Oblique table view cells in iOS - ios

Question

How can I implement this? A table view with oblique cells. I was thinking first to make the cells overlap and cut out a piece, but I can't make it work.
Now the single solution I can think of is to download the second image in first cell and cut out the top triangle and add to the first cell. But that wouldn't be too optimal memory wise and processing wise if the user is scrolling through the list.
I appreciate any advice, thank you!

Answer 1

I've done something similar like this but I didn't use UITableView or UICollectionView.
What I use is having one UIImageView(AView) on top of the other UIImageView(BView) in view hieararchy. So I add UISwipeGestureRecognizer to BView .And at the top of BView I've added a seperator view(when VC load user could not see it). And I basically animating BView however I want.
But since they are not cells in UITableView you can't give "pulling" behavior to user which is a UX disadvantage for your app.

Answer 2

I solved it the following way. I used UICollectionView in the end because I couldn't find a way to overlap nicely the cells from UITableView. So first I made a custom layout which looks like this:
CustomCollectionViewFlowLayout.swift
import UIKit
class CustomCollectionViewFlowLayout: UICollectionViewFlowLayout {
override func collectionViewContentSize() -> CGSize {
let xSize = self.itemSize.width
let ySize = CGFloat(self.collectionView!.numberOfItemsInSection(0)) * self.itemSize.height
var size = CGSizeMake(xSize, ySize)
if self.collectionView!.bounds.size.width > size.width {
size.width = self.collectionView!.bounds.size.width
}
if self.collectionView!.bounds.size.height > size.height {
size.height = self.collectionView!.bounds.size.height
}
return size
}
override func layoutAttributesForElementsInRect(rect: CGRect) -> [AnyObject]? {
let attributesArray = super.layoutAttributesForElementsInRect(rect) as! [UICollectionViewLayoutAttributes]
let numberOfItems = self.collectionView?.numberOfItemsInSection(0)
for attribute in attributesArray {
let xPosition = attribute.center.x
var yPosition = attribute.center.y
if attribute.indexPath.row == 0 {
attribute.zIndex = Int(INT_MAX)
} else {
yPosition -= CGFloat(60 * attribute.indexPath.row)
attribute.zIndex = numberOfItems! - attribute.indexPath.row
}
attribute.center = CGPointMake(xPosition, yPosition)
}
return attributesArray
}
override func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {
return UICollectionViewLayoutAttributes(forCellWithIndexPath: indexPath)
}
}
Then I used paths and shapes to cut out that part and also draw a white rectangle. So it looks like this:
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("ChallengeCollectionViewCell", forIndexPath: indexPath) as! ChallengeCollectionViewCell
cell.challengeImage.sd_setImageWithURL(NSURL(string: STATIC_IMAGE_URL), completed: nil)
let trianglePath = CGPathCreateMutable()
CGPathMoveToPoint(trianglePath, nil, 0, 0)
CGPathAddLineToPoint(trianglePath, nil, 0, cell.challengeImage!.frame.size.height)
CGPathAddLineToPoint(trianglePath, nil, cell.challengeImage!.frame.size.width, cell.challengeImage!.frame.size.height - 50)
CGPathAddLineToPoint(trianglePath, nil, cell.challengeImage!.frame.width, 0)
CGPathAddLineToPoint(trianglePath, nil, 0, 0)
CGPathCloseSubpath(trianglePath)
let shapeLayer = CAShapeLayer()
shapeLayer.frame = cell.challengeImage!.frame
shapeLayer.path = trianglePath
cell.challengeImage.layer.mask = shapeLayer
cell.challengeImage.layer.masksToBounds = true
let linePath = CGPathCreateMutable()
CGPathMoveToPoint(linePath, nil, 0, cell.challengeImage!.frame.size.height)
CGPathAddLineToPoint(linePath, nil, cell.challengeImage!.frame.size.width, cell.challengeImage!.frame.size.height - 50)
CGPathCloseSubpath(linePath)
let lineShape = CAShapeLayer()
lineShape.path = linePath
lineShape.lineWidth = 10
lineShape.strokeColor = UIColor.whiteColor().CGColor
cell.challengeImage.layer.addSublayer(lineShape)
return cell
}
I hope it will be useful for someone who runs into the same problem. Thanks and best wishes!