I am adjusting UILabels and an UIImageView's frame in code in UICollectionViewCell to fit smaller device sizes but I can't seem to scroll to the end of the UICollectionView. There are about two unreachable cells.
I suspect that it could be a constraints problem and I have tried calling updateConstraints or updateConstraints if needed but nothing visible seems to be happening. I make use of AutoLayout in the storyboard.
I think I know what the problem, because you are changing the Cells at runtime, after the contentSize already as been calculated you need to set it manually.
Try to set the collectionViewContentSize manually and tell me if it worked..
Related
I am trying to use the so called "self sizing cell" which means:
set estimatedItemSize on flowLayout
overide preferredLayoutAttributesFittingAttributes in cell class
Such as this: UICollectionView Self Sizing Cells with Auto Layout
And I need dynamic effect like this:http://www.teehanlax.com/blog/implementing-a-bouncy-uicollectionviewlayout-with-uikit-dynamics/
It works fine without UIDynamic, but I need UIDynamic. As what I see, it will call the prepareLayout and layoutAttributesForElementsInRect until die, there will be too many _updateVisibleCellsNow waiting in line.
I have no idea how to solve that, please help me in case u see. Or, if I am using those technologies in wrong way, please let me know.
Two things worked for me:
Make sure your collection view itself has layout constraints defined for placement within its superview.
I got this crash when the estimated size was larger than the final size. If I set the estimated size to a smaller value the crash stopped.
If any size or frame position changed, it will trigger all cells' preferredLayoutAttributesFittingAttributes until all cells' frames did not change.
The behavior flow is as the following:
1. Before self-sizing cell
2. Validated self-sizing cell again after other cells recalculated.
3. Did changed self-sizing cell
If second steps can't get stable all cells' position and size, it will become infinite loop.
Please reference my post here: UICollectionView Self Sizing Cells with Auto Layout
I'm experimenting with autolayout and am running into trouble with UITableViewCell since they're created at runtime. My cells are loaded from a xib from the main ViewController. This xib has View mode set to Aspect Fill.
I've read about different ways to do this online and have yet to get any of them working. What's considered the best way to handle this?
It looks like your constraints aren't set properly, as the cell is shorter than the image's height.
Using AutoLayout and self-sizing cells is the easiest way to handle what you want to do. Once your constraints are setup properly for your custom cell, tableView:cellForRowAtIndexPath: can call dequeueReusableCellWithIdentifier:forIndexPath: and all the subview layout will be handled for you.
See the detailed walkthrough by smileyborg in his answer to Using Auto Layout in UITableView for dynamic cell layouts & variable row heights.
He also provides workarounds for the minor issue with the initial cell width being based on the storyboard cell, instead of the tableView width. I worked around it by setting the cell's initial width to the tableView's width, as Rasputin had suggested.
I am using UICollectionView with horizontal paging enabled. My collectionView frame is less than the screen size.
I used the following code :
myCollectionView.clipsToBounds=FALSE;
Still I am not able to see the views outside the bounds of my collectionView.
I am using custom UICollectionViewLayout
If the size of each page is greater or equal to your collectionView's frame size, you will not be able to see the content outside the frame even clipToBounds is disabled.
In order to save the memory, the cells in the collectionView are reusable and will be removed if they are out of the frame (i.e. only shows the visible cells).
To recreate the effects like the one seen on the App Store:
Try to set the frame of the collectionView as large as your collectionView's superView, and specify proper minimumLineSpacing for your UICollectionViewFlowLayout.
You may like to take a look at this post about targetContentOffsetForProposedContentOffset:withScrollingVelocity which gives you controls to decide the contentOffset of a given page.
I'm not sure but may be the problem when you init your collectionView it's initializing with the some default settings like clipToBounds. Try this method to layout subviews:
-(void)layoutSubviews{
[super layoutSubviews];
myCollectionView.clipsToBounds = FALSE;
}
Hope it works.
I have been struggling with this for a few days now, and I am looking to see if someone can help me with this AutoLayout problem.
In my iOS7 application, I have a UIView that has a UIScrollView and inside it a UIView(container) with some elements positioned. I have in there, a UIImageView, UITableView, UICollectionView, UITextView and a MapView. There is no height constraint on the UIScrollView and the container UIView. There are no height constraints on the UICollectionView and the UITextView.
What I want to accomplish is
The UITextview should expand to the content size as in all the text should appear without any vertical scrolling enabled for the UITextView.
The UICollectionView should always show all items and there should not be any scrolling enabled there as well.
Overall, I want a UIScrollView with items in it, that scale based on content. I have tried numerous things, but failed.
If anyone has pointers or suggestions on how to go about doing this, it would be very helpful.
OK, I would go about this in a completely different way.
First, get rid of the scrollView completely.
Just use a UICollectionView for this entire interface.
The UICollectionView can take a UIView for a section header. Make this UIView with your UITextView inside. You will need to manually calculate the correct height for your UITextView (and UIView).
Something like...
CGSize size = [theText sizeWithFont:<the font used> constrainedToSize:CGSizeMake(desiredWidth, CGFLOAT_MAX)];
Then just populate your collection view.
By doing this your collection view will control all the scrolling. Because you have set the textview to the correct size in the header you will have all the text there.
This is how I would go about it:
I assume your issue is with the height of the views, that affect the scrolling.
In the textViewDidChange: I would set the frame of the UITextView same as it's contentSize. When they are both the same, scrolling gets disabled.
After populating your UITableView and calling reloadData, I would set it's frame same as it's contentSize.
The mapView (MKMapView, I suppose) has the same frame throughout, I suppose. So you just use it's fixed height. If it changes height, you must store it's changing height each time it changes.
Once you have all the heights, add them up, and set the frame of the outer view same as then combined height of the inner view. Iterate this to all nested views, beginning from innermost views, and moving to outer views.
The catch here is, every time your content changes, the frames have to be resized. Hence changing the frames in textViewDidChange:, after reloadData, etc makes sense.
EDIT : One thing you might want to do first is, getting rid of redundant views. Your view hierarchy seems Rube Goldberg to me. The lesser views you have, the lesser work you will have to do.
Ok.. so I solved this problem by creating a IBOutlet for my NSLayoutConstraint on the UITextView in question.
I simply computed the height and then applied it on the constraint and it worked..
#Fogmeister - Your solution will also work, but it would require me to rewire a whole UI page.. Your approach is definitely a feasible one and shall keep in mind for future iOS apps..
When I want to have a custom cell, I generally add a UIView subclass to the cell's content view. For the layout of my subviews I use a nib. Then I wire up the nib to my UIView subclass. My issue is how to dynamically size content. Say my view has a lot UILabels inside it. I use layoutSubviews to position all the subviews - but it is only until that is done that I truly know the height of my cell. So currently in tableView:heightForRowAtIndexPath I setup my subview and call layoutIfNeeded so everything is positioned properly. Now I know the height of my cell and return it in the tableView:heightForRowAtIndexPath method. But now when tableView:cellForRowAtIndexPath is called the cell that I am given has a height of 44.0. When I added my subview to it - my subview is outside of its parent's bounds. Then when the cell is later resized in iOS to the height that I said I needed, my content is thrown off because of my autoresizingMask. Just trying to figure out if this is an issue others deal with or if I'm approaching it completely wrong. It just seems backwards that we ask for the height, then create a cell that is not that height.
Unfortunately, this is how UITableViews work: You need to provide the heights before the UITableViewCells are actually rendered.
And yes, everyone has to deal with it. :)
You could create an NSArray, add all your custom contentViews, set their frame according to the expected contentView bounds and then use this array as data source in tableView:heightForRowAtIndexPath: and tableView:cellForRowAtIndexPath:. While this isn't exactly efficient, it works fine for small data sets.
Also, here's a nice tutorial with this topic:
UITableViewCell Dynamic Height (by Matt Long)
A similar question on SO:
How can I do variable height table cells on the iPhone properly?