My CollectionViewCell imageView is nil
My Cell File is here
class MyTicketsCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var imgTicket: UIImageView!
}
My Controller File Code is here
class MyTicketsCollectionViewController: UICollectionViewController {
var photos: [String] = ["ticket1","ticket2","ticket3","ticket4"]
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView?.register(MyTicketsCollectionViewCell.self, forCellWithReuseIdentifier: "MyTicketsCollectionViewCell")
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return photos.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyTicketsCollectionViewCell", for: indexPath) as! MyTicketsCollectionViewCell
cell.imgTicket.image = UIImage(named: photos[indexPath.row])
return cell
}
}
Error is "Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value"
When I debug it then
cell.imgTicket is nil
How solve this issue?
Try changing your code to
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyTicketsCollectionViewCell", for: indexPath) as! MyTicketsCollectionViewCell
cell.imgTicket.image = UIImage(named: photos[indexPath.row])
return cell
}
You are dequeuing ActiveTicketsCollectionViewCell but the cell is registered under MyTicketsCollectionViewCell.
There is 2 possible solutions here...
1. Might be ActiveTicketsCollectionViewCell have not the property imgTicket or you mention a wrong cell class here as u have mentioned a different cell class name MyTicketsCollectionViewCell so try to write this code.
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyTicketsCollectionViewCell", for: indexPath) as! MyTicketsCollectionViewCell
cell.imgTicket.image = UIImage(named: photos[indexPath.row])
return cell
2. Might be you have missed to connect your property (#IBOutlet weak var imgTicket: UIImageView!) with the Outlet (xib or storyboard).
Related
I inserted Label into CollectionView cell but when I made outlet this error appeared.
error: The currencyLabel outlet from the ViewController to the UILabel is invalid. Outlets cannot be connected to repeating content
class ViewController: UIViewController {
var currency = Currency.getCurrency()
#IBOutlet var currencyLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
}
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return currency.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "currencyCell", for: indexPath) as! CurrencyCollectionViewCell
let currencyList = currency[indexPath.row]
currencyLabel.text = "\(currencyList.currency) \n \(currencyList.cash)"
return cell
}
}
You need to create IBOutlet of your currencyLabel in CurrencyCollectionViewCell class, and use it like
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "currencyCell", for: indexPath) as! CurrencyCollectionViewCell
let currencyList = currency[indexPath.row]
cell.currencyLabel.text = "\(currencyList.currency) \n \(currencyList.cash)"
return cell
}
You have made a simple mistake.
You should make below outlet in CollectionViewCell not in your ViewController.
#IBOutlet var currencyLabel: UILabel!
In my code, I am trying to set the imageView of a UICollectionViewCell. The imageView is called cellImageView in the CollectionViewCell class. When the app loads up it tries to initialize this value, but it doesn't work
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "selectCell", for: indexPath) as! PhraseSelectionCell
cell.cellImageView?.image = UIImage(named: "lol")
return cell
}
Class of UICollectionViewCell
class PhraseSelectionCell: UICollectionViewCell {
#IBOutlet var cellImageView: UIImageView!
}
try debugging this way, then you can find where the bug is.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "selectCell", for: indexPath) as! PhraseSelectionCell
//debug 1
if UIImage(named: "lol") == nil {
print("image is nil, double check image name")
}
//debug 2
if cell.cellImageView == nil {
print("cellImageView outlet is nil")
}
cell.cellImageView?.image = UIImage(named: "lol")
return cell
}
I have a UICollectionViewCell defined like so:
import UIKit
class GalleryCellCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var image: UIImageView!
}
Xcode put this in automatically when I added the outlet. In my UICollectionViewController's
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
function, I then try to set an image. My code is
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! GalleryCellCollectionViewCell
let imagePackage = imagePackages?[indexPath.item]
let uiImage = imagePackage?.getUIImage()
cell.image.image = uiImage
return cell
}
In my variable viewer for the debugger, I can see that uiImage is not nil. However, cell.image is nil. Why would this be? Did I not link it up correctly in the storyboard?
You can access image with another approach using tag.
from Interface builder (IB) of the cell go to attribute tab (third tab) and set tag for the image (like 5)
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! GalleryCellCollectionViewCell
let imagePackage = imagePackages?[indexPath.item]
let uiImage = imagePackage?.getUIImage()
var cellImg:UIImageView = cell!.viewWithTag(5) as! UIImageView;
cellImg.image = uiImage
return cell
}
I have a tableView in which I have 2 custom cells, in both cells I have different CollectionView, the dataSource and delegate of both the CollectionViews is my ViewController.
So now how do I check which CollectionViews is to be configured in UICollectionView's respective methods?
Here is the view hierarchy
How do I come to know which is the collectionView that's there in the parameter of above function?
So here is my code:
class FeatureBannerTableViewCell: UITableViewCell {
#IBOutlet weak var featureCollectionView: UICollectionView!
}
class FeaturedTableViewCell: UITableViewCell {
#IBOutlet weak var FeatureTitle: UILabel!
#IBOutlet weak var seeAllButton: UIButton!
#IBOutlet weak var collectionView: UICollectionView!
}
extension ViewController: UITableViewDataSource {
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
switch indexPath.row {
case 2,3,6,7:
let cell = featuredTableView.dequeueReusableCellWithIdentifier("FeatureBannerTableViewCell", forIndexPath: indexPath) as! FeatureBannerTableViewCell
cell.featureCollectionView.dataSource = self
cell.featureCollectionView.delegate = self
return cell
default:
let cell = featuredTableView.dequeueReusableCellWithIdentifier("FeaturedTableViewCell", forIndexPath: indexPath) as! FeaturedTableViewCell
cell.collectionView.dataSource = self
cell.collectionView.delegate = self
return cell
}
}
}
extension ViewController: UICollectionViewDataSource {
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
// how do I know if this collectionView is collectionView or featureCollectionView?
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
// how do I know if this collectionView is collectionView or featureCollectionView?
}
}
I would use the tag property in UIView to identify your collection view. So when you configure your table cells in cellForRowAtIndexPath get the collection view of the cell and set its tag to something unique (I would use the row value of indexpath).
extension ViewController: UITableViewDataSource {
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
switch indexPath.row {
case 2,3,6,7:
let cell = featuredTableView.dequeueReusableCellWithIdentifier("FeatureBannerTableViewCell", forIndexPath: indexPath) as! FeatureBannerTableViewCell
cell.featureCollectionView.dataSource = self
cell.featureCollectionView.delegate = self
cell.featureCollectionView.tag = indexPath.row
return cell
default:
let cell = featuredTableView.dequeueReusableCellWithIdentifier("FeaturedTableViewCell", forIndexPath: indexPath) as! FeaturedTableViewCell
cell.collectionView.dataSource = self
cell.collectionView.delegate = self
cell.collectionView.tag = indexPath.row
return cell
}
}
}
Then in your collection view methods get the tag value and that will tell you which one of the many collection views it is.
extension ViewController: UICollectionViewDataSource {
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
// how do I know if this collectionView is collectionView or featureCollectionView?
let datasourceIndex = collectionView.tag
// now use your datasource for the following index
}
}
I think, you can make use of isKindOfClass
Example:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// get a reference to our storyboard cell
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyReuseIdentifier", for: indexPath as IndexPath) as! UICollectionViewCell
if cell.isKindOfClass(FeaturedBannerCollectionCell){
//implementation code
} else cell.isKindOfClass(FeaturedCollectionViewCell) {
//implementation code
}
return cell
}
I have a UICollectionView with a custom cell with an UIImageView in it as well as a custom class with the outlet
class theCell: UICollectionViewCell {
#IBOutlet var theImage:UIImageView!
}
I have an array of UIImage (Which only has one constant image). The image is in the main bundle.
var tempImages = [UIImage(named: "placeholder.png" )]
delegate methods
override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return tempImages.count
}
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = self.collectionView?.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! theCell
//Unexpectadly found nil
cell.theImage.image = tempImages[indexPath.row]
return cell
}
If you have added this line:
self.collectionView!.registerClass(CollectionViewCell.self, forCellWithReuseIdentifier: "cell")
then remove this first and here is complete working code:
CollectionViewController.swift
import UIKit
class CollectionViewController: UICollectionViewController {
var tempImages = [UIImage]()
override func viewDidLoad() {
super.viewDidLoad()
tempImages.append(UIImage(named: "bg.jpg")!)
}
// MARK: UICollectionViewDataSource
override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
//#warning Incomplete method implementation -- Return the number of sections
return 1
}
override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
//#warning Incomplete method implementation -- Return the number of items in the section
return tempImages.count
}
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! CollectionViewCell
// Configure the cell
cell.theImage.image = tempImages[indexPath.row]
println(cell.theImage.image)
return cell
}
}
CollectionViewCell.swift
import UIKit
class CollectionViewCell: UICollectionViewCell {
#IBOutlet var theImage:UIImageView!
}
And don't forget to assign Identifier to your cell:
Sample for more Info.
Try registering first in cellForItemAtIndexPath:
collectionView.registerNib(UINib(nibName: "FeedCell", bundle: nil), forCellWithReuseIdentifier: "cell")
EDIT
In your situation:
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
collectionView.registerNib(UINib(nibName: "FeedCell", bundle: nil), forCellWithReuseIdentifier: "cell")
let cell = self.collectionView?.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! theCell
cell.theImage.image = tempImages[indexPath.row]
return cell
}
The problem is reinitialize tempImages array so it return nil.
var tempImages = [UIImage(named: "placeholder.png" )]