There were auto-resizable table view cells introduced in iOS8 (WWDC Session 226 What's new in table and collection views).
In my project I'm trying to implement old fixed rows height behavior. Also, the most important thing for me is to inset default cell.contentView frame with margins on the left and right side.
So, I change the cell.contentView.frame property and immediately after that the -[cell setNeedsLayout] method is being called and and it leads to cell get stuck in an infinite layoutSubviews loop.
Steps to reproduce:
Create new single view project and replace default view controller with the table view controller
Disable table view automatic height calculation
-(void)viewDidLoad {
[super viewDidLoad];
self.tableView.estimatedRowHeight = 0;
self.tableView.rowHeight = 44;
}
3. Drop a custom cell in the table view in storyboard,
Add any subview to the custom cell:,
Subclass the cell and change contentView.frame in layoutSubviews,
Build and run.
Result:
Simulator ends up in a black screen stuck in a infinite layout subviews loop.
Expected Result:
Simulator displaying a table view with a cell's contentView having a custom frame.
Comment:
While debugging a little bit, I found that the infinite loop can be avoided if the cell does not have any custom subviews dropped on it. So it seems the bug will appear after the following conditions are met:
self.tableView.estimatedRowHeight = 0; self.tableView.rowHeight = 44;
cell.contentView.frame = CGRectMake(...)
cell have custom subviews dropped on it in xib or storyboard
Apple does not have the issue in the "Known issues" list for iOS8, so I'm wondering is it actually a bug in iOS8 or does anybody know how to resolve the issue?
This is not a bug: setNeedsLayout will be called any time you change view's frame.
My guess is that changing cell.contentView.frame also changes cell.bounds in iOS 8, triggering relayout. This behavior may be different between iOS versions; anyway, those are standard views, so we shouldn't change them in unsupported ways.
Rather than operating on cell.contentView, how about adding a custom view with insets to it? Or simply creating a height constraint?
In ViewDidLoad please use the below line and there is no need to give the row height
-(void)viewDidLoad {
[super viewDidLoad];
self.tableView.estimatedRowHeight = 44.0f;
self.tableView.rowHeight = UITableViewAutomaticDimension;
}
Related
I need pretty simple thing - table cells which automatically detect their own height. There are a lot of examples out there, which basically say "set couple of flags and values on your table and use autolayout in your cell". My case is a bit special - I load the content of the cell from a separate XIB file which is a plain UIView. The first problem comes already when I create that XIB file in interface builder - I don't know how to make it's height to "calculate" according to constraints that I specify. I am always getting IB errors unless I switch to "Freeform" and resize the view to the height matching my constraints. If I don't do that, I will get the following errors:
In the above example I just need a view which height will be 32 (image height) + 2 * 16 (vertical distance constraints of image from parent's top and bottom) plus the margins. Resizing the freeform view in IB until the errors disappear seems like a dirty hack to me, and it is actually not autolayout. As a next step, I define a cell class, where I put this xib view, something like this (sorry for objc code, almost done porting the project to swift):
- (void)awakeFromNib {
[super awakeFromNib];
[[NSBundle mainBundle] loadNibNamed:#"CellContent" owner:self options:nil];
// self.content is an outlet which gets the root of the XIB on load
[self.contentView addSubview:self.content];
self.contentView.translatesAutoresizingMaskIntoConstraints = NO;
[self.contentView.leftAnchor constraintEqualToAnchor:self.content.leftAnchor].active = YES;
[self.contentView.rightAnchor constraintEqualToAnchor:self.content.rightAnchor].active = YES;
[self.contentView.topAnchor constraintEqualToAnchor:self.content.topAnchor].active = YES;
[self.contentView.bottomAnchor constraintEqualToAnchor:self.content.bottomAnchor].active = YES;
}
As you might guess, when I run this the cell height is the big freeform one, like in the IB of the content XIB, so no auto layout. It seems like the freeform height is even added as another constraint and there is a constraint conflict which results in some of them being broken at runtime.
Let me know how can I fix this, easily create content views for my cells which have auto heights and which I can embed in my cells to benefit the tableView.rowHeight = UITableViewAutomaticDimension magic?
Maybe you forgot to set the Content Hugging Priority and Content Compression Resistence Priority of the Labels.enter image description here
I found what was my problem. Actually, there were conflicts with constraints added because of autoresizing. So I changed this line (from the question above):
self.contentView.translatesAutoresizingMaskIntoConstraints = NO;
to:
self.content.translatesAutoresizingMaskIntoConstraints = NO;
Stupid mistake, the translatesAutoresizingMaskIntoConstraints flag should be disabled for the child view after adding, not for the parent view, as I incorrectly did. After that the magic with cell auto height detection started working like charm.
Make sure UILabel has multiline property . So , Set 0 for Line Property at Attribute Inspector .
Make sure that UILabel Auto-Layout is properly relative to Left-Right-Top-Bottom .
Apply these delegate Functions :
-(CGFloat) tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return UITableViewAutomaticDimension;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return UITableViewAutomaticDimension;
}
I have a UIView in which I am adding a UICollectionView to act as a banner view to look like a carousel. The Viewcontroller in which UIView is present, is part of pageviewcontroller.
PageVC --> UIViewController --> UIView --> UICollectionView.
Each VC has its own banner, so when the page is swiped, I reload the collectionView with the respective data and I am able to see it. Now if visit a page which I already visited, the collectionview cell disappears. The collectionview is visible but the cell is somehow hidden.
The collectionview cell is a customcell and I am not using any custom layout, I am using the default flowlayout. This is working fine in iOS8-devices.
Below is the debugger output,
When cell is visible:
CollectionViewCell: 0x7f9db8d9ffa0; baseClass = UICollectionViewCell; frame = (209 3.5; 209 96); clipsToBounds = YES; opaque = NO; layer = <CALayer: 0x7f9dbb5dde60>>
When invisible (you can see its hidden now) the dequed cell is now hidden, no clue why it is happening
CollectionViewCell: 0x7f9dbb5897e0; baseClass = UICollectionViewCell; frame = (0 3.5; 209 96); clipsToBounds = YES; hidden = YES; opaque = NO; layer = <CALayer: 0x7f9dbb590220>>
indexPathsForVisibleItems is returning nil.
I was calling reloadData from multiple places which caused the system to get confused (may be) especially I have written reloadData in my updateconstraints method and hence for each minor constraint change reloadData was getting called.
Check all places from where you call reloadData for collectionview if you're experiencing the same problem.
I've encountered the same problem.
After
checking if the UICollectionView reloadData was called in some thread other than the MainThread
checking if there is any cases about multi-calling reloadData or updateconstraints
without solving my problem, I realized that in some occasions CGSizeZero was returned for collectionView:layout:sizeForItemAtIndexPath:.
When avoiding the CGSizeZero result, everything works well.
Same problem.
Here's my situation:
My collection view has a custom layout. I use the default flow layout without any problem.
When I use my custom layout, whose cell width is a half screen width. When I scroll to the 5th cell, all cells became hidden without reason.
Finally I found out that when I set cell's size correctly in the layout class of the storyboard, the problem is resolved.
Hope this helps.
I have setup a tableview to use self-sizing cells (in fact I didn't have to do anything more than use auto layout - it seems that UITableViewAutomaticDimension is the default rowHeight).
The cells are sized correctly:
However, when I push another controller on to the stack, the cells immediately resize just before the transition animation:
They remain at the incorrect size when I pop back to the table view controller. I can partially resolve this part by reloading on viewWillAppear to recalculate the correct heights, but then I lose some other animations and selection state.
Is this an iOS bug? How might I work around it?
Here is a sample project that demonstrates the same.
You need to set estimatedRowHeight:
- (void)viewDidLoad
{
[super viewDidLoad];
[self.tableView registerClass:[Cell class] forCellReuseIdentifier:#"Cell"];
self.tableView.rowHeight = UITableViewAutomaticDimension;
self.tableView.estimatedRowHeight = 80;
}
I'm creating my UI entirely in code and using Masonry to constrain the cell's content view's subviews to the appropriate height. I'm using
[cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height
on iOS 7 for the row height, while iOS 8 handles it automatically.
Everything looks exactly as it should on screen, but in the console I get trainloads of warnings for conflicting constraints, which all seem to be caused by an unasked and unnecessary height constraint on the cell's content view (e.g. <NSLayoutConstraint UITableViewCellContentView.height == 44>).
On iOS 8 I'm setting the table view's rowHeight as UITableViewAutomaticDimension (effectively -1) but still I get this constraint. I'm only adding constraints between the content view and its own subviews, so no constraints between the content view and the cell itself.
Any idea where this constraint comes from and how to make it go away?
Edit: Now I actually found a "solution" of sorts – initially setting the content view's frame to something ridiculous, like CGRectMake(0, 0, 99999, 99999), before adding subviews or constraints, seems to make the warnings go away. But this doesn't exactly smell like the right way to do it, so can anyone tell of a better approach?
I had the same issue and fixed it setting the auto resizing mask of the cell like this:
override func awakeFromNib() {
super.awakeFromNib()
self.contentView.autoresizingMask = .flexibleHeight
}
Also in the controller I set the estimated height and tell the table view to use automatic dimension (in the viewDidLoad method:
self.tableView.estimatedRowHeight = 120
self.tableView.rowHeight = UITableView.automaticDimension
These links helped:
http://useyourloaf.com/blog/2014/08/07/self-sizing-table-view-cells.html
Auto layout constraints issue on iOS7 in UITableViewCell
Hope this helps!
To tack on to the accept answer- after months of trying to get iOS 8's automatic cell sizing to work I discovered an important caveat. The 'estimatedRowHeight' property MUST be set. Either via the tableView directly or by implementing the delegate methods. Even if there's no way to determine a valid estimate, simply providing a value other than the default (0.0) has demonstrably allowed iOS 8's cell layout to work in my testing.
Regarding to the "solution" mentioned in the edit in the question (setting the contentView frame to something big temporarily), here's proof this is a good "solution":
https://github.com/smileyborg/TableViewCellWithAutoLayoutiOS8/blob/master/TableViewCellWithAutoLayout/TableViewController/TableViewCell.swift
// Note: if the constraints you add below require a larger cell size than the current size (which is likely to be the default size {320, 44}), you'll get an exception.
// As a fix, you can temporarily increase the size of the cell's contentView so that this does not occur using code similar to the line below.
// See here for further discussion: https://github.com/Alex311/TableCellWithAutoLayout/commit/bde387b27e33605eeac3465475d2f2ff9775f163#commitcomment-4633188
// contentView.bounds = CGRect(x: 0.0, y: 0.0, width: 99999.0, height: 99999.0)
It's hacky but it seems to work.
- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
if (self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
//self.contentView.translatesAutoresizingMaskIntoConstraints = NO;
self.contentView.autoresizingMask = UIViewAutoresizingFlexibleHeight;
self.itemView = [CustomItemView new];
[self.contentView addSubview:self.itemView];
}
return self;
}
set translatesAutoresizingMaskIntoConstraints to NO is not work for me
, but autoresizingMask = UIViewAutoresizingFlexibleHeight is well.
you should also making constraints like this:
- (void)updateConstraints {
[self.itemView mas_updateConstraints:^(MASConstraintMaker *make) {
make.leading.trailing.top.equalTo(0);
//make.bottom.equalTo(0);
make.bottom.lessThanOrEqualTo(0);
}];
[super updateConstraints];
}
bottom constraints not just equalTo contentView's bottom, you should use lessThanOrEqualTo
hope this is work to you!
I found out that in some cases, setting an estimatedHeight that is many times bigger the height of my average cell fixed most if not all warnings and had no negative impact on the display.
i.e.:
Setting self.tableView.estimatedRowHeight = 500.0f while most rows are only about 100.0f in height fixed my issue.
My UICollectionView cells don't get displayed on iOS6, because my delegate method cellForItemAtIndexPath doesn't get called. I suspect because of this warning:
the behavior of the UICollectionViewFlowLayout is not defined because:
the item height must be less that the height of the `UICollectionView`
minus the section inset's top and bottom values.
I don't get the warning on iOS7, and all the cells display correctly there too.
I've set my collectionView frame to height 270 in the .xib and there are no insets defined.
I've set my cell height to 270 in the .xib.
I can print out my collectionView frame at runtime and it's 271.
Also, my collectionview is actually inside a custom tableview cell.
Any ideas?
Thanks!
Try to set self.automaticallyAdjustsScrollViewInsets = NO
This was introduced in ios7 so you might want to wrap that with an ios version check, if you are supporting ios6 and below.
This fixed my problem! In my .xib, setting my Collection View Size Cell Size to a smaller value.
My setup is that I have this collectionview inside a custom tableview cell and
I do return the height of my tableview cell programatically (depending on the content). So it could be that my warnings had to do with my collectionview not fitting inside the tableview cell. So setting the initial collectionview to a smaller value fixed it.
I was on the wrong path thinking that the problem was with my collectionview and its colletionview cell.
Maybe?
self.automaticallyAdjustsScrollViewInsets = NO
actually did the trick. it also resolved my issue in swift, where the cells of a horizontal flow layout had a frame top of -32 (???) and did not fit into the collection view properly.
I found that I had to manually set self.collectionView.collectionViewLayout.itemSize in viewWillLayoutSubviews.
- (void)viewWillLayoutSubviews {
self.collectionView.collectionViewLayout.itemSize = CGRectMake(...);
}
Another possibility to generate the same trick would be to implement the method
collectionView:layout:sizeForItemAtIndexPath:
I have the same issue, in my case the size of collectionCell in storyboard is 96x96 and also under -(CGSize)collectionView:layout:sizeForItemAtIndexPath:
the solution was removing this delegate:
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
UIEdgeInsets insets = {.left = 10, .right = 10, .top = 5, .bottom = 5};
return insets;
}
And by the way this is under ios7, it's late but hope this will help some.. Cheers..
Set:
self.itemSize = CGSizeMake(1, 1);