UITableView content size while using auto-layout - ios

Question

I want to calculate Content size of my UITableView. I am using autolayout with height UITableViewAutomaticDimension.
Tried to get [UITableView contentsize] after reloading tableview, in that case height get calculated based on estimatedRowHeight.
self.tableView.estimatedRowHeight = 50;
self.tableView.rowHeight = UITableViewAutomaticDimension;
Delegate -
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
    return UITableViewAutomaticDimension;
}
Trying to get content size and assign it to height constrain.
[self.tableView reloadData];
[self.tableView layoutIfNeeded];
self.tableHeightConstraint.constant = self.tableView.contentSize.height;
Any suggestions? Thanks in advance.
Edit:
Finally I am solved my problem with some tweak. I changed tableview height to max (In my case 300 is max) before reloading data on table, so tableview has space to resize all cells.
self.tableHeightConstraint.constant = 300;
[self.tableView reloadData];
[self.tableView layoutIfNeeded];
self.tableHeightConstraint.constant = self.tableView.contentSize.height;
Thanks for help.

Answer 1

Finally I am solved my problem with some tweak. I changed tableview height to max (Objective-C: CGFLOAT_MAX, Swift: CGFloat.greatestFiniteMagnitude) before reloading data on table, so tableview has space to resize all cells.
Objective-C:
self.tableHeightConstraint.constant = CGFLOAT_MAX;
[self.tableView reloadData];
[self.tableView layoutIfNeeded];
self.tableHeightConstraint.constant = self.tableView.contentSize.height;
Swift:
tableHeightConstraint.constant = CGFloat.greatestFiniteMagnitude
tableView.reloadData()
tableView.layoutIfNeeded()
tableHeightConstraint.constant = contentTableView.contentSize.height
Posting this so it will be helpful for others.

Answer 2

Finally, I understood you problem and here is the solution of it.
I hope you have already done this.
First take put some fix height of UITableView.
Then take the constraint IBOutlet of UITableView Height.
Then under viewDidLayoutSubviews method you can get the original UITableView height after populating the data.
Update the below code:
override func viewDidLayoutSubviews() {
constTableViewHeight.constant = tableView.contentSize.height
}
Update:
self.tableView.estimatedRowHeight = UITableViewAutomaticDimension;
Please check this.

Answer 3

By setting the estimatedRowHeight to zero during table view initialisation and by adding the following code to viewDidLayoutSubviews worked for me!
tableView.reloadData()
tableView.layoutIfNeeded()
tableView.constant = tableView.contentSize.height

Answer 4

All the solutions above weren't working for my case.
I ended up using an observer like this:
self.tableView.addObserver(self, forKeyPath: "contentSize", options: .new, context: nil)
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
if let obj = object as? UITableView {
if obj == self.tableView && keyPath == "contentSize" {
if let newSize = change?[NSKeyValueChangeKey.newKey] as? CGSize {
self.tableView.frame.size.height = newSize.height
}
}
}
}

Answer 5

Using UICollectionView for custom cell size is the best solution for me but if you somehow prefer UITableView, you can use KVO instead.
Using KVO is the best practice to solve this contentSize problem, you don't need to use layoutIfNeeded to force the TableView to update its layout. Using #OnkarK answer (the accepted answer) will cause lag if the max_height (CGFloat.greatestFiniteMagnitude) is too big and setting the height manually is not a good idea.
Using Swift KVO:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.tableView.addObserver(self, forKeyPath: "contentSize", options: .new, context: nil)
}
override func viewWillDisappear(_ animated: Bool) {
self.tableView.removeObserver(self, forKeyPath: "contentSize")
super.viewWillDisappear(true)
}
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?){
if keyPath == "contentSize" {
if let value = change?[.newKey]{
let size = value as! CGSize
self.tableHeightConstraint.constant = size.height
}
}
}
Using Combine:
override func viewDidLoad() {
super.viewDidLoad()
tableView.publisher(for: \.contentSize)
.receive(on: RunLoop.main)
.sink { size in
self.tableHeightConstraint.constant = size.height
}.store(in: &cancellables)
}
Using RxSwift:
override func viewDidLoad() {
super.viewDidLoad()
tableView.rx.observe(CGSize.self, "contentSize")
.filter({$0 != nil})
.subscribe(onNext: { size in
self.tableHeightConstraint.constant = size!.height
}).disposed(by: bag)
}

Answer 6

for swift just use
tableView.invalidateIntrinsicContentSize()
tableView.layoutIfNeeded()
after reloadData()
and
tableView.contentSize.height
will works perfect.
Example on medium

Answer 7

You can try two things,
Call below method just after some seconds of delay after tableView reloads completely.
- (void)adjustHeightOfTableview
{
dispatch_async(dispatch_get_main_queue(), ^{
[self.tableView reloadData];
//In my case i had to call this method after some delay, because (i think) it will allow tableView to reload completely and then calculate the height required for itself. (This might be a workaround, but it worked for me)
[self performSelector:#selector(adjustHeightOfTableview) withObject:nil afterDelay:0.3];
});
}
When you call above method do not return estimatedHeightForRow,
/*
-(CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 44;
}
*/
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return UITableViewAutomaticDimension;
}
Just give it a try, it could help you get the problem.

Answer 8

For me the solution was to just set the estimatedRowHeight to a value larger than anything I deemed possible for the data I had to display.
For some reason this ensured that the estimatedRowHeight property wasn't used to determine the contentSize. I don't display the scroll indicator so it didn't really matter to me that the estimatedRowHeight was way off.

Answer 9

In my case, I don't use tableView's height constraint - using auto layout, top and bottom constraint is set and only bottom constraint changes as it goes into/out of edit mode.
Tzegenos's answer is modified in this way:
1. add tableView.estimatedRowHeight = 0 in viewDidLoad()
2. add the following:
override func viewDidLayoutSubviews() {
// 60 is row's height as set by tableView( cellRowAt )
// places is of type [String] to be used by tableView
tableView.contentSize.height = 60 * CGFloat(places.count)
}

Answer 10

You may as well subclass the UITableView and call whomever you want (i.e. it's container view) from it's layoutSubviews() where you definitely have a proper contentSize.

Answer 11

Block based KVO approach
var contentSizeObserver: NSKeyValueObservation?
#IBOutlet weak var myTableView: UITableView!
#IBOutlet weak var tableHeightConstraint: NSLayoutConstraint!
override func viewDidLoad() {
contentSizeObserver = myTableView.observe(\UITableView.contentSize, options: [NSKeyValueObservingOptions.new], changeHandler: { _, change in
if let contentSize = change.newValue {
self.tableHeightConstraint.constant = contentSize.height
}
})
}
override func viewWillDisappear(_ animated: Bool) {
contentSizeObserver = nil
super.viewWillDisappear(true)
}

Answer 12

Use this function inside your viewWillLayoutSubviews and call the second function after every reload. Then this problem will be solved.
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
dynamicHegihtChange()
}
func dynamicHegihtChange(){
yourTableName.invalidateIntrinsicContentSize()
yourTableName.layoutIfNeeded()
let addtionalPadding = 10
let height = yourTableName.contentSize.height
self.sevicesTableViewHeightConstraint?.constant =
height+addtionalPadding
}
//for reloading the table
func serviceTableReload(){
DispatchQueue.main.async {
self.servicesTableView.reloadData()
self.dynamicHegihtChange()
}
}