CustomCollectionViewLayout not working on Swift 3 - ios

Question

I have implemented UICollectionView and it can scroll horizontal and vertical with sticky rows and columns using below example:
Example
Github
Apps works find on Swift2 but after upgrade Swift3 CustomCollectionViewLayout giving me error
class CustomCollectionViewLayout: UICollectionViewLayout {
let numberOfColumns = 8
var itemAttributes : NSMutableArray!
var itemsSize : NSMutableArray!
var contentSize : CGSize!
override func prepare() {
if self.collectionView?.numberOfSections == 0 {
return
}
if (self.itemAttributes != nil && self.itemAttributes.count > 0) {
for section in 0..<self.collectionView!.numberOfSections {
let numberOfItems : Int = self.collectionView!.numberOfItems(inSection: section)
for index in 0..<numberOfItems {
if section != 0 && index != 0 {
continue
}
let attributes : UICollectionViewLayoutAttributes = self.layoutAttributesForItem(at: IndexPath(item: index, section: section))
if section == 0 {
var frame = attributes.frame
frame.origin.y = self.collectionView!.contentOffset.y
attributes.frame = frame
}
if index == 0 {
var frame = attributes.frame
frame.origin.x = self.collectionView!.contentOffset.x
attributes.frame = frame
}
}
}
return
}
if (self.itemsSize == nil || self.itemsSize.count != numberOfColumns) {
self.calculateItemsSize()
}
var column = 0
var xOffset : CGFloat = 0
var yOffset : CGFloat = 0
var contentWidth : CGFloat = 0
var contentHeight : CGFloat = 0
for section in 0..<self.collectionView!.numberOfSections {
let sectionAttributes = NSMutableArray()
for index in 0..<numberOfColumns {
let itemSize = (self.itemsSize[index] as AnyObject).cgSizeValue
let indexPath = IndexPath(item: index, section: section)
let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath)
attributes.frame = CGRect(x: xOffset, y: yOffset, width: (itemSize?.width)!, height: (itemSize?.height)!).integral
if section == 0 && index == 0 {
attributes.zIndex = 1024;
} else if section == 0 || index == 0 {
attributes.zIndex = 1023
}
if section == 0 {
var frame = attributes.frame
frame.origin.y = self.collectionView!.contentOffset.y
attributes.frame = frame
}
if index == 0 {
var frame = attributes.frame
frame.origin.x = self.collectionView!.contentOffset.x
attributes.frame = frame
}
sectionAttributes.add(attributes)
xOffset += (itemSize?.width)!
column += 1
if column == numberOfColumns {
if xOffset > contentWidth {
contentWidth = xOffset
}
column = 0
xOffset = 0
yOffset += (itemSize?.height)!
}
}
if (self.itemAttributes == nil) {
self.itemAttributes = NSMutableArray(capacity: self.collectionView!.numberOfSections)
}
self.itemAttributes .add(sectionAttributes)
}
let attributes : UICollectionViewLayoutAttributes = (self.itemAttributes.lastObject as AnyObject).lastObject as! UICollectionViewLayoutAttributes
contentHeight = attributes.frame.origin.y + attributes.frame.size.height
self.contentSize = CGSize(width: contentWidth, height: contentHeight)
}
override var collectionViewContentSize : CGSize {
return self.contentSize
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes! {
return self.itemAttributes[indexPath.section][indexPath.row] as! UICollectionViewLayoutAttributes
// Error in above return line and error is Type 'Any' has no subscript members
}
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
var attributes = [UICollectionViewLayoutAttributes]()
if self.itemAttributes != nil {
for section in self.itemAttributes {
let filteredArray = (section as AnyObject).filtered(
using: NSPredicate(block: { (evaluatedObject, bindings) -> Bool in
return rect.intersects(evaluatedObject.frame)
// Error in above return line and error is Value of type 'Any?' has no member 'frame'
})
) as! [UICollectionViewLayoutAttributes]
attributes.append(contentsOf: filteredArray)
}
}
return attributes
}
override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
return true
}
func sizeForItemWithColumnIndex(_ columnIndex: Int) -> CGSize {
var text : String = ""
switch (columnIndex) {
case 0:
text = "Col 0"
case 1:
text = "Col 1"
case 2:
text = "Col 2"
case 3:
text = "Col 3"
case 4:
text = "Col 4"
case 5:
text = "Col 5"
case 6:
text = "Col 6"
default:
text = "Col 7"
}
let size : CGSize = (text as NSString).size(attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 17.0)])
let width : CGFloat = size.width + 25
return CGSize(width: width, height: 30)
}
func calculateItemsSize() {
self.itemsSize = NSMutableArray(capacity: numberOfColumns)
for index in 0..<numberOfColumns {
self.itemsSize.add(NSValue(cgSize: self.sizeForItemWithColumnIndex(index)))
}
}
}
ContentCollectionViewCell
class ContentCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var contentLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
}
DateCollectionViewCell
class DateCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var dateLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
}
CollectionViewController
class CollectionViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
let dateCellIdentifier = "DateCellIdentifier"
let contentCellIdentifier = "ContentCellIdentifier"
#IBOutlet weak var collectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView .register(UINib(nibName: "DateCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: dateCellIdentifier)
self.collectionView .register(UINib(nibName: "ContentCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: contentCellIdentifier)
}
// MARK - UICollectionViewDataSource
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 5
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 8
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
print(indexPath.description)
if indexPath.section == 0 {
if indexPath.row == 0 {
let dateCell : DateCollectionViewCell = collectionView .dequeueReusableCell(withReuseIdentifier: dateCellIdentifier, for: indexPath) as! DateCollectionViewCell
dateCell.backgroundColor = UIColor.white
dateCell.dateLabel.font = UIFont.systemFont(ofSize: 13)
dateCell.dateLabel.textColor = UIColor.black
dateCell.dateLabel.text = "Donor ID"
return dateCell
} else {
let contentCell : ContentCollectionViewCell = collectionView .dequeueReusableCell(withReuseIdentifier: contentCellIdentifier, for: indexPath) as! ContentCollectionViewCell
contentCell.contentLabel.font = UIFont.systemFont(ofSize: 13)
contentCell.contentLabel.textColor = UIColor.black
contentCell.contentLabel.text = "Section"
if indexPath.section % 2 != 0 {
contentCell.backgroundColor = UIColor(white: 242/255.0, alpha: 1.0)
} else {
contentCell.backgroundColor = UIColor.white
}
return contentCell
}
} else {
if indexPath.row == 0 {
let dateCell : DateCollectionViewCell = collectionView .dequeueReusableCell(withReuseIdentifier: dateCellIdentifier, for: indexPath) as! DateCollectionViewCell
dateCell.dateLabel.font = UIFont.systemFont(ofSize: 13)
dateCell.dateLabel.textColor = UIColor.black
dateCell.dateLabel.text = String(indexPath.section)
if indexPath.section % 2 != 0 {
dateCell.backgroundColor = UIColor(white: 242/255.0, alpha: 1.0)
} else {
dateCell.backgroundColor = UIColor.white
}
return dateCell
} else {
let contentCell : ContentCollectionViewCell = collectionView .dequeueReusableCell(withReuseIdentifier: contentCellIdentifier, for: indexPath) as! ContentCollectionViewCell
contentCell.contentLabel.font = UIFont.systemFont(ofSize: 13)
contentCell.contentLabel.textColor = UIColor.black
contentCell.contentLabel.text = "Section:\(indexPath.section.description) / Row: \(indexPath.row.description)"
if indexPath.section % 2 != 0 {
contentCell.backgroundColor = UIColor(white: 242/255.0, alpha: 1.0)
} else {
contentCell.backgroundColor = UIColor.white
}
return contentCell
}
}
}
}
Thanks

Answer 1

Hello replace your CustomCollectionViewLayout with this
CustomCollectionViewLayout.swift
class CustomCollectionViewLayout: UICollectionViewLayout {
let numberOfColumns = 8
var itemAttributes : NSMutableArray!
var itemsSize : NSMutableArray!
var contentSize : CGSize!
override func prepare() {
if self.collectionView?.numberOfSections == 0 {
return
}
if (self.itemAttributes != nil && self.itemAttributes.count > 0) {
for section in 0..<self.collectionView!.numberOfSections {
let numberOfItems : Int = self.collectionView!.numberOfItems(inSection: section)
for index in 0..<numberOfItems {
if section != 0 && index != 0 {
continue
}
let attributes : UICollectionViewLayoutAttributes = self.layoutAttributesForItem(at: IndexPath(item: index, section: section))
if section == 0 {
var frame = attributes.frame
frame.origin.y = self.collectionView!.contentOffset.y
attributes.frame = frame
}
if index == 0 {
var frame = attributes.frame
frame.origin.x = self.collectionView!.contentOffset.x
attributes.frame = frame
}
}
}
return
}
if (self.itemsSize == nil || self.itemsSize.count != numberOfColumns) {
self.calculateItemsSize()
}
var column = 0
var xOffset : CGFloat = 0
var yOffset : CGFloat = 0
var contentWidth : CGFloat = 0
var contentHeight : CGFloat = 0
for section in 0..<self.collectionView!.numberOfSections {
let sectionAttributes = NSMutableArray()
for index in 0..<numberOfColumns {
let itemSize = (self.itemsSize[index] as AnyObject).cgSizeValue
let indexPath = IndexPath(item: index, section: section)
let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath)
attributes.frame = CGRect(x: xOffset, y: yOffset, width: (itemSize?.width)!, height: (itemSize?.height)!).integral
if section == 0 && index == 0 {
attributes.zIndex = 1024;
} else if section == 0 || index == 0 {
attributes.zIndex = 1023
}
if section == 0 {
var frame = attributes.frame
frame.origin.y = self.collectionView!.contentOffset.y
attributes.frame = frame
}
if index == 0 {
var frame = attributes.frame
frame.origin.x = self.collectionView!.contentOffset.x
attributes.frame = frame
}
sectionAttributes.add(attributes)
xOffset += (itemSize?.width)!
column += 1
if column == numberOfColumns {
if xOffset > contentWidth {
contentWidth = xOffset
}
column = 0
xOffset = 0
yOffset += (itemSize?.height)!
}
}
if (self.itemAttributes == nil) {
self.itemAttributes = NSMutableArray(capacity: self.collectionView!.numberOfSections)
}
self.itemAttributes .add(sectionAttributes)
}
let attributes : UICollectionViewLayoutAttributes = (self.itemAttributes.lastObject as AnyObject).lastObject as! UICollectionViewLayoutAttributes
contentHeight = attributes.frame.origin.y + attributes.frame.size.height
self.contentSize = CGSize(width: contentWidth, height: contentHeight)
}
override var collectionViewContentSize : CGSize {
return self.contentSize
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes! {
//return self.itemAttributes[indexPath.section][indexPath.row] as! UICollectionViewLayoutAttributes
let arr = self.itemAttributes[indexPath.section] as! NSMutableArray
return arr[indexPath.row] as! UICollectionViewLayoutAttributes
}
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
var attributes = [UICollectionViewLayoutAttributes]()
if self.itemAttributes != nil {
for section in self.itemAttributes {
let filteredArray = (section as! NSMutableArray).filtered(
using: NSPredicate(block: { (evaluatedObject , bindings) -> Bool in
let a = evaluatedObject as! UICollectionViewLayoutAttributes
return rect.intersects(a.frame)
})
) as! [UICollectionViewLayoutAttributes]
attributes.append(contentsOf: filteredArray)
}
}
return attributes
}
override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
return true
}
func sizeForItemWithColumnIndex(_ columnIndex: Int) -> CGSize {
var text : String = ""
switch (columnIndex) {
case 0:
text = "Col 0"
case 1:
text = "Col 1"
case 2:
text = "Col 2"
case 3:
text = "Col 3"
case 4:
text = "Col 4"
case 5:
text = "Col 5"
case 6:
text = "Col 6"
default:
text = "Col 7"
}
let size : CGSize = (text as NSString).size(attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 17.0)])
let width : CGFloat = size.width + 25
return CGSize(width: width, height: 30)
}
func calculateItemsSize() {
self.itemsSize = NSMutableArray(capacity: numberOfColumns)
for index in 0..<numberOfColumns {
self.itemsSize.add(NSValue(cgSize: self.sizeForItemWithColumnIndex(index)))
}
}
}

Answer 2

I'm using https://github.com/bartjacobs/StickyHeadersCollectionView
For Swift 4 with xCode 9.2 my problem was that StickyHeadersCollectionViewFlowLayout stopped working when Swift 3 #objc inference was set to Default or Off (setting it to On the problem was gone) but since Swift 3 #objc inference is something that should be resolved I took a deeper look and found out that I only needed to use #objc on UICollectionViewDelegate methods (for me, to be more precise was just the last one):
// MARK: - Collection View Delegate Flow Layout Methods
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.bounds.width, height: self.gridCellHeight)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets.zero
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0.0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0.0
}
#objc func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
if useStickyHeader {
return CGSize(width: collectionView.bounds.width, height: self.gridCellHeight)
} else {
return CGSize.zero
}
}