The cells with the blue bar are the cell I want to change the height for based on how many green cells there are.
Right now I can make the cell change size but looks really choppy I do this by using,
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 400, height: (50 * actionSteps[indexPath.row].SubActionSteps.count) + 100)
}
Is there any way to animate the change in height?
Try this:
actionSteps[indexPath.row].SubActionSteps.append("") /// or whatever you're currently doing
collectionView.performBatchUpdates(nil, completion: nil)
Related
I have a UICollectionView with a custom cell, however, I am trying to impose constraints on the UICollectionView, so it is always half the width of the screen and half the height of the screen. The one issue I continually encounter is that while the UICollectionView changes according to what device the app is deployed on, the UICollectionViewCells hold the exact same pixel width and height dimensions. This is the code I have tried to implement to make each cell the same height and width as the CollectionView.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let height = collectionView.frame.height
let width = collectionView.frame.width
return CGSize(width: width, height: height)
}
This code, however, doesn't work as the size of the cells are simply the values that are specified in the size inspector for the UICollectionView.
I'm unable to figure out what I am doing wrong here with my code. Thank you very much in advance for your help.
The issue is your collection view cell size is fixed always. So the cell size is not adjust according to screen size.Use view frame size.(remove values from size inspector)
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: view.frame.height)
}
I'm new to iOS and Swift, I'm trying to create a UICollectionView for the first time.
Something is not quite right when running what I made. Here's what it looks like in my storyboard:
But when I run:
Top grey area became longer than before and bottoms of the cells seem clipped. I just wrote few lines of code to make the cells' height equal to the collection view's.
let height = collectionView.frame.height
cell.frame.size.height = height
return cell
Any suggestions?
Swift 4 code is here
1) Uncheck the Automatic field of the Row Height in the attribute inspector.
2) Then set the delegate funcitons
extension ViewController : UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
var width = CGFloat(80) //change "80" with your cell width
return CGSize(width: width ,height : self.collectionView.frame.height)
}
}
Please use collectionViewLayout to give a size for an item,
class YourController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout
and
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let height = collectionView.frame.height
let width = UIScreen.main.bounds.width / 3
let size = CGSize(width: width, height: height)
return size
}
You can make changes from storyboard or from code. I have done from storyboard as shown in image.
And also write this method in your view controller to give a size to your item. For that inherit UICollectionViewDelegateFlowLayout method in your view controller.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let size = collectionView.frame.width / 3
return CGSize(width: size - 20, height: size - 20 )
}
Note: This is just an example. You can set your collection view cell frame.
To change height in a collection view, do not change the cell frame height. There is another delegate for the collection view to set cell height and width.
extension ViewControll : UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
{
return CGSize(width: anyWidth, height: collectionView.frame.size.height)
}
}
Here, anyWidth means whatever width you put. It's up to you
I have a UICollectionView and I have implemented the delegate to calculate the width of my cells for 0 spacing between cells.
It works great on its own, but when I have it inside a container view less than the size of the device, iOS incorrectly works out the spacing between the cells adding a horizontal space I don't want.
I have verified the width I am using to calculate the cell size is correct, so I'm not sure what is causing the problem.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let widthPerItem = view.frame.width / itemsPerRow
return CGSize(width: widthPerItem, height: 60)
}
You are calculating your cell size based upon the size of the view. Since the collectionView doesn't take up the full width of the screen, you are getting the incorrect value. Instead, you should base your calculation on the width of the collectionView itself.
Use the bounds of the collectionView instead of the frame of the view:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let widthPerItem = collectionView.bounds.width / itemsPerRow
return CGSize(width: widthPerItem, height: 60)
}
Ok, the problem was actually related to my uicollectionviewcontroller not correctly sizing to it's parent container view. Changing to a uiviewcontroller with an embedded uicollectionview plus constraints fixed the problem.
I want to display a collection view image which looks like so...
Here, as you can see the whole cell is of a rectangle shape with space for text and buttons below the image. I am not able to load such a 'rectangle' shaped cell in my collectioview. Any help would be appreciated.
Thanks in advance...:)
To set the size of item of a collectionview you can implement this UICollectionViewDelegateFlowLayout method
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 30, height: 100)
}
Your question is not very clear as it does not show your code or what result you got. But it is quiet simple
For customising cell size use below code and pass width and height accordingly
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: accordingly to your requirement, height: accordingly to your requirement)
}
Please check this link which can explain every bit in detail. And play with different value to get your required result.
Custom cell collectionview
I'm using this method below in my UICollectionView to stretch/fill the cell, but it seems like it's constraining to the margins. It's stopping like 10 px shy of the edges. I basically want to set the constraints of the cell to "0" and "0" to fill the width completely and NOT constrained to the margins.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
let customHeight = CGFloat(116)
return CGSize(width: collectionView.frame.size.width, height: customHeight)