The problem is that when I have UICollectionView inside UITableViewCell - UICollectionViewCell cornerRadius function not working.
Code is very simple and it was always working for me when playing with UICollectionView.
extension ExploreTableViewCell: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 5
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! ExploreCollectionViewCell
cell.thumbnail.layer.cornerRadius = 20
cell.thumbnail.clipsToBounds = true
return cell
}
Is it a bug or what? Cannot find any answer all day. Most of the people suggest to use contentView instead of the specific image inside the cell but that's not for me since I want only image to be rounded.
P.S this one works (but I want only image inside the cell to be rounded):
override func awakeFromNib() {
super.awakeFromNib()
self.layer.cornerRadius = 30
self.clipsToBounds = true
}
Related
I am currently programming an app with UICollectionView only when I start the app the CollectionView is not displayed. In my app I do not use the StoryBoard but only the ViewController. That's why I inherit from UICollectionViewController in my app. But when I start the app, the UICollectionView is simply not displayed. Through print commands I found out that the numberOfItemsInSection method is called, but the cellForItemAt indexPath is not. I also know that this will probably be a double question, but I still haven't found a solution for 2 hours. CollectionView.delegateand collectionView.dataSource are both set to = self and there are actually no problems with the constrains because I can turn the background of the UICollectionView to black, for example, and everything is displayed correctly there.
I hope someone can help me.
Best regards
// MARK: - Collectionview
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
print("Item wurde erstellt")
return messages.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! ChatMessageCollectionViewCell
let message = messages[indexPath.item]
cell.textView.text = message.message
setUpCell(cell, message)
cell.bubbleViewWidthAnchor?.constant = estimateFrameForText(text: message.message!).width + 32
print("Celle wird erstellt")
return cell
}
I think you have missed the height and width for the cell. You should also check the message array count, perhaps it is zero.
extension YouClass: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return messages.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! ChatMessageCollectionViewCell
let message = messages[indexPath.item]
cell.textView.text = message.message
setUpCell(cell, message)
cell.bubbleViewWidthAnchor?.constant = estimateFrameForText(text: message.message!).width + 32
print("Celle wird erstellt")
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collBanner.frame.width, height: 140)
}
}
I'm working with a UICollectionView where I have a UIImage with a Tap Gesture Recogniser as the cell model for my CollectionView. I also have 57 images with different names that I want to print to the console depending on which image I tap on.
Here is my code:
import UIKit
class ViewController: UIViewController {
let OLLData = OLLCases()
// MARK: - Outlets
#IBOutlet weak var collectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
// MARK: - Navigation
#IBAction func isSelected(_ sender: Any) {
print("selected \(caseName)")
}
}
//MARK: - Data source
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return OLLData.list.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PhotoCell", for: indexPath) as! PhotoCell
let image = OLLData.list[indexPath.item].image
let caseName = OLLData.list[indexPath.item].image
cell.label.text = caseName
cell.imageView.image = UIImage(named: image)
return cell
}
}
I then have another swift file (PhotoCell )where I have the IBOutlets for label and imageView.
What methods are there of doing this?
Thanks.
You can use UICollectionViewDelegate method to detect tap on cell but to use that first of all your UICollectionView need to confirm the delegate with your UIViewController like:
collectionView.delegate = self
in your viewDidLoad method.
then you need to replace
extension ViewController: UICollectionViewDataSource {
with
extension ViewController: UICollectionViewDataSource, UICollectionViewDelegate {
and use delegate method
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
}
and you can get selected image name with
let caseName = OLLData.list[indexPath.item].image
print(caseName)
and didSelectItemAt will look like:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let caseName = OLLData.list[indexPath.item].image
print(caseName)
}
EDIT:
Your extension will look like:
extension ViewController: UICollectionViewDataSource, UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return OLLData.list.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PhotoCell", for: indexPath) as! PhotoCell
let image = OLLData.list[indexPath.item].image
let caseName = OLLData.list[indexPath.item].image
cell.label.text = caseName
cell.imageView.image = UIImage(named: image)
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let caseName = OLLData.list[indexPath.item].image
print(caseName)
}
}
You should implement didSelectItemAt method, then get the cell you've selected like this:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.cellForItem(at: indexPath) as! PhotoCell
print(cell.imageView)
print(cell.label)
}
Hope this help
Add an extension for UICollectionViewDelegate below the last extension in your ViewController:
extension ViewController: UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print(OLLData.list[indexPath.item].image)
}
}
In my project, I have a UICollectionView. In the UICollectionView, I have a custom cell.
I am able to print the cell value when it is selected within "didSelectItemAt", however, if I try to edit the cell in any way within this method, it does not change.
I'm sure I'm missing something, any help would be appreciated!
#IBOutlet weak var collectionView: UICollectionView!
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return statValues.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "customCollectionViewCell", for: indexPath) as! customCollectionViewCell
cell.statLabel.text = statHeaders[indexPath.row]
cell.statLabel.textColor = UIColor(red:0.31, green:0.31, blue:0.31, alpha:1.0)
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "customCollectionViewCell", for: indexPath) as! customCollectionViewCell
print(cell.statLabel.text)
cell.backgroundColor = UIColor.yellow
collectionView.reloadData()
}
When user selects a cell, the code is correctly printing the value of the indexPath, however the backgroundColor does not change.
My guess would be that you are creating a new instance of cell instead of using the one in the collectionView
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
// Change this line
let cell = collectionView.cellForItemAtIndexPath(indexPath: indexPath)
print(cell.statLabel.text)
cell.backgroundColor = UIColor.yellow
collectionView.reloadData()
}
Also, you should probably keep an external data model for your source of truth. If you have enough collectionViews that requires scrolling, when you scroll offscreen, your cells will be reused in a random order causing cells that you did not click to be yellow.
Create a seperate array such as
var selectedStatHeaders: Set<Int>()
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "customCollectionViewCell", for: indexPath) as! customCollectionViewCell
cell.statLabel.text = statHeaders[indexPath.row]
cell.statLabel.textColor = UIColor(red:0.31, green:0.31, blue:0.31, alpha:1.0)
// Reset/configure cell each reload
if selectedStatHeaders.contains(indexPath.row) { // Can also make this into a ternary
cell.backgroundColor = UIColor.yellow
} else {
cell.backgroundColor = UIColor.whit
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedStatHeaders.insert(indexPath.row)
collectionView.reloadItemsAtIndexPath(indexPath: indexpath)
}
Hmm... Doesn't make sense if the code is able to print but the background doesn't change color. Do you mean changing back from yellow to white? Anyway, just a hunch but I suspect it's because you are calling collectionView.reloadData() after your set the backgroundColor change.
https://developer.apple.com/documentation/uikit/uicollectionview/1618078-reloaddata
This causes the collection view to discard any currently visible
items (including placeholders) and recreate items based on the current
state of the data source object.
I have the following code. For some strange reason, the cell is not registering properly and the cell is not rendered.
I expect there to be 5 purple cells but instead there is only red background.
class RateController: UICollectionViewController {
var user: User?
let cellId = "cellId"
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.backgroundColor = .red
collectionView?.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellId)
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 5
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath)
cell.backgroundColor = .purple
return cell
}
}
There's nothing wrong with your code. I pasted it right into a fresh project, defined the User class, made the necessary adjustments in the storyboard, and ran it:
So if there's a problem, it's somewhere else — not in that code!
I've been thinking about where else the problem could be; the problem you are describing would happen if you disabled the Flow layout in the storyboard and replaced it with an empty Custom layout, like this:
If you did that, set the Layout back to Flow.
I am having issues with my collectionView in Swift 3. I have found some tips on Stackoverflow, tried them out, but alas to no avail. Many mentioned to use the 'prepareReuse' method, but I could not get those to work in my code. After Scrolling down, and back up again, the images have changed. All the images are letters of the alphabet. So A,B,C are the first images to appear at the top of the view. If you scroll down, and back up, some random other letters have taken their place. My entire code is as follows:
import UIKit
class colViewController2: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
var imageData: [String] = [String]()
var imageCounter: Int = 0
var userHasHieroglyph: NSArray = ["","","C","D","E","F","G","H","I","J","K","L","M","N","O","","Q","R","S","T","U","V","W","X","Y","Z"]
override func viewDidLoad() {
super.viewDidLoad()
imageData = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
for b in imageData {
if userHasHieroglyph.contains(b) {
let newHieroglyph = b.lowercased()
imageData[imageData.index(of: b)!] = "h-"+newHieroglyph
}
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellid", for: indexPath) as! MyImageCell
cell.backgroundColor = UIColor.white
var currImage:String = ""
currImage = self.imageData[self.imageCounter]
self.imageCounter += 1
if self.imageCounter >= self.imageData.count {
self.imageCounter = 0
}
cell.image.image = UIImage(named: currImage)
return cell
}
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 26
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 90, height: 90)
}
}
I hope I am missing some small bit of code to solve this problem, but after many hours of searching on Stackoverflow, and the internet, I still can not find a solution to this problem. If anyone has a solution or tip, it would be greatly appreciated!
Greetings
The issue is that you're using imageCounter as the index into your array of images, but incrementing it instead of using the indexPath.item. Remember that the UICollectionView will reuse UICollectionViewCell instances. Basically, it will only create cell instances for those that are on the screen. If a cell scrolls off the screen and a new one takes its place (e.g. if you have "A", "B", and "C" on the screen, and scroll down so you see "B", "C", "D", the UICollectionView will reuse the "A" cell for "D". This is a bit of an oversimplification, but more or less how it works). As such, the cellForItem call will give you the information about which cell is being displayed in the indexPath parameter. In this case, you can get rid of all of the self.imageCounter logic and instead do cell.image.image = UIImage(named: imageData[indexPath.row])
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellid", for: indexPath) as! MyImageCell
cell.backgroundColor = UIColor.white
cell.image.image = UIImage(named: imageData[indexPath.row])
return cell
}