问题
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?
回答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)
}
}
回答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
}
回答3:
1) Override collectionflowlayout delegate method
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
return CGSizeMake(50, 50); //(width,hight)
}
2) In above method, Calculate the height of textview which contains dynamic length and add that value in your fixed height. Ex. cellHeight = 100 + textview height. //100 is height which not contain textview height.
3) After calculating height, replace it in above method
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
return CGSizeMake(50, dynamicheight); //(width,hight)
}
来源：https://stackoverflow.com/questions/38759138/how-to-make-uicollectionview-cell-height-dynamic