Auto height cell after add text - swift

Question

I have tableView and when i type i want auto height cell. But i don't know how to fix it. My first idea was:
self.chatTableView.cellForRowAtIndexPath(indexPath)?.textLabel?.text = new_char
self.chatTableView.cellForRowAtIndexPath(indexPath)?.sizeToFit()
self.chatTableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: UITableViewScrollPosition.Bottom, animated: false)
When i have this line with .sizeToFit() my result looks like this:
But when i comment this line:
self.chatTableView.cellForRowAtIndexPath(indexPath)?.textLabel?.text = new_char
self.chatTableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: UITableViewScrollPosition.Bottom, animated: false)
My result looks this:
Is any way to fix it ?

Answer 1

You have changed the height of your UITableViewCell directly. But the height of the cell is handled in the UITableView. To make this work you have to do two things:
1. Use self sizing cells:
Just add this two lines of code to your viewDidLoadmethod:
override func viewDidLoad() {
super.viewDidLoad()
...
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 40
}
The estimatedRowHeight is only used to calculate the scroll bar size and position so you just put the normal expected height of your cells here.
2. Reload the cell after you changed the text
After you changed the text of your cell's label, you have to tell the UITableView to reload this cell so that its height gets adjusted. You do this by calling this method:
func addSomeText() {
// add the text to your data source
tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .Automatic)
}
Obviously the indexPath is your cell's indexPath.
One important thing: You cannot add the new text directly to the cell. Instead you have to add it to your dataSource. Otherwise the text will be gone after the reload, because the cell gets its text from the dataSource when it is dequeued.