Resize UITableViewCell containing UITextView upon typing

Question

I have an UITableViewController that contains a custom cell. Each cell was created using a nib and contains a single non-scrollable UITextView. I have added constraints inside each cell so that the cell adapts its height to the content of the UITextView. So initially my controller looks like this :

Now I want that when the user types something in a cell its content automatically adapts. This question has been asked many times, see in particular this or the second answer here. I have thus written the following delegate in my code :

- (BOOL) textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text {
    [self.tableView beginUpdates];
    [self.tableView endUpdates];
    return YES;
}

However it leads to the following strange behavior : all constraints are ignored and all cells height collapse to the minimal value. See the picture below:

If I scroll down and up the tableView in order to force for a new call of cellForRowAtIndexPath, I recover the correct heights for the cells:

Note that I did not implement heightForRowAtIndexPath as I expect autoLayout to take care of this.

Could someone tell me what I did wrong or help me out here ? Thank you very much !

Answer 1

Here is a swift solution that is working fine for me. Provided you are using auto layout, you need assign a value to estimatedRowHeight and then return UITableViewAutomaticDimension for the row height. Finally do something similar to below in the text view delegate.

override func viewDidLoad() {
    super.viewDidLoad()
    self.tableView.estimatedRowHeight = 44.0
}

override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

// MARK: UITextViewDelegate
func textViewDidChange(textView: UITextView) {

    // Calculate if the text view will change height, then only force 
    // the table to update if it does.  Also disable animations to
    // prevent "jankiness".

    let startHeight = textView.frame.size.height
    let calcHeight = textView.sizeThatFits(textView.frame.size).height  //iOS 8+ only

    if startHeight != calcHeight {

        UIView.setAnimationsEnabled(false) // Disable animations
        self.tableView.beginUpdates()
        self.tableView.endUpdates()

        // Might need to insert additional stuff here if scrolls
        // table in an unexpected way.  This scrolls to the bottom
        // of the table. (Though you might need something more
        // complicated if editing in the middle.)

        let scrollTo = self.tableView.contentSize.height - self.tableView.frame.size.height
        self.tableView.setContentOffset(CGPoint(x: 0, y: scrollTo), animated: false)

        UIView.setAnimationsEnabled(true)  // Re-enable animations.
}