I implemented UICollection view cell with Auto Layout. It works fine.
But my cell height is dynamic so cell should be change its height as per constraint set.
but height is not changed in any case.
My Code
- (void)viewDidLoad {
[super viewDidLoad];
UICollectionViewFlowLayout *flowlayout = (UICollectionViewFlowLayout*)_col.collectionViewLayout;
flowlayout.estimatedItemSize = CGSizeMake(self.view.frame.size.width - 30, 600);
}
-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
FirstCell *cell = [_col dequeueReusableCellWithReuseIdentifier:#"FirstCell" forIndexPath:indexPath];
return cell;
}
Storyboard
Simulator
All labels are multi lined
Help me to solve this
thanks for your time
Please follow below thing to achieve self sizing collection cell.
1) Same as table cells, use constraints or override -sizeThatFits:.
2) Override -[UICollectionReusableView preferredLayoutAttributesFittingAttributes:] to adjust layout attributes determined by the UICollectionViewLayout.
3) New estimatedItemSize property on UICollectionViewFlowLayout, equivalent to estimatedRowHeight on UITableView.
There are no self-sizing collection view cells in iOS before iOS 10. (Apple has claimed in WWDC videos that this feature exists, but it doesn't.)
You have to implement the delegate method collectionView:layout:sizeForItemAtIndexPath to provide a size for each cell. It can call systemLayoutSizeFittingSize: to use the internal constraints to do that, if you like; but the runtime will not magically do it for you.
I have the following layout in my dynamically-sized Storyboard:
However, when running the application (depending on the orientation), cells look like the following:
This is to be expected, because the previous cells had static heights and widths.
However, I'd like the cells to resize dynamically based on the device width (height can remain static for this purpose). The CollectionView itself resizes properly, because it's pinned to its superview, so how can cells be overridden with auto-layout constraints (vs. the static cell sizes dictated from the UICollectionView).
The simplest way seems to be over-riding the cell size via the delegate within my main View Controller:
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
float cellWidth = (self.view.frame.size.width / 2) - 35;
float cellHeight = cellWidth * 190.0f / 270.0f;
return CGSizeMake(cellWidth, cellHeight);
}
I'd prefer to have as much display logic in the storyboard, but I suppose this is room for future improvement for Apple.
The cell sizes aren't determined by auto layout, they're set by the itemSize property of the layout object. If you only have one cell type, then you only need one cell in the collection view in IB. When your collection view is loaded, you can set that size in code, based on the width of the collection view. I've done it like this,
-(void)viewWillLayoutSubviews {
self.layout.itemSize = CGSizeMake(self.collectionView.bounds.size.width/2.5, 100);
}
I've built a vanilla UICollectionView that uses cells that are the full size of my screen...
The ViewCells I am using are defined in IB with dimensions of 320x568, and I have added auto layout constraints that should allow these to scale down when the window size changes.
Is there a way to have a normal collection view flow layout detect changes in the available window (in-call bar, 3.5 inch screen, etc.), and update the viewcell default sizes so that they match the available real estate, or is this going to require customized code to listen for the change in resolution? If so, what is the method I need to implement to capture this change in window size?
This might work :
Subclass a UICollectionViewFlowLayout and override the method (shouldInvalidateLayoutForBoundsChange) like this :
- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
[self invalidateLayout];
return YES;
}
This will force a refresh of the layout on bounds changes of the collectionView. (a rotation for example).
also you'll have to implement the following method of UICollectionViewDelegate :
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return self.collectionView.bounds.size;
}
Now if you have good constraints on you collectionsView, it's frame should be updated on window changes and result in a layout update.
Let me know if it works :)
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);
I am using UICollectionView using the flow layout.
I have made a custom UICollectionViewCell for the same.
But on running the project the console keeps on throwing this error-
The behavior of the UICollectionViewFlowLayout is not defined because:
the item height must be less that the height of the UICollectionView minus the section insets top and bottom values.
I have made sure that the size of the cell is correct
Has anyone been able to resolve this issue.
I found that, using storyboards, you have to go into the storyboard and click on the overall View Controller (the view should be highlighted in blue) and go to the Attributes Inspector (the fourth tab on the right side of the screen) and unchecking the "Under Top Bars", "Under Bottom Bars", and "Under Opaque Bars." This cleared up the issue for me, and it cleared it for my coworkers as well.
I've been having some issues when the using a collection view to present full screen view controllers.
Basically at run time, it'll ask for the size of the item and simply return the size of the collection view:
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
return self.collectionView.frame.size;
}
I know this is a very late reply, but I have also experienced this.
Inside my view controller, let's call it MyViewController I have a UICollectionView that is using custom UICollectionViewCells. I'm implementing the method collectionView:layout:sizeForItemAtIndexPath where I am returning a item size that is dependent on the height of the UICollectionView.
MyViewController is made in a storyboard using autolayout to control the height of the UIViewController.
The cells look fine when in portrait mode, but did not when in landscape mode.
I solved my issues by invalidating the UICollectionViewLayout of my UICollectionView inside the viewWillLayoutSubviews method.
- (void)viewWillLayoutSubviews {
[self.myCollectionView.collectionViewLayout invalidateLayout];
}
Earlier I had tried to invalidate the layout inside willAnimateRotationToInterfaceOrientation:duration, but it didn't work. The reason for this is probably that the sizes for all the views are not calculated yet, so we have to wait until autolayout has finished its magic. I refer to this SO thread.
Update for Swift 4.0:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
self.myCollectionView.collectionViewLayout.invalidateLayout()
}
Had this issue myself a few times when trying to create collection views with fullscreen cells. My problem was caused by laying out for 4" screen in IB/Storyboard and specifying 320*568 for item size, but running in the simulator using 3.5" screen, which has a height of 480. The solution is to specify your item size in code with something like:
UICollectionViewFlowLayout *layout = (id) self.collectionView.collectionViewLayout;
layout.itemSize = self.collectionView.frame.size;
This ensures that the cell size is set correctly at runtime.
If you are using storyboards and auto layout, debugging this kind of problems is really hard...
I had similar problem when trying to display UICollectionViewCell fullscreen on iPhone.
Most of the time issue is with the size of the cell set in
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)
or directly on flowLayout.itemSize.
But... try:
Select the ViewController:
Then uncheck Extend Edges options:
And now try setting your auto layout constraints.
Good luck.
That fixed my problem:
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return CGSizeMake(self.collectionView.frame.size.width, self.collectionView.frame.size.height - 70);
}
U can see padding value from top and bottom on this screen:
Be sure to set the right autoresizing mask for UICollectionView and UICollectionviewcell.
This fixed my problem for iPhone 4 Simulator
For me I am using AKPickerView inside of a custom UIView which was giving me a slew of warnings like the ones mentioned here. All I did to eliminate the warnings was to Un-Check the box called 'AutoResize Subviews' in the Attributes Inspector for my custom UIView. That silenced the warnings so hard, I thought my logger stopped working.
What caused this for me was that I was trying to set my cells to the size of the superview rather than the size of the UICollectionView. Simply replaced the superview frame with the UICollectionView frame.
I had this problem when I was need full screen cells in collectionView. So I resolved it with this decision.
Cell size is equal collection view size
2. Change in storyboard "Inset from:" from Safe Area to Content Inset
Change "Content Insets" to Never
I just ran into the same error message, but for me the issue was that when I received new data from the api and tried to refresh my collectionView, the method that called [collectionView reloadData] wasn't calling it on the main thread.
Hope this helps someone...
I have same issue
the behavior of the UICollectionViewFlowLayout is not defined because:
the item height must be less than the height of the UICollectionView minus the section insets top and bottom values.
I solved this issue by checking the values in section Insets.And for fix cell size I have used below code.
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
CGSize result = [[UIScreen mainScreen] bounds].size;
CGFloat scale = [UIScreen mainScreen].scale;
result = CGSizeMake(result.width * scale, result.height * scale);
CGFloat cellWidth = [[UIScreen mainScreen] bounds].size.width - 20;
CGFloat cellHeight = [[UIScreen mainScreen] bounds].size.height - 120;
return CGSizeMake(cellWidth, cellHeight);
}
If you're loading a collectionView via a container view + UICollectionViewController, you may have set a height constraint on the container view which is constraining the height of the collection view itself. In my case, I found the collectionView.contentSize was taller than the constraint I had set on my container view.
Obviously this is a bit of an edge case but just in case you have a similar setup, I figured I'd add this comment.
For me the solution was to set Estimate Size (in the storyboard size attributes pane) for the collection view to None.
It's complaining that the item height is bigger than the height of the collectionView. So it's sticking out.
So you have to make the height the same or less.
Like this:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.frame.height, height: collectionView.frame.height)
}
Using the height for the width makes it a square. This is assuming inset is 0 which it should be if you haven't done anything.
None of the above fixes did it for me.
I fixed it with this
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{CGFloat currentWidth = collectionView.frame.size.width;
UIEdgeInsets sectionInset = [(UICollectionViewFlowLayout *)collectionView.collectionViewLayout sectionInset]; //here the sectionInsets are always = 0 because of a timing issue so you need to force set width of an item a few pixels less than the width of the collectionView.
CGFloat width = currentWidth - 10;
}