I have setup a tableview with dynamic height cells aka UITableView.automaticDimension using Autolayout. This works fine. Now what I am trying to achieve is to change the height of cell & animate it. The issue is that when I change cell height & animate it, the animation is weirdly jumping. The jump only occurs if I scroll down a bit & then expand/collapse cells.
I have a simple table view cell. It has a label & an empty UIView with fixed height constraint. When I want to collapse/expand the cell, I simply change the constant of that height constraint to 0 or 300.
I have tried many collapsable tableview examples off the internet. All of them have this issue. One exception is https://github.com/Ramotion/folding-cell, but that uses fixed heights for cells.
I have tried quite a few options to animate the cell height change.
1-> On didSelectRow, I change the height constraint & call tableview beginUpdate & endUpdates. Doesn't solve the jump issue.
2-> Change my model & call tableView.reloadRows. Doesn't solve the jump issue.
This is screenshot of my tableview cell setup.
https://drive.google.com/open?id=12nba6cwRszxRlaSA-IhrX3X_vLZ4AWxy
A link to video of this issue:
https://drive.google.com/open?id=19Xmc0PMXT0EuHTJeeGHm4M5aPoChAtf3
override func viewDidLoad() {
super.viewDidLoad()
tableView.dataSource = self
tableView.delegate = self
tableView.estimatedRowHeight = 50
tableView.rowHeight = UITableView.automaticDimension
tableView.estimatedSectionHeaderHeight = 0
tableView.estimatedSectionFooterHeight = 0
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! OuterTableViewCell
let height: CGFloat = isCellExpanded[indexPath.row] ? 300 : 0
cell.labelText.text = "Cell Number: \(indexPath.row + 1)"
cell.buttonExpansionToggle.setImage(UIImage(named: isCellExpanded[indexPath.row] ? "arrow-down" : "arrow-right"),
for: .normal)
cell.viewContainerHeight.constant = height
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
isCellExpanded[indexPath.row] = !isCellExpanded[indexPath.row]
tableView.reloadRows(at: [indexPath], with: .automatic)
}
Another form of didSelectRow:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
guard let cell = tableView.cellForRow(at: indexPath) as? OuterTableViewCell else { return }
isCellExpanded[indexPath.row] = !isCellExpanded[indexPath.row]
let height: CGFloat = self.isCellExpanded[indexPath.row] ? 300 : 0
cell.viewContainerHeight.constant = height
cell.layoutIfNeeded()
UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseOut, animations: {
tableView.beginUpdates()
tableView.endUpdates()
// fix https://github.com/Ramotion/folding-cell/issues/169
if cell.frame.maxY > tableView.frame.maxY {
tableView.scrollToRow(at: indexPath, at: UITableView.ScrollPosition.bottom, animated: true)
}
}, completion: nil)
}
I have also tried to call beginUpdates() & endUpdates() outside animation block, yet the issue persists.
I expect the animation to be smooth. Hope someone can help. If someone can setup a simple demo project on github that would be awesome.
Demo project link: https://gitlab.com/FahadMasoodP/nested-tableviews
Help in any form is appreciated. Thanks.
My solution is adding dynamic estimate row height. I think it is bug of UIKit. iOS 13 issue will be not occur.
First, You need add property estimateRowHeightStorage to store estimate height by indexpath
var estimateRowHeightStorage: [IndexPath:CGFloat] = [:]
Second, You need store current height of cell for use later
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
estimateRowHeightStorage[indexPath] = cell.frame.size.height
}
Final, you use estimateRowHeightStorage to set estimate row height.
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
if estimateRowHeightStorage[indexPath] != nil {
return estimateRowHeightStorage[indexPath]!
}
return 50
}
Run and feel.
I did found new solution in your case. If you hardfix height when expand. Only need change some thing.
Replace all code above with estimatedHeightForRowAt function
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
let height: CGFloat = isCellExpanded[indexPath.row] ? 373 : 73
return height
}
How to update tableview cell height after updating image height constraint of image downloaded async?
How to trigger tableView cell relayout after image downloaded and constraints changed?
What's the best method to do this?
Already tried putting the code inside Dispatch main queue, but same bad results. I'm doing this in cellForRow method, also moved it to willDisplayCell. Again and again this problem...
Example of code using Kingfisher library for image caching:
if let imgLink = post.imageLink {
if let url = URL(string: imgLink) {
cell.postImage.kf.setImage(with: url, placeholder: UIImage(), options: nil, progressBlock: nil) { (image, error, cacheType, imageURL) in
if let image = image, cell.tag == indexPath.row {
cell.heightConstraint.constant = image.size.height * cell.frame.size.width / image.size.width
}
}
}
}
You may try to call these 2 lines to cause cell heights be recalculated after an image becomes available:
tableView.beginUpdates()
tableView.endUpdates()
See in the documentation https://developer.apple.com/documentation/uikit/uitableview/1614908-beginupdates: "You can also use this method followed by the endUpdates() method to animate the change in the row heights without reloading the cell."
IMHO, As ppalancica pointed out calling beginUpdates and endUpdates is the ideal way. You can't refer tableView from inside UITableViewCell and the proper way is to use a delegate and call beginUpdates and endUpdates from ViewController implementing delegate.
Delegate:
protocol ImageCellDelegate {
func onLayoutChangeNeeded()
}
UITableViewCell implementation:
class ImageCell: UITableViewCell {
var imageView: UIImageView = ...
var delegate: ImageCellDelegate?
...
func setImage(image: UIImage) {
imageView.image = image
//calling delegate implemented in 'ViewController'
delegate?.onLayoutChangeNeeded()
}
...
}
ViewController Implementation:
class ViewController: UIViewController, UITableViewDataSource, ImageCellDelegate {
var tableView: UITableView = ...
.....
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let imageCell = tableView.dequeueReusableCell(withIdentifier: id, for: indexPath) as! ImageCell
//setting 'delegate' here
imageCell.delegate = self
return imageCell
}
//called from 'ImageCell' when 'image' is set inside 'setImage'
func onLayoutChangeNeeded() {
tableView.beginUpdates()
tableView.endUpdates()
}
.....
}
I had the same problem. What you need to remember is Tableview reuse the cell and you are loading image async.
Recommended: You can do is to request your backhand team to provide you height and width of image so you can calculate cell height and return asap.
If you can't do that you can keep size of dowloaded image in your datasource. so before you download image check your datasource for size of image and update height constraint constant.
Another thing is you should do it in both cellForRow and willDisplay cell (I know it is not good practice but to satisfy tableview automatic dimension)
after update height constant you should use this pair of code to reload your cell.
cell.setNeedsLayout()
cell.layoutIfNeeded()
How I did
if let imagesize = post.imageSize {
cell.updateHeightPerRatio(with: imagesize)
} else {
// Here load size from URL and update your datasource
}
// Load image from URL with any SDWebimage or any other library you used
What I actually did and worked somehow is the following:
if (self.firstLoaded[indexPath.row] == false) {
self.firstLoaded[indexPath.row] = true
DispatchQueue.main.async {
self.tableViewController.tableView.reloadData()
}
}
firstLoaded just tells the table that this row has already received image from URL and calculated / stored correct height.
Also, I used this:
override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
cellHeights[indexPath] = cell.frame.size.height
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
override func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
if let height = cellHeights[indexPath] {
return height
}
return 1500
}
I know that calling reloadData() is not a good practice, but it solved my problem. If anybody has some other advices, please do not hesitate to share it.
Thanks!
I have a table view cell. I make an app for a tenant in the apartment to report the defect of the room facility. if the defect has been repaired (status: Complete), data from server will give defect.status == 2 (if defect.status == 1, still on process to be repaired), and it will show YES and NO Button like the picture above.
I want if it still on the repairment process, the view that contains "Are You satisfied" label and Yes No Button will not appear. The expected result should be like the picture below
here is the code I use to remove that satisfied or not view
extension RequestDefectVC : UITableViewDataSource {
//MARK: Table View Delegate & Datasource
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return listDefects.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.removeFromSuperview()
}
}
return cell
}
}
but unfortunately, if that wantToRemoveView.removeFromSuperview() is triggered, it will remove all the view in all cell, even though the status is completed like picture below
I want that satisfied or not view appears if the status is complete, otherwise, it will be removed. how to do that ?
For your costumed cells are reused, removing views will cause uncertain effects. You don't actually need the specific view to be removed, only if it stays invisible.
if dataDefect.status == 2 {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.isHidden = true
}
} else {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.isHidden = false
}
}
Create a height constraint for that view and hook it as IBOutlet and control it's constant according to that in cellForRowAt
self.askViewH.constant = show ? 50 : 0
cell.layoutIfNeeded()
return cell
I expect you using automatic tableView cells
#Alexa289 One suggestion is that you can take heightConstraints of UIView. then create IBOutlet of your height constraints and make its constant 0 when you want to hide otherwise assign value to your static height.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
cell.viewSatisficationHeightConstraints.constant = 50
} else {
cell.viewSatisficationHeightConstraints.constant = 0
}
return cell
}
Second suggestion is that you can take label and button in view and embed stackview to your view(view contain label and button)
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
cell.viewSatisfication.isHidden = false
} else {
cell.viewSatisfication.isHidden = true
}
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
override func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return 40
}
you can read about UIStackView which makes hiding things easier. If you are not using stackview and hiding things the UI will not good as the space used by the hidden view will be still there. So better to use stackView when need to hide or show some view.
UIStackView : https://developer.apple.com/documentation/uikit/uistackview
I'm having some height problems with my dynamic UITableViewCell (sew picture below). Some cells have the correct height and some not, and when I drag the tableView some of the cells become correct and some don't.
I'm using this code to get the cell's height to be dynamic and reloading it in viewDidAppear and viewDidLoad.
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = tableView.rowHeight
As mentioned the cells are sometimes correct and sometimes not. Is there another way to do it or am I doing something wrong? I have tried many different solutions, all mentioned here as well as other suggestions both here at StackOverflow and other sites.
I appreciate all help!
Edit!
TableView
extension ChatVC: UITableViewDelegate, UITableViewDataSource {
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return groupMessages.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: "groupFeedCell", for: indexPath) as? GroupFeedCell else { return UITableViewCell() }
let message = groupMessages[indexPath.row]
DataService.instance.getUsername(forUID: message.senderId, handler: { (name) in
cell.configureCell(name: name, content: message.content)
})
cell.layoutSubviews()
cell.layoutIfNeeded()
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return 66
}
}
Cell
#IBOutlet weak var nameLbl: UILabel!
#IBOutlet weak var contentLbl: UILabel!
func configureCell(name: String, content: String) {
self.nameLbl.text = name //email
self.contentLbl.text = content
}
For dynamic tableViewCell
1- Setup this 2 lines with an inital value for the row height to help autolayout drawing it (take it from current cell height in the nib file)
tableView.rowHeight = UITableViewAutomaticDimension;
tableView.estimatedRowHeight = number;
2- don't implement this function heightForRowAtIndexPath . or implement it and return this
return UITableViewDynamicHeight;
3- make sure all constraints in the cell nib file or in storyboard are hooked correctly from top to bottom.
4- in cellForRowAtIndexPath before the line retrun cell insert that
[cell layoutSubviews];
[cell layoutIfneeded];
5- Test in simulator some versions like ios 8 it's a bug also in the viewController call
[tableView LayouSubviews];
in viewdidLayoutSubViews function to re relayout again correctly
6- Make lines property of any UILabel that you want to wrap = 0 and hook it's leading and trailing constarints to superView
Your are facing this issue because the content of your label comes from an async function.
The cell uses its content to work out its height dynamically. When your async request returns it has already done its work and will not recalculate and resize.
You need to make these requests, cache/store the results and reload the cells as needed. Usually in chat there would only be a couple of users to load usernames for anyway. You could also try pre-loading this data before the chat is displayed.
You can quickly confirm this by creating an array of random usernames and messages (sample data) and adding that to the cell straight away.
I guess the problem is asynchronous function. So Should you try
Step 1: Create names array
var names: [String?] = Array<String>.init(repeating: nil, count: groupMessages.count)
Step 2: Replace
DataService.instance.getUsername(forUID: message.senderId, handler: { (name) in
cell.configureCell(name: name, content: message.content)
})
By
if names[indexPath.row] == nil {
DataService.instance.getUsername(forUID: message.senderId, handler: { (name) in
names[indexPath.row] = name
tableView.reloadRows(at: [indexPath], with: .automatic)
})
} else {
cell.configureCell(name: name, content: message.content)
}
I feel like this might be a common issue and was wondering if there was any common solution to it.
Basically, my UITableView has dynamic cell heights for every cell. If I am not at the top of the UITableView and I tableView.reloadData(), scrolling up becomes jumpy.
I believe this is due to the fact that because I reloaded data, as I'm scrolling up, the UITableView is recalculating the height for each cell coming into visibility. How do I mitigate that, or how do I only reloadData from a certain IndexPath to the end of the UITableView?
Further, when I do manage to scroll all the way to the top, I can scroll back down and then up, no problem with no jumping. This is most likely because the UITableViewCell heights were already calculated.
To prevent jumping you should save heights of cells when they loads and give exact value in tableView:estimatedHeightForRowAtIndexPath:
Swift:
var cellHeights = [IndexPath: CGFloat]()
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
cellHeights[indexPath] = cell.frame.size.height
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return cellHeights[indexPath] ?? UITableView.automaticDimension
}
Objective C:
// declare cellHeightsDictionary
NSMutableDictionary *cellHeightsDictionary = #{}.mutableCopy;
// declare table dynamic row height and create correct constraints in cells
tableView.rowHeight = UITableViewAutomaticDimension;
// save height
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
[cellHeightsDictionary setObject:#(cell.frame.size.height) forKey:indexPath];
}
// give exact height value
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath {
NSNumber *height = [cellHeightsDictionary objectForKey:indexPath];
if (height) return height.doubleValue;
return UITableViewAutomaticDimension;
}
Swift 3 version of accepted answer.
var cellHeights: [IndexPath : CGFloat] = [:]
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
cellHeights[indexPath] = cell.frame.size.height
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return cellHeights[indexPath] ?? 70.0
}
The jump is because of a bad estimated height. The more the estimatedRowHeight differs from the actual height the more the table may jump when it is reloaded especially the further down it has been scrolled. This is because the table's estimated size radically differs from its actual size, forcing the table to adjust its content size and offset.
So the estimated height shouldn't be a random value but close to what you think the height is going to be. I have also experienced when i set UITableViewAutomaticDimension
if your cells are same type then
func viewDidLoad() {
super.viewDidLoad()
tableView.estimatedRowHeight = 100//close to your cell height
}
if you have variety of cells in different sections then I think the better place is
func tableView(tableView: UITableView, estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
//return different sizes for different cells if you need to
return 100
}
#Igor answer is working fine in this case, Swift-4 code of it.
// declaration & initialization
var cellHeightsDictionary: [IndexPath: CGFloat] = [:]
in following methods of UITableViewDelegate
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
// print("Cell height: \(cell.frame.size.height)")
self.cellHeightsDictionary[indexPath] = cell.frame.size.height
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
if let height = self.cellHeightsDictionary[indexPath] {
return height
}
return UITableView.automaticDimension
}
I have tried all the workarounds above, but nothing worked.
After spending hours and going through all the possible frustrations, figured out a way to fix this. This solution is a life savior! Worked like a charm!
Swift 4
let lastContentOffset = tableView.contentOffset
tableView.beginUpdates()
tableView.endUpdates()
tableView.layer.removeAllAnimations()
tableView.setContentOffset(lastContentOffset, animated: false)
I added it as an extension, to make the code look cleaner and avoid writing all these lines every time I want to reload.
extension UITableView {
func reloadWithoutAnimation() {
let lastScrollOffset = contentOffset
beginUpdates()
endUpdates()
layer.removeAllAnimations()
setContentOffset(lastScrollOffset, animated: false)
}
}
finally ..
tableView.reloadWithoutAnimation()
OR you could actually add these line in your UITableViewCell awakeFromNib() method
layer.shouldRasterize = true
layer.rasterizationScale = UIScreen.main.scale
and do normal reloadData()
I use more ways how to fix it:
For view controller:
var cellHeights: [IndexPath : CGFloat] = [:]
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
cellHeights[indexPath] = cell.frame.size.height
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return cellHeights[indexPath] ?? 70.0
}
as the extension for UITableView
extension UITableView {
func reloadSectionWithoutAnimation(section: Int) {
UIView.performWithoutAnimation {
let offset = self.contentOffset
self.reloadSections(IndexSet(integer: section), with: .none)
self.contentOffset = offset
}
}
}
The result is
tableView.reloadSectionWithoutAnimation(section: indexPath.section)
I ran into this today and observed:
It's iOS 8 only, indeed.
Overridding cellForRowAtIndexPath doesn't help.
The fix was actually pretty simple:
Override estimatedHeightForRowAtIndexPath and make sure it returns the correct values.
With this, all weird jittering and jumping around in my UITableViews has stopped.
NOTE: I actually know the size of my cells. There are only two possible values. If your cells are truly variable-sized, then you might want to cache the cell.bounds.size.height from tableView:willDisplayCell:forRowAtIndexPath:
You can in fact reload only certain rows by using reloadRowsAtIndexPaths, ex:
tableView.reloadRowsAtIndexPaths(indexPathArray, withRowAnimation: UITableViewRowAnimation.None)
But, in general, you could also animate table cell height changes like so:
tableView.beginUpdates()
tableView.endUpdates()
Overriding the estimatedHeightForRowAtIndexPath method with an high value, for example 300f
This should fix the problem :)
Here's a bit shorter version:
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return self.cellHeightsDictionary[indexPath] ?? UITableViewAutomaticDimension
}
There is a bug which I believe was introduced in iOS11.
That is when you do a reload the tableView contentOffSet gets unexpectedly altered. In fact contentOffset should not change after a reload. It tends to happen due to miscalculations of UITableViewAutomaticDimension
You have to save your contentOffSet and set it back to your saved value after your reload is finished.
func reloadTableOnMain(with offset: CGPoint = CGPoint.zero){
DispatchQueue.main.async { [weak self] () in
self?.tableView.reloadData()
self?.tableView.layoutIfNeeded()
self?.tableView.contentOffset = offset
}
}
How you use it?
someFunctionThatMakesChangesToYourDatasource()
let offset = tableview.contentOffset
reloadTableOnMain(with: offset)
This answer was derived from here
This one worked for me in Swift4:
extension UITableView {
func reloadWithoutAnimation() {
let lastScrollOffset = contentOffset
reloadData()
layoutIfNeeded()
setContentOffset(lastScrollOffset, animated: false)
}
}
One of the approach to solve this problem that I found is
CATransaction.begin()
UIView.setAnimationsEnabled(false)
CATransaction.setCompletionBlock {
UIView.setAnimationsEnabled(true)
}
tableView.reloadSections([indexPath.section], with: .none)
CATransaction.commit()
None of these solutions worked for me. Here's what I did with Swift 4 & Xcode 10.1...
In viewDidLoad(), declare table dynamic row height and create correct constraints in cells...
tableView.rowHeight = UITableView.automaticDimension
Also in viewDidLoad(), register all your tableView cell nibs to tableview like this:
tableView.register(UINib(nibName: "YourTableViewCell", bundle: nil), forCellReuseIdentifier: "YourTableViewCell")
tableView.register(UINib(nibName: "YourSecondTableViewCell", bundle: nil), forCellReuseIdentifier: "YourSecondTableViewCell")
tableView.register(UINib(nibName: "YourThirdTableViewCell", bundle: nil), forCellReuseIdentifier: "YourThirdTableViewCell")
In tableView heightForRowAt, return height equal to each cell's height at indexPath.row...
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if indexPath.row == 0 {
let cell = Bundle.main.loadNibNamed("YourTableViewCell", owner: self, options: nil)?.first as! YourTableViewCell
return cell.layer.frame.height
} else if indexPath.row == 1 {
let cell = Bundle.main.loadNibNamed("YourSecondTableViewCell", owner: self, options: nil)?.first as! YourSecondTableViewCell
return cell.layer.frame.height
} else {
let cell = Bundle.main.loadNibNamed("YourThirdTableViewCell", owner: self, options: nil)?.first as! YourThirdTableViewCell
return cell.layer.frame.height
}
}
Now give an estimated row height for each cell in tableView estimatedHeightForRowAt. Be accurate as you can...
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
if indexPath.row == 0 {
return 400 // or whatever YourTableViewCell's height is
} else if indexPath.row == 1 {
return 231 // or whatever YourSecondTableViewCell's height is
} else {
return 216 // or whatever YourThirdTableViewCell's height is
}
}
That should work...
I didn't need to save and set contentOffset when calling tableView.reloadData()
I have 2 different cell heights.
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
let cellHeight = CGFloat(checkIsCleanResultSection(index: indexPath.row) ? 130 : 160)
return Helper.makeDeviceSpecificCommonSize(cellHeight)
}
After I added estimatedHeightForRowAt, there was no more jumping.
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
let cellHeight = CGFloat(checkIsCleanResultSection(index: indexPath.row) ? 130 : 160)
return Helper.makeDeviceSpecificCommonSize(cellHeight)
}
For me the working solution is
UIView.setAnimationsEnabled(false)
tableView.performBatchUpdates { [weak self] in
self?.tableView.reloadRows(at: [indexPath], with: .none)
} completion: { [weak self] _ in
UIView.setAnimationsEnabled(true)
self?.tableView.scrollToRow(at: indexPath, at: .top, animated: true) // remove if you don't need to scroll
}
I have expandable cells.
Try to call cell.layoutSubviews() before returning cell in func cellForRowAtIndexPath(_ indexPath: NSIndexPath) -> UITableViewCell?. It's known bug in iOS8.
You can use the following in ViewDidLoad()
tableView.estimatedRowHeight = 0 // if have just tableViewCells <br/>
// use this if you have tableview Header/footer <br/>
tableView.estimatedSectionFooterHeight = 0 <br/>
tableView.estimatedSectionHeaderHeight = 0
I had this jumping behavior and I initially was able to mitigate it by setting the exact estimated header height (because I only had 1 possible header view), however the jumps then started to happen inside the headers specifically, not affecting the whole table anymore.
Following the answers here, I had the clue that it was related to animations, so I found that the table view was inside a stack view, and sometimes we'd call stackView.layoutIfNeeded() inside an animation block. My final solution was to make sure this call doesn't happen unless "really" needed, because layout "if needed" had visual behaviors in that context even when "not needed".
I had the same issue. I had pagination and reloading data without animation but it did not help the scroll to prevent jumping. I have different size of IPhones, the scroll was not jumpy on iphone8 but it was jumpy on iphone7+
I applied following changes on viewDidLoad function:
self.myTableView.estimatedRowHeight = 0.0
self.myTableView.estimatedSectionFooterHeight = 0
self.myTableView.estimatedSectionHeaderHeight = 0
and my problem solved. I hope it helps you too.
For me, it worked with "heightForRowAt"
extension APICallURLSessionViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
print("Inside heightForRowAt")
return 130.50
}
}
Actually I found if you use reloadRows causing a jump problem. Then you should try to use reloadSections like this:
UIView.performWithoutAnimation {
tableView.reloadSections(NSIndexSet(index: indexPath.section) as IndexSet, with: .none)
}