I have a UICollectionView and i want to save the data (images) always in the first cell and the old data walks to the next cells. So when i save a new photo it´s comes in the first cell, i have tried with indexpath.row == 0 {} in cellForRowAtIndexPath but he saves only in the first cell in the other cells are nothing. Can i invert the save index or give it a another way ??
So have anyone a idea what i can make there ??
override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return picture.count
}
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("BookPicCell", forIndexPath: indexPath) as! BookPicCell
let cellcore = picture[indexPath.row]
if indexPath.row == 0 {
cell.BookImage.image = UIImage(contentsOfFile: cellcore.foto!)
}
return cell
}
Thanks for your Help.
You need to create an array of UIImages and append the new image to the front of that array:
pictures.insert(newImage, atIndex : 0)
Than after you inserted your new image you need to reload your UICollectionView using:
self.collectionView.reloadData()
You do not want to sort your data inside the cellForItemAtIndexPath
Related
I have a ViewController that have a collectionView and I managed to make it selectable and all but the problem is that I have a checkmark image that stays in the first cell when the VC opens but in fact the cell is not selected at all and still the checkmark is there!
Code of the VC:
var selected = IndexPath(item: 0, section: 0)
var properties = connectedProperties(StatusCode: 0)
var propertiesNew = connectedProperties(StatusCode: 0)
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return properties.Result?.count ?? 0
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "dashboardCollectionViewCell", for: indexPath) as? dashboardCollectionViewCell else { return UICollectionViewCell() }
let currentPropertie = properties.Result?[indexPath.row]
cell.checkMarkButton.isHidden = !(indexPath == selected)
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let selectedCell = properties.Result?[indexPath.row]
changeCustomerKey.DefaultsKeys.keyTwo = indexPath.row
changeCustomerKey.DefaultsKeys.keyThree = selectedCell!.id!
let previous = selected.dropLast()
selected = indexPath
collectionView.reloadItems(at: [previous, selected])
}
If you want to tell your collection view to select a specific cell, you need to call the UICollectionView method selectItem(at:animated:scrollPosition:).
The "tricky bit" is that you can't call that until the collection view has finished populating itself (by calling your data source methods) and the first cell has been added to the collection view.
You might need to resort to something a bit hacky like adding an "initialDisplay" bool property who's value starts as true.
In your data source method that returns cells, check if initialDisplay==true and the requested indexPath is (0,0). If so, set initialDisplay=false, and fire a one-shot timer with a short delay. In the timer's closure, call selectItem(at:animated:scrollPosition:). The timer delay will return control to the event loop and give the system time to add the cell to the collection view.
There might be a better way to do this, but I can't think of it offhand, since you can't be sure when you will be asked to return your cell at IndexPath (0,0)
I have a collection view that is being populated with images created from parsed data. It is being populated and updated by using an NSFetchedResultsController as the data source. The code is in Swift 4, so to do so I am using the data source methods for the collection view along with the delegate methods for the NSFetchedResultsControllerDelegate as shown here:
func collectionView (_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if let count = fetchedResultsController.sections?[0].numberOfObjects {
return count
}else {
return 0
}
}
func collectionView (_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
print("Setting cell with photo")
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "photoCell", for: indexPath) as! CollectionViewCell
let photoForCell = fetchedResultsController.object(at: indexPath)
cell.cellImage.image = UIImage(data: photoForCell.imageData!)
print(photoForCell.imageData!)
return cell
}
I am trying to calculate how many images were pulled in the parsed data and use this information to temporarily populate that many cells in the collection view with the same placeholder image in all of them. Then, once the images have all been downloaded and saved the NSFetchedResultsController will trigger the data source methods to refresh and populate the collection view with the new photos instead of the placeholder photos.
I have not been able to find any videos or posts that show how to do so. I tried creating a variable that holds the count of objects in the parsed data. That variable is then used in an if statement in the (:numberOfItemsInSection:) and (:cellForItemAt:) to determine whether it should populate the collection from saved photos or using the temporary photos like this:
func collectionView (_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if self.placeHolderCount != nil {
return placeHolderCount
}
if let count = fetchedResultsController.sections?[0].numberOfObjects {
return count
}else {
return 0
}
}
func collectionView (_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
print("Setting cell with photo")
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "photoCell", for: indexPath) as! CollectionViewCell
let photoForCell = fetchedResultsController.object(at: indexPath)
if self.placeHolderCount != nil {
cell.cellImage.image = #imageLiteral(resourceName: "VirtualTourist_5112")
return cell
}
cell.cellImage.image = UIImage(data: photoForCell.imageData!)
print(photoForCell.imageData!)
return cell
}
Unfortunately, that causes the app to crash with an error saying "NSInvalidArgumentException reason: 'no object at index 0 in section at index 0"
During my troubleshooting, I found that this crash happens at the point when the view context is saved after downloading all the images. Everything in the application works perfectly including loading the downloaded images until I add the changes to the delegate methods. Does anyone know if I am on the right track? Should I be going about it in a completely different way? I have seen external libraries around that will accomplish this, but I cannot use any external libraries or frameworks for this particular application.
I want to dynamically add collection view inside tableview. I have make following code.
A cell class for collectionview
class NewsFeedCollectionViewCell : UICollectionViewCell{
#IBOutlet weak var imageViewSlider: UIImageView!
}
Than assign collectionview in Tableview cellforrow at indexpath
cell.collectionViewNewsFeed.tag = indexPath.row
cell.collectionViewNewsFeed.reloadData()
Than added following delegates of collectionview
// MARK: - Collection view Delegates / Datasources
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return (mutableArrayNewsFeed[collectionView.tag]["images"] as! NSArray).count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("NewsFeedCollectionViewCell", forIndexPath: indexPath) as! NewsFeedCollectionViewCell
print("tag : \(collectionView.tag) , Row : \(indexPath.row)")
let img = (mutableArrayNewsFeed[collectionView.tag]["images"] as! NSArray)[indexPath.row] as? String ?? "imgLoginScreenLogo"
cell.imageViewSlider.image = UIImage(named: img)
return cell
}
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
print("Collection View Row : \(indexPath.row)")
}
func collectionView(collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize{
return collectionView.frame.size
}
Its adjusting properly but the indexes gets changes while i scroll the collectionview. For ex, I scroll collectionview upto 3 cell than i go to the tableview 4th index than it also set the index of 4th index of collectionview to 3rd.
Simply want to add collection view with multiple images inside Table view. I have added, but after scrolling the collection view to 3rd image on 1st cell of tableview, i move to 4th cell of Tableview, there also the collectionview gets scrolled automatically upto 4th cell.
Need to get out of this.
There was an issue with the indexpath, I get the solution by keeping the indexpath in an array.
Refer Following link
https://github.com/ashfurrow/Collection-View-in-a-Table-View-Cell
So I have a collectionView in a viewcontroller. I have a variable var user = User! which stores the current selected user (FYI I'm using Parse). I want to pass variable to the custom cell.
extension SentViewController : UICollectionViewDataSource
{
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int
{
return 1
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
return cards.count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
{
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(Storyboard.CellIdentifier, forIndexPath: indexPath) as! SentCardCollectionViewCell
cell.card = self.cards[indexPath.item]
cell.delegate = self
cell.user = user
return cell
}
}
Now, my problem is that when I pass the variable user to the variable user in custom collection view cell, I get an object that repeats 3 times. i.e.: the same variable gets passed over, but it is multiplied 3 times.
Any idea how to solve this? I have a feeling that it has something to do with the indexPath. Anyone have solutions?
Hi so I'm using a side scrolling UICollectionView to display groups of people that the user makes. The groups are stored on my server and when the view loads, they load from the server. However I want the first cell to always be the same which is a cell which lets you create groups. This is the layout i need.
I know how to use multiple different custom cells, but how do I make it so the first cell is static and the cells after load content from my servers? Thanks :)
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return familyName.count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
if indexPath.row == 0 {
let cell : AddGroupCollectionViewCell = collectionViewOutlet.dequeueReusableCellWithReuseIdentifier("Add", forIndexPath: indexPath) as! AddGroupCollectionViewCell
return cell
} else {
let cell : FriendGroupsCell = collectionViewOutlet.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! FriendGroupsCell
cell.groupImage.image = UIImage(named: "pp")
cell.groupNameLabel.text = familyName[indexPath.row]
return cell
}
}
This is my code and it misses out the first person in the array because the index path skips over it. How can i modify this so it works
UICollectionViewCell is leveraging reusing techniques to improve performance. Remember this. Nothing can be static in a cell, because this cell later will be on another index.
You can use collectionView:cellForItemAtIndexPath: to make the first cell always load the same images/labels via indexPath.row == 0
You can use prepareReuse method to clean up the resources in the cell. So if cell No.2 is going to be the new No.1 cell, it get a chance to clean up old resources.
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell : AddGroupCollectionViewCell = collectionViewOutlet.dequeueReusableCellWithReuseIdentifier("Add", forIndexPath: indexPath) as! AddGroupCollectionViewCell
if indexPath.row == 0 {
cell.groupImage.image = UIImage(named: "new")
cell.groupNameLabel.text = "new"
} else {
cell.groupImage.image = UIImage(named: "pp")
cell.groupNameLabel.text = familyName[indexPath.row]
}
return cell
}