smileyborg

// For the best results, your tableHeaderView/tableFooterView should be a UITableViewHeaderFooterView with your content inside the contentView.
let tableHeaderView = UITableViewHeaderFooterView()
    
let fittingSize = CGSize(width: tableView.bounds.width - (tableView.safeAreaInsets.left + tableView.safeAreaInsets.right), height: 0)
let size = tableHeaderView.systemLayoutSizeFitting(fittingSize, withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel)
tableHeaderView.frame = CGRect(origin: .zero, size: size)
tableView.tableHeaderView = tableHeaderView

// When you set this view to the tableHeaderView/tableFooterView on the table view, the table view will preserve the existing size of its frame.
// If you need to change the size, remove the tableHeaderView/tableFooterView, set a new frame on it, then re-set it on the table view again.

TimMedcalf

/*

One of the first things someone new to iOS Development finds is that dealing with the keyboard is trickier
than they think it should be. Simply changing the scrolling extents of a UITableView (or UIScrollView, or 
UICollectionView) that is partially covered by they keyboard reveals a lot about the internals of how iOS
works and highlights various "gotchas" that need to be considered.

There are various ways to know that a keyboard has been shown - but observing some specific notifications
provides a reliable way to allow you to modify your views to deal with it.