UITableView Cell display issue - swift

Question

I have a UITableView, its top and bottom distance to superview is 0.
When keyboard appears I update the bottom constraint, so that keyboard will not hide the table. But on updating the bottom constraint, last two or three cells are not completely visible. I am using following code to update the bottom constraint.
func keyboardWillChangeFrameWithNotification(notification: NSNotification, showsKeyboard: Bool) {
let userInfo = notification.userInfo!
let animationDuration: NSTimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber).doubleValue
// Convert the keyboard frame from screen to view coordinates.
let keyboardScreenBeginFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()
if showsKeyboard
{
cntInputViewBottom.constant = keyboardScreenBeginFrame.size.height
}
else
{
cntInputViewBottom.constant = 0
}
}

Answer 1

You are using UIKeyboardFrameBeginUserInfoKey. This is size of the keyboard at the beginning of frame change animation. You should better use UIKeyboardFrameEndUserInfoKey in order to get final frame.

Answer 2

if x is the height of the view with send button.
if showsKeyboard
{
cntInputViewBottom.constant = keyboardScreenBeginFrame.size.height+ x
}
else
{
cntInputViewBottom.constant = x
}

Answer 3

Problem is you are not informing your view/controller to update your constraint before and after.
if showsKeyboard
{
self.view.layoutIfNeeded()
cntInputViewBottom.constant = keyboardScreenBeginFrame.size.height
self.view.layoutIfNeeded()
}
else
{
self.view.layoutIfNeeded()
cntInputViewBottom.constant = 0
self.view.layoutIfNeeded()
}
just add self.view.layoutIfNeeded() before & after updating constraint as displayed.