, fromView: horizontalFeedVC.view)
imageSnapshot.frame = snapshotFrame
horizontalFeedVC.view.hidden = true
profileVC.view.frame = transitionContext.finalFrameForViewController(profileVC)
containerView.insertSubview(profileVC.view, belowSubview: horizontalFeedVC.view)
containerView.addSubview(imageSnapshot)
UIView.animateWithDuration(duration, animations: {
var cellFrame = CGRectMake(0, 0, 0, 0)
if let theFrame = cell?.frame {
cellFrame = theFrame
}
let frame = containerView.convertRect(cellFrame, fromView: profileVC.collectionView)
imageSnapshot.frame = frame
}, completion: { (succeed) in
if succeed {
horizontalFeedVC.view.hidden = false
// cell.contentView.hidden = false
imageSnapshot.removeFromSuperview()
transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
}
})
}
}
}
}
I put breakpoints and found out that in the code
let cell = profileVC.collectionView?.cellForItemAtIndexPath(indexPath)
the cell is nil. I don't understand why it would be nil. Please help me. I thank you in advance.
The profileVC is a subclass of UICollectionViewController
PS: Please check out the following project that does exactly the same thing without any issues. I tried to mimic it but it doesn't work on mine.
https://github.com/PeteC/InteractiveViewControllerTransitions
As was pointed out in the comments on the question, the cell is set to nil because the cell is not visible. Since your HorizontalProfileViewController allows scrolling to other pictures it is possible to scroll to an image that has not yet had a UICollectionViewCell created for it in your ProfileCollectionViewController.
You can remedy this by scrolling to where the current image should be on the UICollectionView. You say that initialIndexPath is initially the indexPath of the image that was first selected. Assuming you update that as the user scrolls to different images so that it still accurately represents the on screen image's indexPath, we can use that to force the UICollectionView to scroll to the current cell if necessary.
With a few tweaks to your code this should give you the desired effect:
import UIKit
class SEHorizontalFeedToProfile: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
return 0.2
}
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
if let profileVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) as? SEProfileGridViewController, horizontalFeedVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey) as? SEProfileHorizontalViewController, containerView = transitionContext.containerView() {
let duration = transitionDuration(transitionContext)
//profileVC.collectionView?.reloadData() //Remove this
if let indexPath = horizontalFeedVC.initialIndexPath {
var cell = profileVC.collectionView?.cellForItemAtIndexPath(indexPath) //make cell a var so it can be reassigned if necessary
print(indexPath)
if cell == nil{ //This if block is added. Again it is crucial that initialIndexPath was updated as the user scrolled.
profileVC.collectionView?.scrollToItemAtIndexPath(horizontalFeedVC.initialIndexPath, atScrollPosition: UICollectionViewScrollPosition.CenteredVertically, animated: false)
profileVC.collectionView?.layoutIfNeeded() //This is necessary to force the collectionView to layout any necessary new cells after scrolling
cell = profileVC.collectionView?.cellForItemAtIndexPath(indexPath)
}
let imageSnapshot = horizontalFeedVC.view.snapshotViewAfterScreenUpdates(false)
let snapshotFrame = containerView.convertRect(horizontalFeedVC.view.frame, fromView: horizontalFeedVC.view)
imageSnapshot.frame = snapshotFrame
horizontalFeedVC.view.hidden = true
profileVC.view.frame = transitionContext.finalFrameForViewController(profileVC)
containerView.insertSubview(profileVC.view, belowSubview: horizontalFeedVC.view)
containerView.addSubview(imageSnapshot)
UIView.animateWithDuration(duration, animations: {
var cellFrame = CGRectMake(0, 0, 0, 0)
if let theFrame = cell?.frame {
cellFrame = theFrame
}
let frame = containerView.convertRect(cellFrame, fromView: profileVC.collectionView)
imageSnapshot.frame = frame
}, completion: { (succeed) in
if succeed {
horizontalFeedVC.view.hidden = false
// cell.contentView.hidden = false
imageSnapshot.removeFromSuperview()
transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
}
})
}
}
}
Now if the current UICollectionViewCell is not yet created it:
Scrolls so the indexPath of the cell is centered on the view
Forces the UICollectionView to layout its subviews which creates any UITableViewCells that are necessary
Asks for the UITableViewCell again, but this time it should not be nil

Swiping left to create a new collectionViewCell

I'm trying to implement a smoother way for a use to add new collectionViewCells for myCollectionView (which only shows one cell at a time). I want it to be something like when the user swipes left and if the user is on the last cell myCollectionView inserts a new cell when the user is swiping so that the user swipes left "into" the cell. And also I only allow the user to scroll one cell at a time.
EDIT:
So I think it is a bit hard to describe it in words so here is a gif to show what I mean
So in the past few weeks I have been trying to implement this in a number of different ways, and the one that I have found the most success with is by using the scrollViewWillEndDragging delegate method and I have implemented it like this:
func scrollViewWillEndDragging(scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
// Getting the size of the cells
let flowLayout = myCollectionView.collectionViewLayout as! UICollectionViewFlowLayout
let cellWidth = flowLayout.itemSize.width
let cellPadding = 10.0 as! CGFloat
// Calculating which page "card" we should be on
let currentOffset = scrollView.contentOffset.x - cellWidth/2
print("currentOffset is \(currentOffset)")
let cardWidth = cellWidth + cellPadding
var page = Int(round((currentOffset)/(cardWidth) + 1))
print("current page number is: \(page)")
if (velocity.x < 0) {
page -= 1
}
if (velocity.x > 0) {
page += 1
}
print("Updated page number is: \(page)")
print("Previous page number is: \(self.previousPage)")
// Only allowing the user to scroll for one page!
if(page > self.previousPage) {
page = self.previousPage + 1
self.previousPage = page
}
else if (page == self.previousPage) {
page = self.previousPage
}
else {
page = self.previousPage - 1
self.previousPage = page
}
print("new page number is: " + String(page))
print("addedCards.count + 1 is: " + String(addedCards.count + 1))
if (page == addedCards.count) {
print("reloading data")
// Update data source
addedCards.append("card")
// Method 1
cardCollectionView.reloadData()
// Method 2
// let newIndexPath = NSIndexPath(forItem: addedCards.count - 1, inSection: 0)
// cardCollectionView.insertItemsAtIndexPaths([newIndexPath])
}
// print("Centering on new cell")
// Center the cardCollectionView on the new page
let newOffset = CGFloat(page * Int((cellWidth + cellPadding)))
print("newOffset is: \(newOffset)")
targetContentOffset.memory.x = newOffset
}
Although I think I have nearly got the desired result there are still some concerns and also bugs that I have found.
My main concern is the fact that instead of inserting a single cell at the end of myCollectionView I'm reloading the whole table. The reason that I do this is because if I didn't then myCollectionView.contentOffset wouldn't be changed and as a result when a new cell is created, myCollectionView isn't centered on the newly created cell.
1. If the user scrolls very slowly and then stops, the new cell gets created but then myCollectionView gets stuck in between two cells it doesn't center in on the newly created cell.
2. When myCollectionView is in between the second last cell and the last cell as a result of 1., the next time the user swipes right, instead of creating one single cell, two cells are created.
I've also used different ways to implement this behaviour such as using scrollViewDidScroll, and various other but to no avail. Can anyone point me in the right direction as I am kind of lost.
Here is a link to download my project if you want to see the interaction:
My Example Project
These the old methods if you're interested:
To do this I have tried 2 ways,
The first being:
func scrollViewWillEndDragging(scrollView: UIScrollView, withVelocity velocity: CGPoint,
targetContentOffset: UnsafeMutablePointer<CGPoint>) {
// page is the current cell that the user is on
// addedCards is the array that the data source works with
if (page == addedCards.count + 1) {
let placeholderFlashCardProxy = FlashCardProxy(phrase: nil, pronunciation: nil, definition: nil)
addedCards.append(placeholderFlashCardProxy)
let newIndexPath = NSIndexPath(forItem: addedCards.count, inSection: 0)
cardCollectionView.insertItemsAtIndexPaths([newIndexPath])
cardCollectionView.reloadData()
}
}
The problem with using this method is that:
Sometimes I will get a crash as a result of: NSInternalInconsistencyException', reason: 'Invalid update: invalid number of items in section 0.
When a new collectionCell is added it will sometimes display the input that the user has written from the previous cell (this might have sometimes to do with the dequeuing and re-use of cell, although again, I'm not sure and I would be grateful if someone answered it)
The inserting isn't smooth, I want the user to be able to swipe left at the last cell and "into" a new cell. As in if I am currently on the last cell, swiping left would put me automatically at the new cell, because right now when I swipe left a new cell is created by it doesn't center on the newly created cell
The second method that I am using is:
let swipeLeftGestureRecognizer = UISwipeGestureRecognizer(target: self, action: "swipedLeftOnCell:")
swipeLeftGestureRecognizer.direction = .Left
myCollectionView.addGestureRecognizer(swipeLeftGestureRecognizer)
swipeLeftGestureRecognizer.delegate = self
Although the swipe gesture very rarely responds, but if I use a tap gesture, myCollectionView always responds which is very weird (I know again this is a question on its own)
My question is which is the better way to implement what I have described above? And if none are good what should I work with to create the desired results, I've been trying to do this for two days now and I was wondering if someone could point me in the right direction. Thanks!
I hope this helps out in some way :)
UPDATE
I updated the code to fix the issue scrolling in either direction.
The updated gist can be found here
New Updated Gist
Old Gist
First I'm gonna define some model to for a Card
class Card {
var someCardData : String?
}
Next, create a collection view cell, with a card view inside that we will apply the transform to
class CollectionViewCell : UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: frame)
self.addSubview(cardView)
self.addSubview(cardlabel)
}
override func prepareForReuse() {
super.prepareForReuse()
cardView.alpha = 1.0
cardView.layer.transform = CATransform3DIdentity
}
override func layoutSubviews() {
super.layoutSubviews()
cardView.frame = CGRectMake(contentPadding,
contentPadding,
contentView.bounds.width - (contentPadding * 2.0),
contentView.bounds.height - (contentPadding * 2.0))
cardlabel.frame = cardView.frame
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
lazy var cardView : UIView = {
[unowned self] in
var view = UIView(frame: CGRectZero)
view.backgroundColor = UIColor.whiteColor()
return view
}()
lazy var cardlabel : UILabel = {
[unowned self] in
var label = UILabel(frame: CGRectZero)
label.backgroundColor = UIColor.whiteColor()
label.textAlignment = .Center
return label
}()
}
Next setup the view controller with a collection view. As you will see there is a CustomCollectionView class, which I will define near the end.
class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {
var cards = [Card(), Card()]
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(collectionView)
collectionView.frame = CGRectMake(0, 0, self.view.bounds.width, tableViewHeight)
collectionView.contentInset = UIEdgeInsetsMake(0, 0, 0, contentPadding)
}
lazy var collectionView : CollectionView = {
[unowned self] in
// MARK: Custom Flow Layout defined below
var layout = CustomCollectionViewFlowLayout()
layout.contentDelegate = self
var collectionView = CollectionView(frame: CGRectZero, collectionViewLayout : layout)
collectionView.clipsToBounds = true
collectionView.showsVerticalScrollIndicator = false
collectionView.registerClass(CollectionViewCell.self, forCellWithReuseIdentifier: "CollectionViewCell")
collectionView.delegate = self
collectionView.dataSource = self
return collectionView
}()
// MARK: UICollectionViewDelegate, UICollectionViewDataSource
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return cards.count
}
func collectionView(collectionView : UICollectionView, layout collectionViewLayout:UICollectionViewLayout, sizeForItemAtIndexPath indexPath:NSIndexPath) -> CGSize {
return CGSizeMake(collectionView.bounds.width, tableViewHeight)
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cellIdentifier = "CollectionViewCell"
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellIdentifier, forIndexPath: indexPath) as! CollectionViewCell
cell.contentView.backgroundColor = UIColor.blueColor()
// UPDATE If the cell is not the initial index, and is equal the to animating index
// Prepare it's initial state
if flowLayout.animatingIndex == indexPath.row && indexPath.row != 0{
cell.cardView.alpha = 0.0
cell.cardView.layer.transform = CATransform3DScale(CATransform3DIdentity, 0.0, 0.0, 0.0)
}
return cell
}
}
UPDATED - Now For the really tricky part. I'm gonna define the CustomCollectionViewFlowLayout. The protocol callback returns the next insert index calculated by the flow layout
protocol CollectionViewFlowLayoutDelegate : class {
func flowLayout(flowLayout : CustomCollectionViewFlowLayout, insertIndex index : NSIndexPath)
}
/**
* Custom FlowLayout
* Tracks the currently visible index and updates the proposed content offset
*/
class CustomCollectionViewFlowLayout: UICollectionViewFlowLayout {
weak var contentDelegate: CollectionViewFlowLayoutDelegate?
// Tracks the card to be animated
// TODO: - Adjusted if cards are deleted by one if cards are deleted
private var animatingIndex : Int = 0
// Tracks thje currently visible index
private var visibleIndex : Int = 0 {
didSet {
if visibleIndex > oldValue {
if visibleIndex > animatingIndex {
// Only increment the animating index forward
animatingIndex = visibleIndex
}
if visibleIndex + 1 > self.collectionView!.numberOfItemsInSection(0) - 1 {
let currentEntryIndex = NSIndexPath(forRow: visibleIndex + 1, inSection: 0)
contentDelegate?.flowLayout(self, insertIndex: currentEntryIndex)
}
} else if visibleIndex < oldValue && animatingIndex == oldValue {
// if we start panning to the left, and the animating index is the old value
// let set the animating index to the last card.
animatingIndex = oldValue + 1
}
}
}
override init() {
super.init()
self.minimumInteritemSpacing = 0.0
self.minimumLineSpacing = 0.0
self.scrollDirection = .Horizontal
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
// The width offset threshold percentage from 0 - 1
let thresholdOffsetPrecentage : CGFloat = 0.5
// This is the flick velocity threshold
let velocityThreshold : CGFloat = 0.4
override func targetContentOffsetForProposedContentOffset(proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint {
let leftThreshold = CGFloat(collectionView!.bounds.size.width) * ((CGFloat(visibleIndex) - 0.5))
let rightThreshold = CGFloat(collectionView!.bounds.size.width) * ((CGFloat(visibleIndex) + 0.5))
let currentHorizontalOffset = collectionView!.contentOffset.x
// If you either traverse far enought in either direction,
// or flicked the scrollview over the horizontal velocity in either direction,
// adjust the visible index accordingly
if currentHorizontalOffset < leftThreshold || velocity.x < -velocityThreshold {
visibleIndex = max(0 , (visibleIndex - 1))
} else if currentHorizontalOffset > rightThreshold || velocity.x > velocityThreshold {
visibleIndex += 1
}
var _proposedContentOffset = proposedContentOffset
_proposedContentOffset.x = CGFloat(collectionView!.bounds.width) * CGFloat(visibleIndex)
return _proposedContentOffset
}
}
And define the delegate methods in your view controller to insert a new card when the delegate tell it that it needs a new index
extension ViewController : CollectionViewFlowLayoutDelegate {
func flowLayout(flowLayout : CustomCollectionViewFlowLayout, insertIndex index : NSIndexPath) {
cards.append(Card())
collectionView.performBatchUpdates({
self.collectionView.insertItemsAtIndexPaths([index])
}) { (complete) in
}
}
And below is the custom Collection view that applies the animation while scrolling accordingly :)
class CollectionView : UICollectionView {
override var contentOffset: CGPoint {
didSet {
if self.tracking {
// When you are tracking the CustomCollectionViewFlowLayout does not update it's visible index until you let go
// So you should be adjusting the second to last cell on the screen
self.adjustTransitionForOffset(NSIndexPath(forRow: self.numberOfItemsInSection(0) - 1, inSection: 0))
} else {
// Once the CollectionView is not tracking, the CustomCollectionViewFlowLayout calls
// targetContentOffsetForProposedContentOffset(_:withScrollingVelocity:), and updates the visible index
// by adding 1, thus we need to continue the trasition on the second the last cell
self.adjustTransitionForOffset(NSIndexPath(forRow: self.numberOfItemsInSection(0) - 2, inSection: 0))
}
}
}
/**
This method applies the transform accordingly to the cell at a specified index
- parameter atIndex: index of the cell to adjust
*/
func adjustTransitionForOffset(atIndex : NSIndexPath) {
if let lastCell = self.cellForItemAtIndexPath(atIndex) as? CollectionViewCell {
let progress = 1.0 - (lastCell.frame.minX - self.contentOffset.x) / lastCell.frame.width
lastCell.cardView.alpha = progress
lastCell.cardView.layer.transform = CATransform3DScale(CATransform3DIdentity, progress, progress, 0.0)
}
}
}
I think u missed one point here in
let newIndexPath = NSIndexPath(forItem: addedCards.count, inSection: 0)
the indexPath should be
NSIndexPath(forItem : addedCards.count - 1, inSection : 0) not addedCards.count
Thats why you were getting the error
NSInternalInconsistencyException', reason: 'Invalid update: invalid number of items in section 0

How to drag a static cell into tableView swift?

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

Programmatically created UITableView with non self datasource & delegates

I'd like to use an instance of a separate class as my UITableView's datasource & delegate. I create a new instance of the class that should handle this role and assign it via my tableview's properties:
autoMakesTable is defined as property:
var autoMakesTable : UITableView?
Further down:
func nextBttnTouched(sender: AnyObject) {
switch self.autoState {
case .NewOrEdit:
self.autoState = .YearEntered
// If the picker wasn't used create a new Auto with the default year value
self.auto = Auto(year: NSNumber(integerLiteral: self.yearPickerValues.count - 2), make: "", model: "", body: "", trim: "", downPaymentBudget: 0, monthlyPaymentBudget: 0)
// Prepare the make & model fields
backgroundFieldView = UIView(frame: CGRectMake(0, 0-self.view.frame.size.height/2, self.view.frame.width, self.view.frame.height/2))
backgroundFieldView!.backgroundColor = UIColor(red: 251/255, green: 251/255, blue: 251/255, alpha: 1.0)
let makeField = UITextField(frame: CGRectMake(self.view.center.x - 100, self.navigationController!.navigationBar.frame.size.height + 34, 200, 30))
makeField.delegate = self
makeField.placeholder = "Make"
makeField.addTarget(self, action: Selector("makeTextChanged:"), forControlEvents: UIControlEvents.EditingChanged)
let modelField = UITextField(frame: CGRectMake(self.view.center.x - 100, makeField.frame.origin.y + makeField.frame.size.height + 8, 200, 30))
modelField.placeholder = "Model"
let newAutoMakesTableData = AutoMakesTableData()
autoMakesTable = UITableView(frame: CGRectMake(makeField.frame.origin.x, makeField.frame.origin.y + makeField.frame.height + 2, makeField.frame.width, 100))
autoMakesTable!.dataSource = newAutoMakesTableData
autoMakesTable!.delegate = newAutoMakesTableData
self.backgroundFieldView?.addSubview(self.autoMakesTable!)
self.autoMakesTable!.reloadData()
makeField.becomeFirstResponder()
self.addBorderToTextField([makeField,modelField])
self.view.addSubview(backgroundFieldView!)
// Move year picker with animation
// Update next button location while loading make / model input fields with animation
UIView.animateWithDuration(0.8, animations: { () -> Void in
self.newYearPicker?.frame.origin.y = 0
self.backgroundFieldView!.frame.origin.y = 0
self.backgroundFieldView!.addSubview(makeField)
self.backgroundFieldView?.addSubview(modelField)
//self.backgroundFieldView?.addSubview(self.autoMakesTable!)
// self.autoMakesTable!.reloadData()
})
case .YearEntered:
self.autoState = .MakeModelEntered
case .MakeModelEntered:
self.autoState = .DetailsEntered
case .DetailsEntered:
self.autoState = .BudgetEntered
case .BudgetEntered:
performSegueWithIdentifier("next", sender: self)
}
}
It's added onto the view hierarchy (I intact see an empty tableview with a few rows) later on. I also try to call reloadData() on it to no effect.
AutoMakesTableData is defined like so:
import UIKit
class AutoMakesTableData: NSObject, UITableViewDataSource, UITableViewDelegate {
// Auto makes URL
// This should be hosted online so changes can be made w/out having to re-submit the app
let urlForMakes = NSBundle.mainBundle().URLForResource("makes", withExtension: "JSON")
var autoMakes : [String]?
override init() {
super.init()
self.populateAutoMakesFromURL(urlForMakes!)
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let aCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
print("cell created")
return aCell
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
print("selected row")
}
private func populateAutoMakesFromURL(url: NSURL) {
do {
let jsonAutoMakesData = try NSData(contentsOfURL: url, options: NSDataReadingOptions.DataReadingMappedIfSafe)
do {
let jsonAutoMakes = try NSJSONSerialization.JSONObjectWithData(jsonAutoMakesData, options: NSJSONReadingOptions.MutableContainers) as! [String:[String]]
self.autoMakes = jsonAutoMakes["makes"]
// Sort array alphabetically
self.autoMakes?.sortInPlace(<)
} catch let error as NSError {
print(error.userInfo.debugDescription)
}
} catch let error as NSError {
print(error.userInfo.debugDescription)
}
}
}
I can access the autoMakes array property on this instance without a problem.
The table view shows up but none of the print statements fire (for a cell at index path or for did select row).
I don't see anywhere where you install the table view into the view hierarchy. If you don't install the view controller into the active view hierarchy it won't do anything.
That is my guess as to what's going wrong.
It's ok to have a separate object serve as the data source/delegate of the view controller.
EDIT:
Based on discussion below this answer, it turns out the problem was that the OP was creating his AutoMakesTableData in a method and assigning it to a local variable but not saving any other strong references to it.
When the method that created the AutoMakesTableData object returned, the local variable went out of scope, there were no more strong references to the object, and it was deallocated.
A table view's delegate and dataSource properties are weak, so those get zeroed out when the object is deallocated. The table view no longer has a data source, so nothing happens.

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