How to dynamically increase height of UITableview based on scrolling - ios

Question

I want to increase the height of UITableView when user scroll to top and decrease height when user scroll to down.
I have done this situation by this code
if scrollView == tableView {
print(scrollView.contentOffset.y)
let height: CGFloat = scrollView.contentOffset.y+200
let maxHeight: CGFloat = self.view.bounds.size.height - 64
let minHeight:CGFloat = 200
if height < maxHeight && height > minHeight {
UIView.animateWithDuration(0.25, animations: {() -> Void in
self.tblHeightCons.constant = height
self.view.setNeedsUpdateConstraints()
})
}
}
https://drive.google.com/file/d/0B9WA3RAMmfrKQlBVOG9NaEllRTQ/view
But i don't want to move contents..

Answer 1

Updated. It implements the effect like in videos, and disable the content moving when scrolling in range, and enable the content moving when scrolling out of range. The fast scrolling problem is also fixed:
public func scrollViewDidScroll(_ scrollView: UIScrollView) {
let maxHeight: CGFloat = self.view.bounds.size.height - 64
let minHeight:CGFloat = 200
var height = self.tblHeightCons.constant + scrollView.contentOffset.y
if height > maxHeight {
height = maxHeight
}
else if height < minHeight {
height = minHeight
}
else{
scrollView.contentOffset = CGPoint(x: 0, y: 0)
}
self.tblHeightCons.constant = height
}

Answer 2

The best way i have used following way to achieve this, set your dynamic height to tableview and set contentSize for scrollview in the tableView:numberOfRowsInSection: method.
_commentsTable.frame = CGRectMake(self.commentsTable.frame.origin.x, self.commentsTable.frame.origin.y, self.commentsTable.frame.size.width,cellDynamicHeight*_commentArray.count) ;
self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width, self.scrollView.frame.size.height+kConstantHeight);

Answer 3

This will automatically handle scrollview and tableview in accordance with tableview height.
#IBOutlet weak var heightConstraint: NSLayoutConstraint!// tableView height constraint
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
self.heightConstraint.constant = tableView.contentSize.height
}