I am Trying to resize my cell based on the screen size so that there is only 2 cell per row. I am using the code
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: MyCollectionView.bounds.width / 2.2, height: MyCollectionView.bounds.height / 5.5)
}
This works and resizes to the different screen sizes. I run it on. however when you rotate into landscape mode it displays more than two cells per row.
If The container of MyCollectionView is self.view then plz give a try to this . .
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: self.view.frame.width / 2.2 , height: MyCollectionView.bounds.height / 5.5)
}
Related
The code to set the width and height of the collectionView's cell is as following:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.frame.width/6, height: collectionView.frame.width/5)
}
When the Simulator is vertical before running the scheme, then we get
and
But when the Simulator is horizontal before running the scheme, we get
and
The size of cells will change as the Simulator's initial state. I think the reason is that collectionView.frame.width depends on the Simulator's state.
How to fix the cell's size using auto layout like the code before regardless the ipad's initial state?
Best and easiest way to get through this is to make it a sqaure rather than a Rectangle . basically have the same value to width/height in my opinion . If it doesnt help you try to below and one small change to your code is to use the bounds instead of the frames .
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.bounds.width/5, height: collectionView.bounds.width/5)
}
also if you could guess a size margin in betweens you could also reduce that bounds.width/5 -10
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let standardWidth = max(collectionView.frame.width, collectionView.frame.height)
return CGSize(width: standardWidth/5, height: standardWidth/5)
}
This simple solution works well.
Width/height of my UICollectionView matches all available space.
I want to display two cells in one row (two columns)
So width of one cell should take half width of UICollectionView (collectionView.frame.width / 2)
So I programmatically change width of cell in function of UICollectionViewDelegateFlowLayout:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.frame.width / 2.0, height: 150)
}
But visually width of cell is much bigger than collectionView.frame.width / 2.0 (tested on iPhone SE simulator)
So it takes more than half-width space of screen
Here I printed info about sizes:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath)
print("didSelectItemAt \(cell.frame.width), table width: \(collectionView.frame.width), item calc width: \(collectionView.frame.width / 2)")
}
didSelectItemAt cell width 187.5, table width: 375.0, half-width:
187.5
Why does it happen?
There is also an issue with margins but first I have to solve this one
Update
Though it works fine with iPhone 6s Simulator (I edited image to place two items in the first row to check if they fit):
So what is wrong with iPhone SE?
I don't want to find out that there can be the same issue with other iPhones or iPads too
375.0 is the size of iPhone 6s and X, not iPhone SE which is 320.0
The reason is there is a width constraint of collectionView which was set at iPhone 6s mode but later when switching to the SE simulator, this constraint was not updated.
I think there is problem of cell spacing. it seems there is default cell spacing exists in your implementation. you should try below code to adjust two cell in one raw of collectionview:
extension ViewController : UICollectionViewDelegateFlowLayout{
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let collectionViewWidth = collectionView.bounds.width
return CGSize(width: collectionViewWidth/2, height: 150)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
}
moreover, you should check constraint of your UICollectionView if it is as per your requirement Or not.
Try to use the wide from the view, not the collectionView.
Try this:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: (view.frame.width / 2.0) - 5, height: 150) // provide little bit space between cells
}
Hope this will help.
The best solution is, to reload your collection view in main thread with a bit delay.
DispatchQueue.main.asyncAfter(deadline: .now() + 0.10) {
self.myCollectionView.reloadData()
}
after update to ios 12 and xcode 10 the collectionView with cell sizeing cell does not work correctly anymore.
i have this layout in xcode
the view is like this.
and this is how it looks now.
i have tried to set the collectionview view a widht constraint and modified in the
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
cell.widthConstraint.constant = UIScreen.main.bounds.width / 3
but nothing happens.
You were using the wrong method to set the cells size.
Instead of collectionView(_:cellForItemAt:) use collectionView:layout:sizeForItemAtIndexPath:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let itemHeight = 60
let itemWidth = UIScreen.main.bounds.width / 3
return CGSize(width: itemWidth, height: itemHeight)
}
Also, you can set up items size using Interface Builders Size Inspector, but in that case, the size of your cells will be absolute. If you want it to be 1/3 of screen width, you need to use the layout delegate.
I have a UICollectionView in my app. I want it to constrain so it only has two cells on each horizontal row. For iPhone classes I achieve this by setting the width so three cells can't fit in the same horizontal row. This seems to be a fix but I don't know how to resize the cell for iPads. I have heard to use:
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
but I can't access this function. Does Swift no longer support this function anymore?
Question: Can I force my screen to only display 2 cells on each horizontal row?
You should first conform to protocol UICollectionViewDelegateFlowLayout
and then implement the method :
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.frame.size.width * 0.5, height: 30)
}
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)