I have a collection view, but cell that are not appearing in the screen i cannot access, 1...5 ok, and those at index parth row 6, 7, and they have to be scrolled to bee seen
func Action0(sender: UIButton!) {
for i in 0...7 {
if i != 0{
var indexPath = NSIndexPath(forRow: i, inSection: 0)
var cell = collectionView!.cellForItemAtIndexPath(indexPath)
cell!.backgroundColor = UIColor.whiteColor()
}else{
var indexPath = NSIndexPath(forRow: 0, inSection: 0)
var cell = collectionView!.cellForItemAtIndexPath(indexPath)
cell!.backgroundColor = UIColor.blueColor()
}
}
}
How to acces those cells that are not yet visible?
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as! CollectionViewCell
cell.backgroundColor = UIColor.blackColor()
cell.textLabel.text = "\(indexPath.section):\(indexPath.row)"
cell.buttonView.setBackgroundImage(UIImage(named: "Good"), forState: UIControlState.Normal)
cell.buttonView.addTarget(self, action: Selector("Action\(indexPath.row):"), forControlEvents: UIControlEvents.TouchUpInside)
return cell
}
Cells that are not yet visible do not exist. Table views and collection views only create just the cells that are currently visible. When you scroll, the cells that go out of view get recycled and reused for the new index path(s) that come into view.
You need to think in terms of your data model, which holds the data for each index path, and cells, which display a view of of subset of some of that data.
Related
I added buttons in my collection view cells by the code below, where 'myButton' refers to the buttons I try to make access to.
When I click some button outside the collectionView, I want one of my buttons to have its background image changed to have the background of the button clicked, which I tried with 'sendToBox' function below;
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! ItemCollectionViewCell
cell.myButton.setTitle(self.items[indexPath.item], for: .normal)
cell.backgroundColor = UIColor.white
cell.layer.borderColor = UIColor.black.cgColor
cell.layer.borderWidth = 0.5
return cell
}
...
#IBAction func keyClick(_ sender: UIButton) {
...
sendToBox(object: sender)
...
}
...
func sendToBox(object sentObject: UIButton) {
let imageToSend = sentObject.backgroundImage(for: .normal)
let imageIdentity = sentObject.restorationIdentifier
let cell = self.collectionView(ItemCollectionSet, cellForItemAt: IndexPath(item: 0, section: 0))
cell.myButton ## blah blah not working!
}
So I want to make a direct access to one of the cells I created, and then change the button inside it to have a different appearance. I'm stuck in this matter for a whole day, please help me out.
So the issue is when a cell is tapped, desired data is shown and when again tapped on same cell ( again desired data is shown.)
But when one cell is selected and we again select other cell (then the data is been shown of second tapped cell but the first one is not deselected).
How can I take care of this issue?
var selectedIndex = -1
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
UIView.animate(withDuration: 1) {
self.labelViewHeightConstraint.constant = 60
self.labelLeadingConstraint.constant = 136
self.view.layoutIfNeeded()
}
let cell = tableView.cellForRow(at: indexPath) as! CustomCell
if(selectedIndex == indexPath.row) {
selectedIndex = -1
print("deselect")
UIView.animate(withDuration: 0.4) {
cell.secondView.isHidden = true
cell.firstView.backgroundColor = UIColor(red: 0.8588, green: 0.84705, blue: 0.8745, alpha: 1.0)
}
} else {
cell.secondView.isHidden = false
}
self.expandTableView.beginUpdates()
//self.expandTableView.reloadRows(at: [indexPath], with: UITableViewRowAnimation.automatic )
self.expandTableView.endUpdates()
}
You can archive single selection by setting tableView property like belwo
tableView.allowsMultipleSelection = false
This can also be done from Attributes Inspector
Hope this helps
you must disable multiple selection by,
self.tbl.allowsMultipleSelection = false
and enable single selection by,
self.tbl.allowsSelection = true
EDIT:-
if you want to access your old (selected cells), you should make a call like this,
//first assign tag or indexPath in Cell,
cell.tag = indexPath.row
// or
cell.indexPath = indexPath
//then fetch like bellow,
let visibleCell = tableView.visibleCells.filter({$0.tag == self.selectedIndex})
//or
let visibleCell = tableView.visibleCells.filter({$0.indexPath.row == self.selectedIndex})
//if you use ,
let cell = tableView.cellForRow(at: indexPath) as! CustomCell
//then it will get you new cell object.
What I want to ask you is "Can one UITableviewcell be used for multiple tableview like viewholder that can use anytime for recyclerview in android?" what I used to do is in one viewcontroller I have a tableview with a custom Cell and gave its identifier as normal but if I trying to use another uitableview in another Viewcontroller with that cell that inside the previous tableview, it always gives me a blank cell with white background. is there a way to use it like that?
EDIT: Here is what my tableview look like when i've already set cellforrow for it already.
Click to view and here what my cell look like Click to view cell and here are my code for different cell in a tableview, It'll work if i use use those 2 cell in current tableview
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0{
let cell = self.mytable.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! HistoryItemTableCell
let view = UIView(frame: CGRect(x: 0, y: cell.frame.maxY, width: cell.frame.size.width, height: cell.frame.size.height))
view.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.3)
cell.selectedBackgroundView = view
let order = OrderItemObj
cell.num_of_day.text = "\(order.ticket_type.name)"
cell.ref_num.text = order.order_tx_number
cell.quantity.text = order.number_tickets
cell.price.text = "$\(order.ticket_type.price).00 USD"
if order.status == "unpaid"{
cell.ic_status.image = UIImage(named: "ic_status_unpaid")
}else{
cell.ic_status.image = UIImage(named: "ic_status_paid")
}
cell.start_date.text = "\(order.start_date)"
cell.end_date.text = "\(order.expired_date)"
return cell
}else{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! OrderDetailTicketCell
let t = listTicket[indexPath.row]
cell.dob.text = t.dob
cell.gender.text = t.sex
cell.nation.text = t.nationality
let url = URL(string: t.photo)
cell.imageN.kf.setImage(with: url)
return cell
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if section == 0 {
return 3
}else{
return self.listTicket.count
}
}
override func viewDidLoad(){
super.viewDidLoad()
mytable.register(HistoryItemTableCell.self, forCellReuseIdentifier: "cell")
ViewHistoryItem()
mytable.dataSource = self
mytable.delegate = self
}
Yes you can. You have to register it again for the new tableView. It is just like how you create variables using the same type. This is also a class which can be used to create objects. Doesn't matter where you want to use it.
On the other hand if you are asking if instances of the same cell which are present in a tableView can be reused in another tableView, then the answer is no, because they have only been registered for that particular tableView.
I've seen everywhere that it's bad practice to iterate through a tableView but I'm afraid I have no other alternative. I want to have the AVSpeechSynthesizer read the content of the labels that are inside my custom UITableViewCells.
Of course, this could be done directly using the source array of the tableView but the problem is that I want to have the synthesiser read the labels and at the same time highlight the words that are being spoken.
I have done some tests but the problem is that as the cells are being reused by the table view, I end up with empty cells...
What is the right way of ensuring my cells are not empty ?
I've tried scrolling the tableView to ensure the cells aren't empty but it doesn't work either.
Here is my code so far ...
func scrollToRow(rowToGo: Int) {
self.collectionView.scrollToItem(at: self.indexPath as IndexPath, at: .centeredVertically, animated: true)
let colorCell = self.collectionView.dequeueReusableCell(withReuseIdentifier: "ColorCell", for:indexPath as IndexPath ) as! ColorCell
let myString = colorCell.colorLabel.text!
print(myString)
self.speakString(sender: self, str:(myString))
}
#IBAction func playPauseButton(_ sender: UIButton) {
if !self.speechSynthesizer.isSpeaking{
let btnImage = UIImage(named: "pausedButton.png")
self.playPauseButton.setImage(btnImage , for: UIControlState.normal)
self.isPaused = false
// var indexPath:Double = 0
self.indexPath = NSIndexPath(row: 0, section: 0)
for i in 0...36 {
print(i)
self.indexPath = NSIndexPath(row: i, section:0)
self.scrollToRow(rowToGo:i)
// self.indexPath = NSIndexPath(index:i)
// self.collectionView.selectItem(at: indexPath as IndexPath, animated: true, scrollPosition: .centeredVertically)
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt
indexPath: IndexPath) -> UICollectionViewCell {
let myCell = collectionView.dequeueReusableCell(withReuseIdentifier:
"ColorCell", for: indexPath) as! ColorCell
myCell.colorLabel.text = self.wordList[indexPath.row]
myCell.colorImage.image = self.images[indexPath.row]
return myCell }
My collectionView is displayed correctly and all my labels inside the UICollectionViewCells contain text. However, when I press the play button, the first time, nothing gets spoken. If I scroll back and press again, only 3 or 4 cells actually exist and get their label.text printed and spoken while all the other indexes are empty.
Any suggestion would be welcome
Here's a problem which I have been stuck at for quite some time now.
Here's the code
let indexPath = NSIndexPath(forRow: sender.tag, inSection: 0)
collectionViewLove?.performBatchUpdates({() -> Void in
self.collectionViewLove?.deleteItemsAtIndexPaths([indexPath])
self.wishlist?.results.removeAtIndex(indexPath.row)
self.collectionViewLove?.reloadData()}, completion: nil)}
I have a button inside each UICollectionViewCell which deletes it on clicking. The only way for me to retrieve the indexPath is through the button tag. I have initialized the button tag in
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
However every time I delete, the first time it deletes the corresponding cell whereas the next time it deletes the cell follwing the one I clicked. The reason is that my button tag is not getting updated when I call the function reloadData().
Ideally, when I call the reloadData() ,
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
should get called and update the button tag for each cell. But that is not happening. Solution anyone?
EDIT:
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
collectionView.registerNib(UINib(nibName: "LoveListCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "Cell")
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! LoveListCollectionViewCell
cell.imgView.hnk_setImageFromURL(NSURL(string: (wishlist?.results[indexPath.row].image)!)!, placeholder: UIImage(named: "preloader"))
let item = self.wishlist?.results[indexPath.row]
cell.layer.borderColor = UIColor.grayColor().CGColor
cell.layer.borderWidth = 1
cell.itemName.text = item?.title
cell.itemName.numberOfLines = 1
if(item?.price != nil){
cell.price.text = "\u{20B9} " + (item?.price.stringByReplacingOccurrencesOfString("Rs.", withString: ""))!
}
cell.price.adjustsFontSizeToFitWidth = true
cell.deleteButton.tag = indexPath.row
cell.deleteButton.addTarget(self, action: "removeFromLoveList:", forControlEvents: .TouchUpInside)
cell.buyButton.tag = indexPath.row
cell.buyButton.backgroundColor = UIColor.blackColor()
cell.buyButton.addTarget(self, action: "buyAction:", forControlEvents: .TouchUpInside)
return cell
}
A couple of things:
You're doing too much work in cellForItemAtIndexPath--you really want that to be as speedy as possible. For example, you only need to register the nib once for the collectionView--viewDidLoad() is a good place for that. Also, you should set initial state of the cell in the cell's prepareForReuse() method, and then only use cellForItemAtIndexPath to update with the custom state from the item.
You shouldn't reload the data until the deletion is complete. Move reloadData into your completion block so the delete method is complete and the view has had time to update its indexes.
However, it would be better if you didn't have to call reloadData in the first place. Your implementation ties the button's tag to an indexPath, but these mutate at different times. What about tying the button's tag to, say, the wishlist item ID. Then you can look up the appropriate indexPath based on the ID.
Revised code would look something like this (untested and not syntax-checked):
// In LoveListCollectionViewCell
override func prepareForReuse() {
// You could also set these in the cell's initializer if they're not going to change
cell.layer.borderColor = UIColor.grayColor().CGColor
cell.layer.borderWidth = 1
cell.itemName.numberOfLines = 1
cell.price.adjustsFontSizeToFitWidth = true
cell.buyButton.backgroundColor = UIColor.blackColor()
}
// In your UICollectionView class
// Cache placeholder image since it doesn't change
private let placeholderImage = UIImage(named: "preloader")
override func viewDidLoad() {
super.viewDidLoad()
collectionView.registerNib(UINib(nibName: "LoveListCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "Cell")
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! LoveListCollectionViewCell
cell.imgView.hnk_setImageFromURL(NSURL(string: (wishlist?.results[indexPath.row].image)!)!, placeholder: placeholderImage)
let item = self.wishlist?.results[indexPath.row]
cell.itemName.text = item?.title
if(item?.price != nil){
cell.price.text = "\u{20B9} " + (item?.price.stringByReplacingOccurrencesOfString("Rs.", withString: ""))!
}
cell.deleteButton.tag = item?.id
cell.deleteButton.addTarget(self, action: "removeFromLoveList:", forControlEvents: .TouchUpInside)
cell.buyButton.tag = item?.id
cell.buyButton.addTarget(self, action: "buyAction:", forControlEvents: .TouchUpInside)
return cell
}
func removeFromLoveList(sender: AnyObject?) {
let id = sender.tag
let index = wishlist?.results.indexOf { $0.id == id }
let indexPath = NSIndexPath(forRow: index, inSection: 0)
collectionViewLove?.deleteItemsAtIndexPaths([indexPath])
wishlist?.results.removeAtIndex(index)
}
It's probably not a good idea to be storing data in the cell unless it is needed to display the cell. Instead your could rely on the UICollectionView to give you the correct indexPath then use that for the deleting from your data source and updating the collectionview.
To do this use a delegate pattern with cells.
1.Define a protocol that your controller/datasource should conform to.
protocol DeleteButtonProtocol {
func deleteButtonTappedFromCell(cell: UICollectionViewCell) -> Void
}
2.Add a delegate property to your custom cell which would call back to the controller on the delete action. The important thing is to pass the cell in to that call as self.
class CustomCell: UICollectionViewCell {
var deleteButtonDelegate: DeleteButtonProtocol!
// Other cell configuration
func buttonTapped(sender: UIButton){
self.deleteButtonDelegate.deleteButtonTappedFromCell(self)
}
}
3.Then back in the controller implement the protocol function to handle the delete action. Here you could get the indexPath for the item from the collectionView which could be used to delete the data and remove the cell from the collectionView.
class CollectionViewController: UICollectionViewController, DeleteButtonProtocol {
// Other CollectionView Stuff
func deleteButtonTappedFromCell(cell: UICollectionViewCell) {
let deleteIndexPath = self.collectionView!.indexPathForCell(cell)!
self.wishList.removeAtIndex(deleteIndexPath.row)
self.collectionView?.performBatchUpdates({ () -> Void in
self.collectionView?.deleteItemsAtIndexPaths([deleteIndexPath])
}, completion: nil)
}
}
4.Make sure you set the delegate for the cell when configuring it so the delegate calls back to somewhere.
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
//Other cell configuring here
var cell = collectionView.dequeueReusableCellWithReuseIdentifier("identifier", forIndexPath: indexPath)
(cell as! CustomCell).deleteButtonDelegate = self
return cell
}
}
I was facing the similar issue and I found the answer by just reloading collection view in the completion block.
Just update your code like.
let indexPath = NSIndexPath(forRow: sender.tag, inSection: 0)
collectionViewLove?.performBatchUpdates({
self.collectionViewLove?.deleteItemsAtIndexPaths([indexPath])
self.wishlist?.results.removeAtIndex(indexPath.row)
}, completion: {
self.collectionViewLove?.reloadData()
})
which is mentioned in UICollectionView Performing Updates using performBatchUpdates by Nik