Hi i have an issue in my UICollectionView. First i have a list of images coming from server containing url image.
But when the url is null, the cell is showing random images. I want when the url is null, is just displaying no image.
I'm using SDWebImage for showing the image to UIImageView.
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return listData.count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as! MyCollectionListViewCell
if let url = self.listData[indexPath.row]["photo"] as? String {
let urlPhoto = NSURL(string:url!)
cell.imageView.sd_setImageWithURL(urlPhoto, placeholderImage:img)
cell.imageView.contentMode = UIViewContentMode.ScaleAspectFill
cell.imageView.layer.masksToBounds = true
cell.imageView.clipsToBounds = true
}
}
As UICollectionViewCell will be reused, just set the image to nil for the cell:
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as! MyCollectionListViewCell
if let url = self.listData[indexPath.row]["photo"] as? String {
let urlPhoto = NSURL(string:url!)
cell.imageView.sd_setImageWithURL(urlPhoto, placeholderImage:img)
cell.imageView.contentMode = UIViewContentMode.ScaleAspectFill
cell.imageView.layer.masksToBounds = true
cell.imageView.clipsToBounds = true
} else {
cell.imageView.image = nil
}
}
You can also add this method to your cell class :
override func prepareForReuse() {
self.imageView.image = nil
super.prepareForReuse()
}
Related
I have purposely left an empty image in my assets catalog so that I can get my collectionView to somehow skip that image if it is nil, but so far it will render an empty image in that cell. It is better than crashing my app but how can I get it to skip that image?
here is my cellForItemAt indexPath code. Any ideas would be much appreciated.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: K.collectionViewCell, for: indexPath) as! CollectionViewCell
DispatchQueue.main.async {
let image = RoomModel.roomModel.rooms[indexPath.item]
if let image = image {
cell.imageView.image = image
}
}
return cell
}
Model Solution:
import UIKit
var data = [long list of UIImage(named: ...)]
class RoomModel {
var rooms = data.compactMap { ($0) }
var roomNo = 0
func setRoomNo(sender: Int) {
roomNo = sender
}
func getRoom() -> UIImage {
let image = rooms[roomNo]
return image
}
}
itemForRow Solution:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: K.collectionViewCell, for: indexPath) as! CollectionViewCell
DispatchQueue.main.async {
cell.imageView.image = self.roomModel.rooms[indexPath.item]
}
return cell
}
You would need to modify the data model to not include it if the image is nil and can be done by a simple if check before adding it in the model and then your cell would not render it as it is omitted from the data model.
I have a tableView and collectionView in one view controller.
in tableView I have title description and in collectionView I have lable .
I want on collectionView label selection tableView content should change .
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return Bookmark.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionViewBookmark.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! BookMarkCollectionViewCell
cell.lblTitle.text = Bookmark[indexPath.row]
cell.backgroundColor = UIColor.white
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionViewBookmark.cellForItem(at: indexPath)
cell?.backgroundColor = UIColor.blue
self.selectedIndexPath = indexPath
//
let newsDict = arrNewsData[indexPath.row]
if (indexPath.row == 1)
{
let cell1 = tableViewBookMark.cellForRow(at: indexPath) as! BookMarkFirstTableViewCell
cell1.lblTitle.text = newsDict["title"] as! String
tableViewBookMark.reloadData()
}
tableViewBookMark.reloadData()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableViewBookMark.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! BookMarkFirstTableViewCell
let dict = arrNewsData[indexPath.row]
cell.lblTitle.text = dict["title"] as! String
// cell.imgBookMark.image = dict["image_url"]
let url = URL(string: dict["image_url"] as! String)
URLSession.shared.dataTask(with: url!) { (data, response, error) in
if data != nil{
DispatchQueue.main.async {
let image = UIImage(data: data!)
cell.imgBookMark.image = image
}
}
}.resume()
return cell
}
See my inline comments.
var tempCell: BookMarkFirstTableViewCell?
//Inside cellForRowAt indexPath
tempCell = cell
//Inside (collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
tempCell.lblTitle.text = newsDict["title"] as! String
You're reloading the tableView after updating the values in the cell,
tableViewBookMark.reloadData()
This will trigger the data source function including cellForRowAt, so you will lose your updated values a solution to this is to have a global variable in the UIViewController and check its values inside the cellForRowAt and update it in the collectionView DidSelect .
Extra tip: you don't need to reload all the tableView for a single change you can use
tableView.reloadRows(at: [indexPath], with: .top)
to reload only number of selected cells in the tableView
I using the LJWebImage sample project, Which,I found from github on the following link https://github.com/likumb/LJWebImage. Project,similar to SDWebImage.I am successfully imported the sample project into my project.I am using collectionView to populating the image from plist which contain number of url links.I am trying pass the collectionView selected cellimage to my imageView but no luck so for.please someone point me the direction.my partial collectionView code below.
Thanks in Advance.
let apps: NSArray = AppInfo.appInfo()
#IBOutlet weak var imageView: UIImageView!
#IBOutlet weak var collectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
collectionView!.reloadData()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK: - CollectionView data source
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return apps.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath as IndexPath) as! Cell
cell.app = apps[indexPath.row] as? AppInfo
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if let filePath = Bundle.main.path(forResource: "apps", ofType: "plist"),
let image = UIImage(contentsOfFile: filePath) {
imageView.contentMode = .scaleAspectFit
imageView.image = image
}
}
}
You can retrieve the corresponding app object from the data source array using the indexPath.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
guard let app = apps[indexPath.row] as? AppInfo else { return }
guard let image = UIImage(contentsOfFile: app.filePath) else { return }
imageView.contentMode = .scaleAspectFit
imageView.image = image
}
Or you could retrieve the cell using the indexPath and get the image from it's imageView.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
guard let cell = collectionView.cellForItem(at: indexPath) as? Cell else { return }
imageView.contentMode = .scaleAspectFit
imageView.image = cell.imageView.image
}
I have a UICollectionView of items, and I would like an image in a cell to be toggled when the user selects the cell.
I have a custom UICollectionViewCell:
class RDCell: UICollectionViewCell {
var textLabel: UILabel!
var imageView: UIImageView!
var isSelected: Bool!
...(do init and all that good stuff)
}
And selctected item in collection view :
func collectionView(collectionView: UICollectionView, shouldSelectItemAtIndexPath indexPath: NSIndexPath) -> Bool {
let celld = (collectionView.dequeueReusableCellWithReuseIdentifier("collectionCell", forIndexPath: indexPath) as? RDCell)!
let indexPaths = collectionView.indexPathsForSelectedItems()
let newCell = collectionView.cellForItemAtIndexPath(indexPath) as! RDCell
if(celld.selected){
var image: UIImage = UIImage(named: "notSelected")!
newCell.imageView.image = image
newCell.selected = false
}else{
var image: UIImage = UIImage(named: "selected")!
newCell.imageView.image = image
newCell.selected = true
}
return true
}
My attempt partially works, after selecting and unselecting one item I am not able to select it again after, I need to select a different cell before returning to select the first, and this same bug happens on all selected cells.
Any suggestions or another way to implement the functionality I seek would be greatly appreciated.
Swift 4
I just use the property "highlightedImage" in the "cellForItemAt indexPath" method of the collectionView and set another image on it.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
cell.backgroundColor = UIColor.clear
let imageView = cell.viewWithTag(1) as! UIImageView
imageView.image = imagesArray1[indexPath.row]
imageView.highlightedImage = imagesArray2[indexPath.row]
imageView.contentMode = .scaleAspectFill
return cell
}
In my case, i assigned a tag in the imageView and call it through it.
Best regards.
You should never call cellForItemAtIndexPath directly. You have no guarantee of what cell you're getting and the changes you make may have no effect.
The proper way to do this is to track your state within the class and change the state of the cell in cellForItemAtIndexPath. Then you simply call collectionView?.reloadData() when you need to update the views.
Simple example for reference:
var selectionTracking: [[Bool]] = []
func collectionView(collectionView: UICollectionView, shouldSelectItemAtIndexPath indexPath: NSIndexPath) -> Bool {
if let selected = selectionTracking[indexPath.section][indexPath.row] {
return selected
}
else{
selectionTracking[indexPath.section][indexPath.row] = false
}
return true
}
override func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
if let selected = selectionTracking[indexPath.section][indexPath.row] {
selectionTracking[indexPath.section][indexPath.row] = !selectionTracking[indexPath.section][indexPath.row]
}
else{
selectionTracking[indexPath.section][indexPath.row] = true
}
collectionView?.reloadData()
return true
}
My approach will be different for this, i would have used the didDeselectItemAt method of the collectionView...
Swift 3:
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
let newCell = collectionView.cellForItem(at: indexPath)
newCell.imageView.image = imageAfterSelection[indexPath.row]
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
let newCell = collectionView.cellForItem(at: indexPath)
newCell.imageView.image = imagesAfterDeselection[indexPath.row]
}
Swift 4/5:
Inside your collectionViewCell class define a variable called imageName
then override isSelected property to set the image name based on selected state and in collectionView cellForItemAt method set the value for imageName variable for each cell.
CollectionViewCell Class:
class YourCollectionViewCell: UICollectionViewCell
{
#IBOutlet var cellIcon: UIImageView!
var imageName = ""
override var isSelected: Bool {
didSet {
if self.isSelected {
self.cellIcon.image = UIImage(named: "\(self.imageName) Highlighted")
} else {
self.cellIcon.image = UIImage(named: "\(self.imageName) Unhighlighted")
}
}
}
}
CollectionView DataSource:
class YourCollectionVewController: UICollectionViewDataSource
{
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// this line is an extension don't copy paste
let cell = collectionView.dequeueReusableCell(with: YourCollectionViewCell.self, for: indexPath)
let imageName = "yourImageName Unhighlighted"
cell.cellIcon.image = UIImage(named: imageName)
cell.imageName = imageName
return cell
}
}
I want to Save the First or the Last Image from the UICollectionView and Save it in the UITabelView Cell as UIImage.I try it with the first indexPath if indexPath == 0 catch the UIImage and then save it in CoreData as NSData but it doest works. Have anyone an idea how can i make that or gives another way to Display the UIImage in the UITableViewCell? Thanks for Help.
Here was the code from the UICollectionViewCell:
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("BookPicCell", forIndexPath: indexPath) as! BookPicCell
let cellcore = picture[indexPath.row]
cell.BookImage.image = UIImage(contentsOfFile: cellcore.foto!)
if indexPath.row == 0 {
let firstpic = cell.BookImage.image
let firstcell = UIImagePNGRepresentation(firstpic!)
let firstimag = NSEntityDescription.insertNewObjectForEntityForName("Book", inManagedObjectContext: self.mgdContext) as! Book
firstimag.firstimage = firstcell!
}
do {
try self.mgdContext.save()
} catch {
print("Error")
}
return cell
}
Here was the Code from the UITableViewCell:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let Cell = BookTableView.dequeueReusableCellWithIdentifier("BookCell", forIndexPath: indexPath) as! BookCell
let books = book[indexPath.row]
Cell.BookTitle.text = books.title
let picturecount = books.picture!.count
Cell.BookImageCount.text = "\(picturecount) Picture"
let firstpicture = books.firstimage!
Cell.BookImage.image = UIImage(data: firstpicture)
return Cell
}