i'm moving up my tableView (via setting contentOffset) and changing a specific (row no. 1 here ) cell's height at the same time , thats why i'm getting a shaky animation and also tableView restores itself to the default position (which is not desired behavior )
my code :
func keyboardWillShow(notification:NSNotification) {
let userInfo:NSDictionary = notification.userInfo!
let keyboardFrame:NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
let keyboardRectangle = keyboardFrame.CGRectValue()
let duration = (notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double)
keyboardHeight = keyboardRectangle.height
accurateheight = accurateheight - (keyboardHeight + inputToolbar.frame.size.height) // accurateHeight is the desired CGFloat value that i want
self.tableView.beginUpdates()
self.tableView.endUpdates()
let frame = tableView.rectForRowAtIndexPath(NSIndexPath(forRow: 0, inSection: 0))
defaultRowHeight = frame.height
let cgpoint = CGPointMake(0, (CGFloat(-64 + defaultRowHeight)))
self.tableView.setContentOffset(cgpoint, animated: true) // here i'm moving up my tableView
}
in my heightForRowAtIndexPath:
override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
if indexPath.row == 0 {
return 44
}else {
return accurate height // cell's height which i'm changing
}
}
i also tried to update only specific row (the ones that i'm changing height of) like this :
var indexPath = NSIndexPath(forRow: 1, inSection: 0)
self.tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Top)
but the above didnt worked also sometimes my keyboard was not popping up.
how can i move (scroll up) my tableView and change a cell's height at the same time ?? any clue ?
Related
I have a tableView with chat bubbles.
Those bubbles are shortened if the character count is more than 250
If a user clicks on a bubble
The previous selection gets deselected (shortened)
The new selection expands and reveals the whole content
The new selections top constraint changes (from 0 to 4)
What I would like to achieve?
If a long bubble is selected already, but the user selects another bubble, I want the tableView to scroll to the position of the new selected bubble.
I'll share a video about it
Without this scrolling, the contentOffset remains the same and it looks bad.
(In the video: on the right)
Video:
Right: without the mentioned scrolling
Left: with scrolling
https://youtu.be/_-peZycZEAE
Here comes the problem:
On the left, you can notice that it is glitchy.
Random ghost cells are appearing for no reason.
Sometimes it even messes up the height of some bubbles (not in the video)
Why is it so?
Code:
func bubbleTappedHandler(sender: UITapGestureRecognizer) {
let touchPoint = sender.location(in: self.tableView)
if let indexPath = tableView.indexPathForRow(at: touchPoint) {
if indexPath == currentSelectedIndexPath {
// Selected bubble is tapped, deselect it
self.selectDeselectBubbles(deselect: indexPath)
} else {
if (currentSelectedIndexPath != nil){
// Deselect old bubble, select new one
self.selectDeselectBubbles(select: indexPath, deselect: currentSelectedIndexPath)
} else {
// Select bubble
self.selectDeselectBubbles(select: indexPath)
}
}
}
}
func selectDeselectBubbles(select: IndexPath? = nil, deselect: IndexPath? = nil){
var deselectCell : WorldMessageCell?
var selectCell : WorldMessageCell?
if let deselect = deselect {
deselectCell = tableView.cellForRow(at: deselect) as? WorldMessageCell
}
if let select = select {
selectCell = tableView.cellForRow(at: select) as? WorldMessageCell
}
// Deselect Main
if let deselect = deselect, let deselectCell = deselectCell {
tableView.deselectRow(at: deselect, animated: false)
currentSelectedIndexPath = nil
// Update text
deselectCell.messageLabel.text = self.dataSource[deselect.row].message.shortened()
}
// Select Main
if let select = select, let selectCell = selectCell {
tableView.selectRow(at: select, animated: true, scrollPosition: .none)
currentSelectedIndexPath = select
// Update text
deselectCell.messageLabel.text = self.dataSource[select.row].message.full()
}
UIView.animate(withDuration: appSettings.defaultAnimationSpeed) {
// Deselect Constraint changes
if let deselect = deselect, let deselectCell = deselectCell {
// Constarint change
deselectCell.nickNameButtonTopConstraint.constant = 0
deselectCell.timeLabel.alpha = 0.0
deselectCell.layoutIfNeeded()
}
// Select Constraint changes
if let select = select, let selectCell = selectCell {
// Constarint change
selectCell.nickNameButtonTopConstraint.constant = 4
selectCell.timeLabel.alpha = 1.0
selectCell.layoutIfNeeded()
}
}
self.tableView.beginUpdates()
self.tableView.endUpdates()
UIView.animate(withDuration: appSettings.defaultAnimationSpeed) {
if let select = select, deselect != nil, self.tableView.cellForRow(at: deselect!) == nil && deselectCell != nil {
// If deselected row is not anymore on screen
// but was before the collapsing,
// then scroll to new selected row
self.tableView.scrollToRow(at: select, at: .top, animated: false)
}
}
}
Update 1: Added Github project
Link: https://github.com/krptia/test2
I made a small version of my app, so that you can see and test what my problem is. I would be so thankful if someone could help to solve this issue! :c
First let's define what we mean by "without scrolling" - we mean that the cells more of less stay the same. So we want to find a cell that we want to be the anchor cell. From before the changes to after the changes the distances from the cell's top to the top of the screen is the same.
var indexPathAnchorPoint: IndexPath?
var offsetAnchorPoint: CGFloat?
func findHighestCellThatStartsInFrame() -> UITableViewCell? {
return self.tableView.visibleCells.filter {
$0.frame.origin.y >= self.tableView.contentOffset.y
}.sorted {
$0.frame.origin.y > $1.frame.origin.y
}.first
}
func setAnchorPoint() {
self.indexPathAnchorPoint = nil;
self.offsetAnchorPoint = nil;
if let cell = self.findHighestCellThatStartsInFrame() {
self.offsetAnchorPoint = cell.frame.origin.y - self.tableView.contentOffset.y
self.indexPathAnchorPoint = self.tableView.indexPath(for: cell)
}
}
we call this before we start doing stuff.
func bubbleTappedHandler(sender: UITapGestureRecognizer) {
self.setAnchorPoint()
....
Next we need to set the content offset after we are doing doing our changes so that the cell moves back to where it is suppose to.
func scrollToAnchorPoint() {
if let indexPath = indexPathAnchorPoint, let offset = offsetAnchorPoint {
let rect = self.tableView.rectForRow(at: indexPath)
let contentOffset = rect.origin.y - offset
self.tableView.setContentOffset(CGPoint.init(x: 0, y: contentOffset), animated: false)
}
}
Next we call it after we are done doing our changes.
self.tableView.beginUpdates()
self.tableView.endUpdates()
self.tableView.layoutSubviews()
self.scrollToAnchorPoint()
The animation can be a little strange because there is a lot going on at the same time. We are changing the content offset and the sizes of the cell at the same time, but if you place your finger next to the first cell that top is visible you will see it ends up in the correct place.
Try using this willDisplay api on UITableViewDelegate
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
if (indexPath == currentSelectedIndexPath) {
// logic to expand your cell
// you don't need to animate it since still not visible
}
}
Replace your code for bubbleTappedHandler with this and run and check:
func bubbleTappedHandler(sender: UITapGestureRecognizer) {
let touchPoint = sender.location(in: self.tableView)
if let indexPath = tableView.indexPathForRow(at: touchPoint) {
if indexPath == currentSelectedIndexPath {
currentSelectedIndexPath = nil
tableView.reloadRows(at: [indexPath], with: .automatic)
} else {
if (currentSelectedIndexPath != nil){
if let prevSelectedIndexPath = currentSelectedIndexPath {
currentSelectedIndexPath = indexPath
tableView.reloadRows(at: [prevSelectedIndexPath, indexPath], with: .automatic)
}
} else {
currentSelectedIndexPath = indexPath
tableView.reloadRows(at: [indexPath], with: .automatic)
}
}
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1, execute: { [weak self] in
let currentIndexPath = self?.currentSelectedIndexPath ?? indexPath
self?.tableView.scrollToRow(at: currentIndexPath, at: .top, animated: false)
})
}
}
You can use tableView?.scrollToRow. For example
let newIndexPath = IndexPath(row: 0, section: 0) // put your selected indexpath and section here
yourTableViewName?.scrollToRow(at: newIndexPath, at: UITableViewScrollPosition.top, animated: true) // give the desired scroll position to tableView
Available scroll positions are .none, .top, .middle, .bottom
This glitch is because of a small mistake. Just do these 2 things and the issue will be resolved.
Set tableView's rowHeight and estimatedRowHeight in `viewDidLoad
tableView.estimatedRowHeight = 316 // Value taken from your project. This may be something else
tableView.rowHeight = UITableView.automaticDimension
Remove the estimatedHeightForRowAt and heightForRowAt delegate methods from your code.
I am stuck at this for a while now, and while I think I know what is the issue I am still not able to solve it. I am working with tableView with each cell having countdown bar animation. Each cell has a custom time duration set by the user. Then a bar animation slides as the time elapses.
I am using CADisplayLink to get this animation running, this code is written in controller file and I am just changing the width of a UIView as the time elapses:
#objc func handleProgressAnimation() {
let currenttime = Date()
let elapsed = currenttime.timeIntervalSince(animationStartDate)
let totalWidth: Double = 400.0
print(elapsed)
let arrayLength = durationBar.count
var i: Int = 0
for _ in 0..<arrayLength {
let indexPath = IndexPath(row: i, section: 0)
let percentage = (elapsed / Double(durationBar[i].durationTime))
let newWidth = Double(totalWidth - (totalWidth * percentage))
durationBar[i].width = newWidth
if (percentage < 1)
{
if let cell = listTableView.cellForRow(at: indexPath) as! listTableViewCell? {
cell.timeRemainingView.frame.size.width = CGFloat(durationBar[indexPath.row].width)
}
}
else {
if let cell = listTableView.cellForRow(at: indexPath) as! listTableViewCell? {
cell.timeRemainingView.frame.size.width = 400
cell.timeRemainingView.isHidden = true
}
}
i = i + 1
}
}
When all the bars are decreasing, everything goes fine but as one of the cells time is completed then the UIView width becomes zero and then as the user scrolls that cell is reused and this vanishes the progress bar from other cells where there is still time.
I am using prepareforsegue() method to reset the width of the bar to 400(default value) but that doesn't seem to work.
This is cellforRow code:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellid, for: indexPath) as! listTableViewCell
cell.testlabel.text = "\(duration[indexPath.row].durationTime)"
cell.timeRemainingView.frame.size.width = CGFloat(durationBar[indexPath.row].width)
return cell
}
And this is PrepareForReuse()
override func prepareForReuse() {
super.prepareForReuse()
self.timeRemainingView.frame.size.width = 400
self.timeRemainingView.isHidden = false
}
Here is a screenshot. You can see in some cells the time is up, but in others there is still time remaining but the progress bar has disappeared.
You have to set the frame again. width is a get-only property.
I'm currently developing an iOS app using swift and I get some problem trying to add animations to UIViews inside a cell.
It's a menu using UITableView with sections.
Some of the cells can be expanded, by press a button in the cell.
The button is an arrow like ">" but pointing to the bottom , when pressed it should become up side down and the cell expand. Press it again the arrow point to bottom again and the cell shrink.I want to add an animation to it .
Animation
extension UIView{
func addAnimation_rotation_x (from : Double , to : Double){
let rotationAnimation = CABasicAnimation()
rotationAnimation.keyPath = "transform.rotation.x"
rotationAnimation.duration = 0.3
rotationAnimation.removedOnCompletion = false
rotationAnimation.fillMode = kCAFillModeForwards
rotationAnimation.fromValue = from
rotationAnimation.toValue = to
self.layer.addAnimation(rotationAnimation, forKey: nil)
}
}
ViewController
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
if index_of_expandedRow.contains(indexPath){
let height = CGFloat(self.total_dishArray[indexPath.section][indexPath.row].expanded_rows.count) * 60 + 150
return height
}else{
return 150
}
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCellWithIdentifier("DishTableViewCell") as! DishTableViewCell
if isFinishedLoadingDishes{
//setting cells
cell.btn_expand.addTarget(self, action: #selector(OrderViewController.expand(_:)), forControlEvents: UIControlEvents.TouchUpInside)
if index_of_expandedRow.contains(indexPath){
cell.btn_expand.addAnimation_rotation_y(0, to: M_PI)
}else{
cell.btn_expand.addAnimation_rotation_y(M_PI, to: 0)
}
}
return cell
}
func expand (sender :UIButton){
let cell = sender.superview!.superview as! UITableViewCell
let indexpath = tableView_right.indexPathForCell(cell)!
if self.index_of_expandedRow.contains(indexpath){
let index = self.index_of_expandedRow.indexOf(indexpath)!
self.index_of_expandedRow.removeAtIndex(index)
}else{
self.index_of_expandedRow.append(indexpath)
}
tableView_right.reloadRowsAtIndexPaths([indexpath], withRowAnimation: UITableViewRowAnimation.None)
//if the expanded content is not visible then make it visible
let frame = self.tableView_right.cellForRowAtIndexPath(indexpath)!.frame
if frame.origin.y + frame.height > tableView_right.frame.height + tableView_right.contentOffset.y {
tableView_right.setContentOffset(CGPointMake(0, tableView_right.contentOffset.y + ((frame.origin.y + frame.height) - (tableView_right.frame.height + tableView_right.contentOffset.y))) ,animated: true)
}
}
I expand the rows by changing their height.
The animation worked well when hitting the button the first time , but failed after.
Any suggestion would be appreciated.
I have a _TableView with items , and I want to set automatic refresh,and I don't want it to scroll on refresh , lets say user scrolled 2 pages down , and the refresh trigered -> so I want to put the refreshed content to the top of the table without interupting user's scrolling
Assume user was on row 18
and now the _dataSource is refreshed so it fetched lets say 4 items , so I want user to stay on the item he was.
What would be the best approach to achieve it ??
For Swift 3+:
You need to save the current offset of the UITableView, then reload and then set the offset back on the UITableView.
I have created this function for this purpose:
func reload(tableView: UITableView) {
let contentOffset = tableView.contentOffset
tableView.reloadData()
tableView.layoutIfNeeded()
tableView.setContentOffset(contentOffset, animated: false)
}
Simply call it with: reload(tableView: self.tableView)
SWIFT 3
let contentOffset = self.tableView.contentOffset
self.tableView.reloadData()
self.tableView.layoutIfNeeded()
self.tableView.setContentOffset(contentOffset, animated: false)
This is error of iOS8 when using UITableViewAutomatic Dimension. We need store the content offset of table, reload table, force layout and set contenOffset back.
CGPoint contentOffset = self.tableView.contentOffset;
[self.tableView reloadData];
[self.tableView layoutIfNeeded];
[self.tableView setContentOffset:contentOffset];
I am showing if only one row is being added. You can extend it to multiple rows.
// dataArray is your data Source object
[dataArray insertObject:name atIndex:0];
CGPoint contentOffset = self.tableView.contentOffset;
contentOffset.y += [self tableView:self.tableView heightForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]];
[self.tableView reloadData];
[self.tableView setContentOffset:contentOffset];
But for this to work you need to have defined - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath the method. Or else, you can directly give your tableview row height if it is constant.
Just set estimatedRowHeight to maximum possible value.
self.tableView.estimatedRowHeight = 1000
self.tableView.estimatedSectionFooterHeight = 100.0
self.tableView.estimatedSectionHeaderHeight = 500.0
That's it!!
Note:
Please do not use FLT_MAX, DBL_MAX value. May be it will crash your app.
I'm doing it this way:
messages.insertContentsOf(incomingMsgs.reverse(), at: 0)
table.reloadData()
// This is for the first load, first 20 messages, scroll to bottom
if (messages.count <= 20) {
let indexToScroll = NSIndexPath(forRow: saferSelf.messages.count - 1, inSection: 0)
table.scrollToRowAtIndexPath(indexToScroll, atScrollPosition: .Top , animated: false)
}
// This is to reload older messages on top of tableview
else {
let indexToScroll = NSIndexPath(forRow: incomingMsgs.count, inSection: 0)
table.scrollToRowAtIndexPath(indexToScroll, atScrollPosition: .Top , animated: false)
// Remove the refreshControl.height + tableHeader.height from the offset so the content remain where it was before reload
let theRightOffset = CGPointMake(0, table.contentOffset.y - refreshControl.frame.height - table.headeView.frame.height)
table.setContentOffset(theRightOffset, animated: false)
}
...also, since I use dynamic cell height, to avoid some weirdness, the estimation is cached:
var heightAtIndexPath = [NSIndexPath: CGFloat]()
func tableView(tableView: UITableView, estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return heightAtIndexPath[indexPath] ?? UITableViewAutomaticDimension
}
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
heightAtIndexPath[indexPath] = cell.frame.height
}
Use Extension
create UITableViewExtensions.swift and add following:
extension UITableView {
func reloadDataWithoutScroll() {
let offset = contentOffset
reloadData()
layoutIfNeeded()
setContentOffset(offset, animated: false)
}
}
In iOS 12.x, using Xcode 10.2.1, an easier option is.
UIView.performWithoutAnimation {
let loc = tableView.contentOffset
tableView.reloadRows(at: [indexPath], with: .none)
tableView.contentOffset = loc
}
This works better than following; it shakes at times when the row is not fully visible.
let contentOffset = self.tableView.contentOffset
self.tableView.reloadData()
self.tableView.layoutIfNeeded()
self.tableView.setContentOffset(contentOffset, animated: false)
Swift 4.2 : Simple Solution
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.estimatedRowHeight = 0
self.tableView.estimatedSectionHeaderHeight = 0
self.tableView.estimatedSectionFooterHeight = 0
}
//And then simply update(insert, reloadSections, delete etc) your tableView or reload
tableView.reloadData()
//or
UIView.performWithoutAnimation {
tableView.beginUpdates()
.....
tableView.endUpdates()
}
This code will prevent unnecessary animation and maintain the scroll view's content offset, it worked fine for me.
let lastScrollOffset = tableView.contentOffset
tableView.beginUpdates()
tableView.reloadData()
tableView.endUpdates()
tableView.layer.removeAllAnimations()
tableView.setContentOffset(lastScrollOffset, animated: false)
When you want to reload you have to
self.tableView.reloadData()
self.tableView.layoutIfNeeded()
and also use this UITableViewDelegate
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return 'your maximum cell's height'
}
and your tableView will remain on the previous scroll position without scrolling
try to replace
reloadData with
tableView.reloadRows(at: tableView!.indexPathsForVisibleRows!, with: .none),
but you should be care about no cells, if no cells, this method should cause crash.
i wrote something that works perfect for me:
extension UIScrollView {
func reloadDataAndKeepContentOffsetInPlace(reloadData:(() -> Void)) {
let currentContentHeight = contentSize.height
if currentContentHeight == .zero {
reloadData()
return
}
reloadData()
layoutIfNeeded()
let newContentHeight = self.contentSize.height
DispatchQueue.main.async {
var contentOffset = self.contentOffset
contentOffset.y += newContentHeight - currentContentHeight
self.setContentOffset(contentOffset, animated: false)
}
}
}
use like this:
self.reloadSomeData()
collectionView.reloadDataAndKeepContentOffsetInPlace { [weak self] in
guard let self = self else { return }
self.collectionView.reloadData()
}
Try the following.
tableView.estimatedRowHeight = 0
tableView.estimatedSectionHeaderHeight = 0
tableView.estimatedSectionFooterHeight = 0
Source: https://developer.apple.com/forums/thread/86703
By default (i.e., with a vertical scrolling direction), the UICollectionViewFlowLayout lays out cells by starting at the top-left, going from left to right, until the row is filled, and then proceeds to the next line down. Instead, I would like it to start at the bottom-left, go from left to right, until the row is filled, and then proceed to the next line up.
Is there a straightforward way to do this by subclassing UIScrollViewFlowLayout, or do I basically need to re-implement that class from scratch?
Apple's documentation on subclassing flow layout suggests that I only need to override and re-implement my own version of layoutAttributesForElementsInRect:, layoutAttributesForItemAtIndexPath:, and collectionViewContentSize. But this does not seem straightforward. Since UICollectionViewFlowLayout does not expose any of the grid layout calculations it makes internally in prepareLayout, I need to deduce all the layout values needed for the bottom-to-top layout from the values it generates for a top-to-bottom layout.
I am not sure this is possible. While I can re-use its calculations about which groups of items get put on the same rows, I will need to calculate new y offsets. And to make my calculations I will need information about all the items, but those superclass methods do not report that.
The very helpful answer by #insane-36 showed a way to do it when collectionView.bounds == collectionView.collectionViewContentSize.
But if you wish to support the case where collectionView.bounds < collectionViewcontentSize, then I believe you need to re-map the rects exactly to support scrolling properly. If you wish to support the case where collectionView.bounds > collectionViewContentSize, then you need to override collectionViewContentSize to ensure the content rect is positioned at the bottom of the collectionView (since otherwise it will be positioned at the top, due to the top-to-bottom default behavior of UIScrollView).
So the full solution is a bit more involved, and I ended up developing it here: https://github.com/algal/ALGReversedFlowLayout.
You could basically implement it with a simple logic, however this seems to be some how odd. If the collectionview contentsize is same as that of the collectionview bounds or if all the cells are visible then you could implement this with simple flowLayout as this,
#implementation SimpleFlowLayout
- (UICollectionViewLayoutAttributes*)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewLayoutAttributes *attribute = [super layoutAttributesForItemAtIndexPath:indexPath];
[self modifyLayoutAttribute:attribute];
return attribute;
}
- (NSArray*)layoutAttributesForElementsInRect:(CGRect)rect{
NSArray *attributes = [super layoutAttributesForElementsInRect:rect];
for(UICollectionViewLayoutAttributes *attribute in attributes){
[self modifyLayoutAttribute:attribute];
}
return attributes;
}
- (void)modifyLayoutAttribute:(UICollectionViewLayoutAttributes*)attribute{
CGSize contentSize = self.collectionViewContentSize;
CGRect frame = attribute.frame;
frame.origin.x = contentSize.width - attribute.frame.origin.x - attribute.frame.size.width;
frame.origin.y = contentSize.height - attribute.frame.origin.y - attribute.frame.size.height;
attribute.frame = frame;
}
#end
And so the figure looks like this,
But, if you use more rows, more than the that can be seen on the screen at the same time, then there seems to be some problem with reusing. Since the UICollectionView datasource method, collectionView:cellForItemAtIndexPath: works linearly and asks for the indexPath as the user scrolls, the cell are asked in the usual increasing indexPath pattern such as 1 --- 100 though we would want it to reverse this pattern. While scrolling we would need the collectionView to ask us for the items in decreasing order since our 100 item resides at top and 1 item at bottom. So, I dont have any particular idea about how this could be accomplished.
UICollectionView with a reversed flow layout.
import Foundation
import UIKit
class InvertedFlowLayout: UICollectionViewFlowLayout {
override func prepare() {
super.prepare()
}
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
guard super.layoutAttributesForElements(in: rect) != nil else { return nil }
var attributesArrayNew = [UICollectionViewLayoutAttributes]()
if let collectionView = self.collectionView {
for section in 0 ..< collectionView.numberOfSections {
for item in 0 ..< collectionView.numberOfItems(inSection: section) {
let indexPathCurrent = IndexPath(item: item, section: section)
if let attributeCell = layoutAttributesForItem(at: indexPathCurrent) {
if attributeCell.frame.intersects(rect) {
attributesArrayNew.append(attributeCell)
}
}
}
}
for section in 0 ..< collectionView.numberOfSections {
let indexPathCurrent = IndexPath(item: 0, section: section)
if let attributeKind = layoutAttributesForSupplementaryView(ofKind: UICollectionView.elementKindSectionHeader, at: indexPathCurrent) {
attributesArrayNew.append(attributeKind)
}
}
}
return attributesArrayNew
}
override func layoutAttributesForSupplementaryView(ofKind elementKind: String, at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
let attributeKind = UICollectionViewLayoutAttributes(forSupplementaryViewOfKind: elementKind, with: indexPath)
if let collectionView = self.collectionView {
var fullHeight: CGFloat = 0.0
for section in 0 ..< indexPath.section + 1 {
for item in 0 ..< collectionView.numberOfItems(inSection: section) {
let indexPathCurrent = IndexPath(item: item, section: section)
fullHeight += cellHeight(indexPathCurrent) + minimumLineSpacing
}
}
attributeKind.frame = CGRect(x: 0, y: collectionViewContentSize.height - fullHeight - CGFloat(indexPath.section + 1) * headerHeight(indexPath.section) - sectionInset.bottom + minimumLineSpacing/2, width: collectionViewContentSize.width, height: headerHeight(indexPath.section))
}
return attributeKind
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
let attributeCell = UICollectionViewLayoutAttributes(forCellWith: indexPath)
if let collectionView = self.collectionView {
var fullHeight: CGFloat = 0.0
for section in 0 ..< indexPath.section + 1 {
for item in 0 ..< collectionView.numberOfItems(inSection: section) {
let indexPathCurrent = IndexPath(item: item, section: section)
fullHeight += cellHeight(indexPathCurrent) + minimumLineSpacing
if section == indexPath.section && item == indexPath.item {
break
}
}
}
attributeCell.frame = CGRect(x: 0, y: collectionViewContentSize.height - fullHeight + minimumLineSpacing - CGFloat(indexPath.section) * headerHeight(indexPath.section) - sectionInset.bottom, width: collectionViewContentSize.width, height: cellHeight(indexPath) )
}
return attributeCell
}
override var collectionViewContentSize: CGSize {
get {
var height: CGFloat = 0.0
var bounds = CGRect.zero
if let collectionView = self.collectionView {
for section in 0 ..< collectionView.numberOfSections {
for item in 0 ..< collectionView.numberOfItems(inSection: section) {
let indexPathCurrent = IndexPath(item: item, section: section)
height += cellHeight(indexPathCurrent) + minimumLineSpacing
}
}
height += sectionInset.bottom + CGFloat(collectionView.numberOfSections) * headerHeight(0)
bounds = collectionView.bounds
}
return CGSize(width: bounds.width, height: max(height, bounds.height))
}
}
override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
if let oldBounds = self.collectionView?.bounds,
oldBounds.width != newBounds.width || oldBounds.height != newBounds.height {
return true
}
return false
}
func cellHeight(_ indexPath: IndexPath) -> CGFloat {
if let collectionView = self.collectionView, let delegateFlowLayout = collectionView.delegate as? UICollectionViewDelegateFlowLayout {
let size = delegateFlowLayout.collectionView!(collectionView, layout: self, sizeForItemAt: indexPath)
return size.height
}
return 0
}
func headerHeight(_ section: Int) -> CGFloat {
if let collectionView = self.collectionView, let delegateFlowLayout = collectionView.delegate as? UICollectionViewDelegateFlowLayout {
let size = delegateFlowLayout.collectionView!(collectionView, layout: self, referenceSizeForHeaderInSection: section)
return size.height
}
return 0
}
}