All CollectionViewCell height equal to largest cell label dynamic content - ios

Question

I need to create a vertical CollectionView which have a dynamic label and all CollectionViewCell height should be same to the largest cell content. How to calculate largest cell height and assign that height to every cell?
I have tried many solution but none is working for me.
Any solution pls
Thanks in advance.

Answer 1

Start by adding the following UILabel Extension (add anywhere outside of the ViewController):
extension UILabel{
public var getHeight: CGFloat {
let label = UILabel(frame: CGRect(x: 0, y: 0, width: frame.width, height: CGFloat.greatestFiniteMagnitude))
label.numberOfLines = 0
label.lineBreakMode = NSLineBreakMode.byWordWrapping
label.font = font
label.text = text
label.attributedText = attributedText
label.sizeToFit()
return label.frame.height
}
}
Then you can calculate the height for each label while the collection view cell is rendering. In the following, I check to see if the new height is greater then the last tallest height - this is saved to my variable called tallestCellHeight. Use this variable to set the height of the cell.
var tallestCellHeight: CGFloat = 0
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return messages.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "testCell", for: indexPath) as! testCell
cell.testLabel.text = messages[indexPath.row]
let currentCellHeight = cell.testLabel.getHeight
if currentCellHeight > tallestCellHeight {
tallestCellHeight = currentCellHeight
print(tallestCellHeight)
}
cell.backgroundColor = .tertiarySystemFill
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
CGSize(width: 150, height: tallestCellHeight)
}
After the collection view has rendered, I will have the tallest cell height saved to the variable tallestCellHeight.
Lastly, reload the collection view on the main thread in viewDidLoad()
DispatchQueue.main.async {
self.collectionView.reloadData()
}
Don't forget to include UICollectionViewDelegate, UICollectionViewDataSource and UICollectionViewDelegateFlowLayout
Entire Code
import UIKit
let messages: [String] = ["hello and welcome", "this is a really cool app", "this is awesome", "welcome to the test for my new application", "hello everyone"]
class testCell: UICollectionViewCell {
#IBOutlet weak var testLabel: UILabel!
}
class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
#IBOutlet weak var collectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
var tallestCellHeight: CGFloat = 0
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return messages.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "testCell", for: indexPath) as! testCell
cell.testLabel.text = messages[indexPath.row]
let currentCellHeight = cell.testLabel.getHeight
if currentCellHeight > tallestCellHeight {
tallestCellHeight = currentCellHeight
print(tallestCellHeight)
}
cell.backgroundColor = .tertiarySystemFill
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
CGSize(width: 150, height: tallestCellHeight)
}
}
extension UILabel{
public var getHeight: CGFloat {
let label = UILabel(frame: CGRect(x: 0, y: 0, width: frame.width, height: CGFloat.greatestFiniteMagnitude))
label.numberOfLines = 0
label.lineBreakMode = NSLineBreakMode.byWordWrapping
label.font = font
label.text = text
label.attributedText = attributedText
label.sizeToFit()
return label.frame.height
}
}