CollectionView Layout after rotate - ios

I have a collection view that shows my photo library. After I select a cell, it will segue to another collection view which the cell frame is full-screen size.
The portrait orientation seems fine. However, when I rotate to landscape, something messes up.
When there is no viewWillTransition, the itemSize will not reshape, so it just like the image below.
With viewWillTransition, the collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize will be called, and the itemSize reshaped. However, it is still not expected, any suggestions?
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
super.viewWillTransition(to: size, with: coordinator)
collectionView?.collectionViewLayout.invalidateLayout()
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return self.view.bounds.size
}
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
}

extend class with UICollectionViewDelegateFlowLayout
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: UIScreen.main.bounds.size.width, height: UIScreen.main.bounds.size.height-20)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat{
return 0
}

Related

the unexpected spaces between the rows and the columns in a collection view

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 {
return CGSize(width: (collectionView.frame.size.width/3), height: collectionView.frame.size.height/2)
}
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
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print(indexPath.item)
}
}
The numbers are all zero but there are still spaces between each row and column. And, the space between the rows is bigger than that between the columns. For more information, I put constraints of leading, trailing, top and bottom on the collection view. Does anyone know why this happens?

collectionview cell is not visible even after delegate methods are getting called

I have a UICollectionview of size height 40. UICollectionviewcell of (25,25). Cells are not getting shown. every delegate method call is working fine.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 25.0, height: 25.0)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 1.0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 1.0
}
class yourviewcontroller:UICollectionViewDelegate ,UICollectionViewDataSource ,UICollectionViewDelegateFlowLayout{
}
UICollectionViewDelegateFlowLayout add this

How can I resize the cells in a collection view dependent on the device screen size?

I'm working in Swift and I want my cells to look similar to how it does on this picture on an iPhone 8 plus
But when I load it on a iPad, the size of the cells do not adjust to the screen size. It looks like this:
Does anyone know how I can do this in my CollectionViewController?
Try this.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let yourWidth = (collectionView.bounds.width) / 10.0
let yourHeight = yourWidth
return CGSize(width: yourWidth, height: yourHeight)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsetsMake(0, 0, 0, 0)
}
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
}
There is a delegate Method in UICollectionViewDelegateFlowLayout
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let collectionViewCellSize = collectionView.frame.size.width / 10 // to show 10 cells in a row
return CGSize(width: collectionViewCellSize, height: collectionViewCellSize)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsetsMake(0, 0, 0, 0)
}
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
}

Why strange lines displaying in collection view?

I am currently working in creating a custom calendar where I tried to display Seven cells in a row , But unfortunately some lines occurs randomly can any one guide the error.I have attached the screen shot
I have attached the sample code:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let s = CGSize(width: CGFloat(UIScreen.main.bounds.size.width / 7), height: CGFloat(UIScreen.main.bounds.size.height / 7))
return s
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsetsMake(0,0,0,0)
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return numDays+weekday
}
You can manage it by UICollectionViewDelegateFlowLayout methods
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0 // OR change as you need
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0 // OR change as you need
}
This behaviour appears when you compute the size of your cell.
Hear, you are doing :
func collectionView(_ collectionView: UICollectionView, layout
collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let s = CGSize(width: CGFloat(UIScreen.main.bounds.size.width / 7), height: CGFloat(UIScreen.main.bounds.size.height / 7))
return s
}
The cell's size may not be rounded, therefor the runtime tries to do its best to fill the collection view with your constraints but end up with these little flaws.

UICollection horizontally scroll, so reduce the space between cell item [closed]

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Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 12 months ago.
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I take UICollectionView and set horizontal scroll. Now In this one image view is there, All working perfect except cell spacing. In collectionView I set the Minimum Spacing for cells 0 (Zero). But still Spaces is there.
My output is like that:
But I need this type of output:
And one more thing is that I refer so many answer but still no idea what to do. I use Xcode 7.0 so I need solution in swift 2.0 and if possible then also request to give answer in swift 3.0.
Don't forget to set collectionview flowlayout delegate:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
return CGSize(width: collectionViewTable.bounds.size.width/2 - 20, height: 160)
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
insetForSectionAt section: Int) -> UIEdgeInsets
{
return UIEdgeInsetsMake( 5, 14, 5, 14)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAtIndex section: Int) -> CGFloat {
return 20;
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAtIndex section: Int) -> CGFloat {
return 20;
}
You can set cells and lines spacing from size inspector.
You can also set from UICollectionViewDelegateFlowLayout.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat
Add following methods in your code and manipulate until your desire output.
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: CGFloat(collectionView.frame.size.width/ 2 - 5), height: CGFloat(135)) // 2 is indicates number of cell in row
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
insetForSectionAt section: Int) -> UIEdgeInsets{
return UIEdgeInsetsMake(0, 0, 0, 0)
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 10.0
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 10.0
}
My code is all good. But I don't gate the out put what I want so I try new thing that give - minus value
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAtIndex section: Int) -> CGFloat {
return -20;
}
So only using this one method with minus value and I get my desired output.
Thanks to all who try to solve this bug for me...

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