I need to implement horizontal UICollectionView.
Sometimes, I need to update the data, So I decided to implement a refreshcontrol.
I called reloadData() with refreshcontrol. It seems to be working, but cellForItemAt is not called the correct time.
So, when the cell count has changed it will be crashed.
class ViewController: UIViewController, UICollectionViewDelegate {
#IBOutlet weak var collectionView: UICollectionView!
private let refreshControl = UIRefreshControl()
private var cellCount = 1
override func viewDidLoad() {
super.viewDidLoad()
collectionView.delegate = self
collectionView.dataSource = self
collectionView.refreshControl = refreshControl
refreshControl.addTarget(self, action: #selector(refresh(sender:)), for: .valueChanged)
collectionView.register(UINib(nibName: "TopCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "Cell")
if let layout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout {
layout.scrollDirection = .horizontal // not working
// layout.scrollDirection = .vertical //working
}
}
#objc func refresh(sender: UIRefreshControl) {
cellCount = cellCount + 1
collectionView.reloadData()
sender.endRefreshing()
}
}
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return cellCount
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell: TopCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! TopCollectionViewCell
return cell
}
}
If the direction change to vertical, it is working.
Is it correct behavior? or just a bug?
Set the alwaysBounceVertical property of collectionView as true in viewDidLoad(), i.e.
collectionView.alwaysBounceVertical = true
Related
I want to ask. I make a custom menubar from collectionView and I want to link and change my menubar of collection view and the data from another collectionView while swiping. Here a picture what I'm try to make
but while try to swipe to left and right my menu bar is not following, I already make a reference to capture the value. but it's still not work. here is my code
class SegmentedView: UIView {
let collectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
return cv
}()
let knowledge = ["Pengetahuan", "Keterampilan", "Sikap"]
var selectedMenu: CGFloat?
}
extension SegmentedView: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return knowledge.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId", for: indexPath) as! SegmentedCell
let item = knowledge[indexPath.item]
cell.nameLabel.text = item
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedMenu = CGFloat(indexPath.item) * frame.width
}
}
// This from my SegmentedViewController
class SegmentedViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
#IBOutlet weak var segmentedViews: SegmentedView!
let cellId = "assesmentCell"
let colors: [UIColor] = [UIColor.blue, UIColor.yellow, UIColor.green]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
setupCollection()
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
print(scrollView.contentOffset.x / 3)
segmentedViews.selectedMenu = scrollView.contentOffset.x / 3
}
func setupCollection() {
if let flowLayout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout {
flowLayout.scrollDirection = .horizontal
flowLayout.minimumLineSpacing = 0
}
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellId)
collectionView.dataSource = self
collectionView.delegate = self
collectionView.isPagingEnabled = true
}
}
thank you.
Your selectedMenu property does not listen for an event with the didSet property observer. So when you set selectedMenu in scrollViewDidScroll, nothing happens.
It may be a solution:
var selectedMenu: CGFloat? {
didSet {
collectionView.selectItem(at: <#T##IndexPath?#>, animated: <#T##Bool#>, scrollPosition: <#T##UICollectionView.ScrollPosition#>)
}
}
But be careful with the collectionView(_:didSelectItemAt:) method of SegmentedView, it can bring some unwanted behaviors. You can use a delegate pattern to trigger the method in another class.
I have a ViewController with a CollectionView and would like to put the UICollectionViewDataSource in an extra-class, so that it can be reused. (I'm not using the interface builder).
Therefore, I created an extra-class:
class MyDataSource: NSObject, UICollectionViewDelegate, UICollectionViewDataSource {
public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 5
}
public func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MYIDENTIFIER", for: indexPath)
cell.backgroundColor = .blue
return cell
}
}
In the ViewController with the CollectionView, I set it:
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "MYIDENTIFIER")
let myDataSource = MyDataSource()
collectionView.delegate = myDataSource
collectionView.dataSource = myDataSource
}
However, the collectionView will stay empty - there are no cells on it.
However, if I put all the DataSource Functions into the ViewController class itself and set the delegate and DataSource to self, then everything works.
Is it not possible to outsource the UICollectionViewDataSource in other files, or is there anything more you have to do?
Just in case. Here is the reason I was saying about calling the init method. #Andrey Chernukha, sorry if it caused any confusion. This is why I said that it works with the init but I guess it is the same reason as Pascal
import UIKit
class ViewController: UIViewController {
lazy var collectionView : UICollectionView = {
let layout = UICollectionViewFlowLayout()
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.backgroundColor = .green
return cv
}()
var dataSource : CustomDataSource!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.view.addSubview(collectionView)
collectionView.frame = CGRect(x: 0, y: 0, width: self.view.frame.width, height: self.view.frame.height)
dataSource = CustomDataSource(collectionView: collectionView)
}
}
class CustomDataSource : NSObject, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {
let collectionView : UICollectionView
init(collectionView: UICollectionView) {
self.collectionView = collectionView
super.init()
self.collectionView.dataSource = self
self.collectionView.delegate = self
self.collectionView.register(Cell.self, forCellWithReuseIdentifier: "cell")
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
cell.backgroundColor = .red
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 100, height: 100)
}
}
class Cell : UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: frame)
setupViews()
}
func setupViews() {
self.backgroundColor = .red
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
I tested it and the reason is that dataSource is weak in a collectionView so it is deallocated immediately after it's instantiated if declared in viewDidLoad()
thanks for the help! I tried what Galo suggested, but for me this didn't work. However, I found the solution:
You have to initialize the delegate as property of the ViewController, and not in its viewDidLoad function! Then everything is working correctly!
let myDataSource = MyDataSource()
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "MYIDENTIFIER")
collectionView.delegate = myDataSource
collectionView.dataSource = myDataSource
}
It's another scope issue often been overlooked.
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "MYIDENTIFIER")
let myDataSource = MyDataSource(). //See the problem here?
collectionView.delegate = myDataSource
collectionView.dataSource = myDataSource
} //myDataSource will be released!
I created a UICollectionView as a major UICollectionView and each collectionViewCell has another UICollectionView "B" as it's subview
Then I add a tapGesture in "B". but "B" can't trigger this gesture.
Following is my main code:
Main UICollectionView
import Foundation
import UIKit
class mainViewController :UIViewController,UICollectionViewDataSource,UICollectionViewDelegate {
#IBOutlet weak var mainCollectionView: UICollectionView!
override func viewDidLoad() {
self.mainCollectionView.registerNib(UINib(nibName: "OuterCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "OuterCollectionViewCell")
self.mainCollectionView.delegate = self
self.mainCollectionView.dataSource = self
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
return 1
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
{
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("OuterCollectionViewCell", forIndexPath: indexPath) as! OuterCollectionViewCell
return cell
}
}
UICollectionView B:
class OuterCollectionViewCell: UICollectionViewCell,UICollectionViewDataSource, UICollectionViewDelegate {
#IBOutlet weak var InnerCollectionView: UICollectionView!
override func awakeFromNib() {
super.awakeFromNib()
InnerCollectionView.registerNib(UINib(nibName: "InnerCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "CellInner")
}
func handleTapGesture(sender: UITapGestureRecognizer) {
print("tapguesture")
}
override func didMoveToWindow(){
let tapGesture = UITapGestureRecognizer(target: self, action: "handleTapGesture:")
InnerCollectionView.backgroundColor = UIColor.redColor()
InnerCollectionView.addGestureRecognizer(tapGesture)
InnerCollectionView.delegate = self
InnerCollectionView.dataSource = self
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 1
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CellInner", forIndexPath: indexPath) as! InnerCollectionViewCell
return cell
}
}
This issue is bugging me an whole day. Is there anyone who has any ideas about how to fix this issue?
I have uploaded the project into github: https://github.com/dengchicheng/Test2
update－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
today I init the innerCollectionView by code programmably instead of init by NIB. and it works
let flowLayout = UICollectionViewFlowLayout()
flowLayout.scrollDirection = UICollectionViewScrollDirection.Horizontal
let InnerCollectionView = UICollectionView(frame: CGRect(x: 0, y: 0, width: 800, height: 600), collectionViewLayout: flowLayout)
I don't know what the NIB did to the UIcollectionview
I did set the userInteractive to be true in the interface builder
I got some issues with the following code: I created a custom Cell with a Custom UICollectionView class. I used Xib files instead of the storyboard.
It never calls the didSelectItemAtIndexPath method but why? I am really desperate :'(.
import UIKit
class CustomCollectionView: UICollectionView, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
var refreshControl : UIRefreshControl = UIRefreshControl()
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.delegate = self
self.dataSource = self
var flowLayout:UICollectionViewFlowLayout = UICollectionViewFlowLayout()
flowLayout.scrollDirection = UICollectionViewScrollDirection.Vertical
self.collectionViewLayout = flowLayout
self.refreshControl.addTarget(self, action: "refreshData:", forControlEvents: UIControlEvents.ValueChanged)
self.addSubview(refreshControl)
self.userInteractionEnabled = true
self.registerClass(CustomCollectionViewCell.self, forCellWithReuseIdentifier: "outfit")
self.registerNib(UINib(nibName: layoutHelper.getCellXibName("CustomCollectionViewCell"), bundle: nil), forCellWithReuseIdentifier: "outfit")
self.backgroundColor = UIColor.whiteColor()
}
//
// MARK: UICollectionViewDataSource - Methods
//
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
var cell : CustomCollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier("outfit", forIndexPath: indexPath) as! CustomCollectionViewCell
cell.label.text = "Outfit #" + String(indexPath.row)
let url = NSURL(string: "http://placehold.it/177x370")
cell.imageView.sd_setImageWithURL(url, completed: nil)
return cell
}
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
println("at index path %i", indexPath.row)
}
I am interested in having a collectionview as a part of a collection view cell but for some reason cannot figure out how this would be done. Where would I implement the necessary methods for the cells collectionview?
There's an article that Ash Furrow wrote that explains how to put an UICollectionView inside an UITableViewCell. It's basically the same idea when using it inside an UICollectionViewCell.
Everything is done programatically. No storyboards.
I added a UICollectionView inside my UICollectionViewCell. I also show how to add again a UICollectionViewCell inside the created UICollectionView to have this result
import UIKit
class CategoryCell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
private let cellId = "cell"
override init(frame: CGRect) {
super.init(frame: frame)
setupViews()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
let appsCollectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
return collectionView
}()
func setupViews() {
backgroundColor = .blue
addSubview(appsCollectionView)
appsCollectionView.delegate = self
appsCollectionView.dataSource = self
appsCollectionView.register(AppCell.self, forCellWithReuseIdentifier: cellId)
addConstrainstWithFormat("H:|-8-[v0]-8-|", views: appsCollectionView)
addConstrainstWithFormat("V:|[v0]|", views: appsCollectionView)
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 5
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath)
return cell
}
}
class AppCell: UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: frame)
setupViews()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setupViews(){
backgroundColor = .red
}
}
My UICollectionViewController
import UIKit
class FeaturedAppsController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
let cellId = "cell"
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
collectionView?.backgroundColor = .white
collectionView?.register(CategoryCell.self, forCellWithReuseIdentifier: cellId)
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath)
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(view.frame.width, 150)
}
}
The whole explanation can be found and was developed by "Let´s build that app": https://www.youtube.com/watch?v=Ko9oNhlTwH0&list=PL0dzCUj1L5JEXct3-OV6itP7Kz3tRDmma
This is too late for this answer but it might help others. This is an example of UICollectionView inside a UICollectionViewCell.
Lets start by having a mainCollectionView. Then on each cell of this collection create and initialize a new UICollectionView and right place to do that is in this following delegate of UICollectionView
func collectionView(collectionView: UICollectionView, willDisplayCell cell: UICollectionViewCell, forItemAtIndexPath indexPath: NSIndexPath)
e.g I initialize the MainCollectionViewCell here and then MainCollectionViewCell handles the logic to create a new UICollectionView
guard let collectionViewCell = cell as? MainCollectionViewCell else { return }
collectionViewCell.delegate = self
let dataProvider = ChildCollectionViewDataSource()
dataProvider.data = data[indexPath.row] as NSArray
let delegate = ChildCollectionViewDelegate()
collectionViewCell.initializeCollectionViewWithDataSource(dataProvider, delegate: delegate, forRow: indexPath.row)
collectionViewCell.collectionViewOffset = storedOffsets[indexPath.row] ?? 0
Here is the initializer on MainCollectionViewCell that creates a new UICollectionView
func initializeCollectionViewWithDataSource<D: protocol<UICollectionViewDataSource>,E: protocol<UICollectionViewDelegate>>(dataSource: D, delegate :E, forRow row: Int) {
self.collectionViewDataSource = dataSource
self.collectionViewDelegate = delegate
let flowLayout = UICollectionViewFlowLayout()
flowLayout.scrollDirection = .Horizontal
let collectionView = UICollectionView(frame: self.bounds, collectionViewLayout: flowLayout)
collectionView.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: reuseChildCollectionViewCellIdentifier)
collectionView.backgroundColor = UIColor.whiteColor()
collectionView.dataSource = self.collectionViewDataSource
collectionView.delegate = self.collectionViewDelegate
collectionView.tag = row
self.addSubview(collectionView)
self.collectionView = collectionView
collectionView.reloadData()
}
Hope that helps !!
I did an example for this and put in on github. It demonstrates the use UICollectionView inside a UICollectionViewCell.
https://github.com/irfanlone/Collection-View-in-a-collection-view-cell
Easiest solution for collectionview inside collectionview using storyboard and Swift 5
Please refer this link for nested collectionview example
import UIKit
class ParentViewController:UIViewController,UICollectionViewDataSource,UICollectionViewDelegate {
//MARK: Declare variable
//MARK: Decalare outlet
#IBOutlet weak var outerCollectionView: UICollectionView!
#IBOutlet weak var pageControl: UIPageControl!
let outerCount = 4
//MARK: Decalare life cycle methods
override func viewDidLoad() {
super.viewDidLoad()
pageControl.numberOfPages = outerCount
}
//MARK: Collection View delegate methods
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return outerCount
}
//MARK: Collection View datasource methods
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "OuterCell", for: indexPath) as! OuterCollectionViewCell
cell.contentView.backgroundColor = .none
return cell
}
//MARK:- For Display the page number in page controll of collection view Cell
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let visibleRect = CGRect(origin: self.outerCollectionView.contentOffset, size: self.outerCollectionView.bounds.size)
let visiblePoint = CGPoint(x: visibleRect.midX, y: visibleRect.midY)
if let visibleIndexPath = self.outerCollectionView.indexPathForItem(at: visiblePoint) {
self.pageControl.currentPage = visibleIndexPath.row
}
}
}
class OuterCollectionViewCell: UICollectionViewCell ,UICollectionViewDataSource,UICollectionViewDelegate {
#IBOutlet weak var InnerCollectionView: UICollectionView!
override func awakeFromNib() {
super.awakeFromNib()
InnerCollectionView.delegate = self
InnerCollectionView.dataSource = self
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
6
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "InnerCell", for: indexPath) as! InnerCollectionViewCell
cell.contentView.backgroundColor = .green
return cell
}
}
class InnerCollectionViewCell: UICollectionViewCell{
}