How to make UICollectionview cell height dynamic?

Question

I have a UIcollectionview. There are some cells of the Collectionview. Inside that CollectionviewCell there is a textview. The textview's content is dynamic. So the cell height should be dynamic.

How to do that?

Solution 1

1-Add UICollectionViewDelegateFlowLayout protocol.
2-Conform to protocol by implement the sizeForItemAtIndexPath method in your ViewController.
3-Use the index of the cell to get the text you have and calculate the height and width of it.

class ViewController: UIViewController,UICollectionViewDelegateFlowLayout{

  func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
     let constraintRect = CGSize(width: self.view.frame.size.width, height: CGFloat.max)
     let data = myTextArray[indexpath.row];
     let boundingBox = data.boundingRectWithSize(constraintRect, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: [NSFontAttributeName: UIFont(name: Constants.strings.fontName, size: 30)!], context: nil)
     return CGSizeMake(boundingBox.width, boundingBox.height); //(width,hight)
  }

}

Solution 2

Use NSAttributedString in sizeForItemAtIndexPath to calculate rect for the height and width:

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {

    let attString = NSAttributedString(string: self.rows[indexPath.row], attributes: [NSFontAttributeName: UIFont.systemFontOfSize(15.0)])
    var r: CGRect = attString.boundingRectWithSize(CGSizeMake(self.collectionView.bounds.size.width, CGFLOAT_MAX), options: .UsesLineFragmentOrigin, context: nil)

    return r.size

}

Comments

[Sajib Ghosh]

Thanks! But the last cell is behaving differently. All the cells are drawn as expected but the leading of the last cell is more than the others cell. Any suggestion?

[Sajib Ghosh]

Thanks! But the last cell is behaving differently. All the cells are drawn as expected but the leading of the last cell is more than the others cell. Any suggestion?

[Ali Baqbani]

If textView use different font and size you must add 'NSFontAttributeName' to 'NSAttributedString' to calculate correct size