I am having UICollectionView inside a UITableViewCell and its delegate and datasource are declared there in table cell class. It works fine for first time loading but later on changes it's size when I scroll collection.
I noticed sizeForItemAt is called only while loading but not while setting the cells during scroll.
class HomeCell: UITableViewCell {
#IBOutlet weak var collHomeSongs: UICollectionView!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
func setCollection() {
collHomeSongs.delegate = self
collHomeSongs.dataSource = self
}
}
extension HomeCell: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout{
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize.init(width: 120, height: 180)
}
}
I just got it's solution this problem arises in Xcode 11+, and solution to it is set collection view automatic size to "None".
Refer: Why on Xcode 11, UICollectionViewCell changes size as soon as you scroll (I already set size in sizeForItem AtIndexPath:)?
Related
Delegate isn't being called from tableViewCell. Here is UICollectionViewDelegate and UICollectionViewDataSource code
extension HomeVC:UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout{
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 4
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ProductCell", for: indexPath)
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print("ok")
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let lay = collectionViewLayout as! UICollectionViewFlowLayout
lay.sectionInset = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
lay.minimumInteritemSpacing = 0
lay.minimumLineSpacing = 0
collectionView.collectionViewLayout = lay
let size = (collectionView.frame.size.width-10) / 2
return CGSize(width: size, height: size)
}
}
swift 5
//MARK:- Tableview Datasource method
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier:"RecentLoanApplicationCell") as! RecentLoanApplicationCell
cell.collectionVC.delegate = self
cell.collectionVC.dataSource = self
cell.btnViewAll.addTarget(self, action: #selector(btnViewALLTap(button:)), for: .touchUpInside)
DispatchQueue.main.async {
cell.collectionVC.reloadData()
}
return cell
}
//MARK:- Tableview Cell in side custom cell Register for collectionView cell
class RecentLoanApplicationCell: UITableViewCell {
#IBOutlet var collectionVC:UICollectionView!
override func awakeFromNib() {
super.awakeFromNib()
self.collectionVC.register(UINib.init(nibName:"RecentLoanCollectionViewCell", bundle: nil), forCellWithReuseIdentifier:"RecentLoanCollectionViewCell")
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
}
}
// Same ControllerView call
//MARK:- Collection DataSource & Delegate
extension HomeViewController : 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:"RecentLoanCollectionViewCell", for: indexPath) as! RecentLoanCollectionViewCell
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
debugPrint("didSelectItemAt ==>\(indexPath.row)")
}
Here is the code how I done for same inside TableViewCell using collectionView and performed selection :
Code inside TableView datasource method :
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "BasicCarColorCell", for: indexPath) as! BasicCarColorCell
cell.dataSource = preloads.colors
cell.collectionViewSetup()
cell.delegate = self
return cell
}
Code for TableViewCell:
protocol BasicCarColorCellDelegate {
func colorCell(cell:BasicCarColorCell, didSelect color: Color)
}
class BasicCarColorCell: UITableViewCell {
var dataSource = Array<Color>()
var selectedColor = Color()
#IBOutlet weak var textView: RSKPlaceholderTextView!
#IBOutlet weak var guideLineMessage:UILabel!
#IBOutlet weak var collectionView: UICollectionView!
var delegate: BasicCarColorCellDelegate?
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
func collectionViewSetup() {
let nib = UINib(nibName: "BasicCarColorCollectionCell", bundle: nil)
self.collectionView.register(nib, forCellWithReuseIdentifier: "BasicCarColorCollectionCell")
let flowLayout = UICollectionViewFlowLayout()
flowLayout.minimumLineSpacing = 0
flowLayout.minimumInteritemSpacing = 0
flowLayout.scrollDirection = .horizontal
collectionView.collectionViewLayout = flowLayout
collectionView.dataSource = self
collectionView.delegate = self
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
extension BasicCarColorCell: UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return self.dataSource.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "BasicCarColorCollectionCell", for: indexPath) as! BasicCarColorCollectionCell
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let height = collectionView.bounds.size.height-2
let width = height-20
return CGSize(width: width, height:height)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 1, left: 10, bottom: 1, right: 10)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let color = self.dataSource[indexPath.item]
self.selectedColor = color
delegate?.colorCell(cell: self, didSelect: self.selectedColor)
collectionView.reloadData()
}
}
And to handle the selection of collectionView just implement the method of custom protocol written in TableViewCell in ViewController:
func colorCell(cell: BasicCarColorCell, didSelect color: Color) {
//self.selectedCarColor = color.value
}
You can do it in same pattern as per your need.
Hope it'll help!
You need to set datasource and delegate for collectionView, every time in Tableview delegate CellForRowAtIndexPath.
I am trying to modify the size of the cells that the UICollectionview contains. I believe that the sizeForItemAtIndexPath should do the trick. Yet nothing is happening.
I have looked into similar questions, they have advised doing the same thing. I am sort of suspicious of my inheritance.
The problem is that the cells remain in the same size regardless of the value they were fed in.
class HikeViewController: UIViewController {
var test: Int?
#IBOutlet weak var options: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.navigationBar.prefersLargeTitles = false
print(test!)
options.dataSource = self
options.delegate = self
}
}
extension HikeViewController: UICollectionViewDelegate, UICollectionViewDataSource {
//collectionCell
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 2
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
var cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionCell", for: indexPath as IndexPath)
cell.backgroundColor = UIColor.green
return cell
}
func collectionView(collectionView : UICollectionView,layout collectionViewLayout:UICollectionViewLayout,sizeForItemAtIndexPath indexPath:NSIndexPath) -> CGSize
{
return CGSize(width: 400, height: 500)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print(indexPath.row)
}
}
And when I conform to UICollectionViewDelegateFlowLayoutthe app termainates where I set the followings:
options.dataSource = self
options.delegate = self
And the error is:
Could not cast value of type 'HikingClub.HikeViewController' (0x108e1f948) to 'UICollectionViewDataSource' (0x10e723ff0).
It's worth adding that I have made sure of the connection between HikeViewController and the storyboard.
extension HikeViewController: UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
}
It should be something like this
Make your extension a subclass of UICollectionViewDelegateFlowLayout
Use the following function
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
// code
}
You need to specify that you implement the protocol UICollectionViewDelegateFlowLayout in your class declaration.
extension HikeViewController: UICollectionViewDelegateFlowLayout {}
also you have are not calling the delegate method, just defining a new one.
check the first parameter (collectionView -> _ collectionView)
func collectionView(_ collectionView : UICollectionView,layout collectionViewLayout:UICollec
I have been trying to implement a vertical collection view inside a horizontal collection view. I have succeeded in my venture up to great extent. But when the device is rotated from portrait to landscape mode, the vertical collection view cells do not resize. Although the cells resize properly when the device enters from landscape to portrait mode. Even the horizontal collection view cells resize properly as I have invalidated the flow layout inside the viewWillTransitionToSize function. I have implemented the same function (with other functions like numberOfItemsAtIndexPath, cellForItemAt, sizeForItemAt, , etc.) for vertical collection view too (inside a class "HorizontalCollectionViewCell" in a separate CocoaTouch file). But all in vein. All the view and subviews (including the two collection views) have been created using storyboard (not code). I have been searching for the solution for last 1 week , but haven't succeeded yet. Kindly help me find a proper solution for this problem.
Here is the code inside ViewController file:-
import UIKit
class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
#IBOutlet weak var horizontalView: UIView! // Container View for horizontal Collection View.
#IBOutlet weak var horizontalCollectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
horizontalCollectionView.delegate = self
horizontalCollectionView.dataSource = self
menuBarCollectionView.delegate = self
menuBarCollectionView.dataSource = self
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if collectionView == menuBarCollectionView {
let cell = menuBarCollectionView.dequeueReusableCell(withReuseIdentifier: "menuButtonsCell", for: indexPath) as! MenuBarCollectionViewCell
cell.menuButtonsLabel.text = menuButtonsName[indexPath.row]
return cell
}
let cell = horizontalCollectionView.dequeueReusableCell(withReuseIdentifier: "horizontalCell", for: indexPath) as! HorizontalCollectionViewCell
return cell
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
if collectionView == menuBarCollectionView {
let menuButtonWidthFactor = self.menuBarView.frame.width - 1
return CGSize(width: menuButtonWidthFactor / 3, height: 35)
}
return CGSize(width: horizontalView.frame.width, height: horizontalView.frame.height)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
if collectionView == menuBarCollectionView {
return 0.5
}
return 0
}
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
menuBarCollectionView.collectionViewLayout.invalidateLayout()
horizontalCollectionView.collectionViewLayout.invalidateLayout()
}
}
Here is the code inside subclass HorizontalCollectionViewCell file:-
import UIKit
class HorizontalCollectionViewCell: UICollectionViewCell, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
#IBOutlet weak var verticalCollectionView: UICollectionView! {
didSet {
self.verticalCollectionView.delegate = self
self.verticalCollectionView.dataSource = self
}
}
#IBOutlet weak var verticalView: UIView!
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = verticalCollectionView.dequeueReusableCell(withReuseIdentifier: "verticalCell", for: indexPath)
cell.backgroundColor = UIColor.red
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: self.verticalView.frame.width, height: 100)
}
func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
verticalCollectionView.collectionViewLayout.invalidateLayout()
}
}
I got two questions.
I am wondering why my collection view automatically load data without calling imageCollectionView.reloadData().
Solved. See comment
Why func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize is not called? I didn't see the print("collectionViewLayout called") I am trying to modify the cell's size so the cell's height equals to the collection view height
Solved. See comment
Here is the codes
class ProductInternalDetailVC: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
var selectedProduct: Product?
#IBOutlet weak var imageCollectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
imageCollectionView.delegate = self
imageCollectionView.dataSource = self
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 2
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath as IndexPath) as! ProductInternalDetailCVC
if indexPath.row == 0 {
cell.productImage.image = selectedProduct!.image1
} else {
cell.productImage.image = selectedProduct!.image2
}
cell.productImage.frame = CGRect(x: 1, y: 1, width: cell.frame.size.width-2, height: cell.frame.size.height-2)
return cell
}
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
//return CGSize(width: collectionView.frame.size.height-1, height: collectionView.frame.size.height-1)
print("collectionViewLayout called")
return CGSize(width: 10, height: 10)
}
}
class ProductInternalDetailCVC: UICollectionViewCell {
#IBOutlet weak var productImage: UIImageView!
}
Thanks for the help.
Question 2: The function signature has changed a bit. Change the function signature with this:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
...
}
And don't forget to implement the UICollectionViewDelegateFlowLayout protocol.
Question 1:
When entering the ViewController your collectionView loads the datasource of the collectionView automatically if this is your question.for example, make changes on datasource without changing the view (means without calling viewDidLoad method) you will not see the changes until you call imageCollectionView.reloadData().
I have a simple collectionview controller like this:
class ViewController1: UICollectionViewController{
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView?.delegate = self
self.collectionView?.dataSource = self
}
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: "P", for: indexPath)
return cell
}
}
In the cell there is only an uiimageview and it has this constraints:
My problem is this:
when I execute this code on iPhone 6 simulator I get this (right way):
but when I execute this code on iPhone 5 simulator I get this (wrong way: the imageview starts before the screen on the left and the width and height are wrong respect to the constraints):
I am going crazy for this problem but I dont be able to solve.
Can you help me?
You need to extend your ViewController1 to conform to UICollectionViewDelegateFlowLayout protocol. And implement methods to set size for each collection view cell like so:
class ViewController1: UICollectionViewController, UICollectionViewDelegateFlowLayout {
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView?.delegate = self
self.collectionView?.dataSource = self
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print(self.collectionView!.frame)
}
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: "P", for: indexPath)
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: self.collectionView!.frame.size.width, height: 120.0)
}
}
It has hard coded values, but you should get the idea. Collection View width should be the max size for each item, so they won't get outside the box.