Can I change height of UITableViewCell real-time?

Question

I have UITableViewCell and inside of that cell I have a UITextView. When I will change text of UITextView I want to change cell height real time?

How can I do that? Thanks.

Answer 1

The main idea of this solution is to calculate the textView's height and assigns it to its row.

Note: this is Swift 3 code:

class ViewController: UIViewController {

    // array containing rows heights:
    var rowHeights = [CGFloat]()

    @IBOutlet weak var tableView: UITableView!
    override func viewDidLoad() {
        super.viewDidLoad()

        // fill it with default values of row heights
        for _ in 1...10 {
            rowHeights.append(44)
        }
    }
}

extension ViewController: UITableViewDataSource, UITableViewDelegate {
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return rowHeights[indexPath.row]
    }


    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // return the actual number of your rows...
        return 10
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "TextViewTableViewCell") as! TextViewTableViewCell

        // assgin the tag of current text view to use for determining the current cell's height
        cell.textView.tag = indexPath.row

        cell.textView.delegate = self

        return cell
    }
}

extension ViewController: UITextViewDelegate {
    func textViewDidChange(_ textView: UITextView) {

        // calculate the current height and append it in the rowHeights depends on the textView's tag. Add your the textView fontSize instead of 15
        rowHeights[textView.tag] = (textView.text?.heightWithConstrainedWidth(width: tableView.frame.size.width, font: UIFont.systemFont(ofSize: 15)))!

        // for updating the tableView appearence (don't use "reloadData", it will resignFirstResponder the textView)
        tableView.beginUpdates()
        tableView.endUpdates()

        textView.setContentOffset(CGPoint.zero, animated: true)

        //textView.becomeFirstResponder()
    }
}

extension String {
    // this method calculates the height of string depending on your view width and font
    func heightWithConstrainedWidth(width: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: width, height: .greatestFiniteMagnitude)
        let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)

        return boundingBox.height
    }
}

CustomTableViewCell:

class TextViewTableViewCell: UITableViewCell {
    @IBOutlet weak var textView: UITextView!
}

The output should looks like this:

Hope That Helped.

Answer 2

If you are using auto layout to calculate your cells height, I think you just have to use reloadData() method on your tableView.

Answer 3

you need to set autolayout of UITableviewCell as per below link :

Using Auto Layout in UITableView for dynamic cell layouts & variable row heights

after this you have to reload UITableViewCell as per your needs using below link :

Reload specific UITableView cell in iOS

Answer 4

Reference from : Using Auto Layout in UITableView for dynamic cell layouts & variable row heights

You need to calculate height of cell after the auto layout do its part I mean after arranging the inner views width/height based on text provided.

Follow the solution:

First add UITableView delegate method below in view controller,

- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath {
    return UITableViewAutomaticDimension;
}

Calculate cell's height in heightForRowAtIndexPath: delegate method:

* THIS IS IMPORTANT*: Do remember that assign cell label's and textView's values same like you did in cellForRowAtIndexPath delegate method.

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
 NSString *cellIdentifier = [NSString stringWithFormat:@"CustomCell%d%d",(int)indexPath.section, (int)indexPath.row];

    CustomCell *cell = (CustomCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    if (cell == nil) {
        cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }

    // Set cell label text same like you did in `cellForRowAtIndexPath`
    // For example
    NSString *name = [self.dataArray objectAtIndex:indexPath.row];
    cell.nameLabel.text = name;
    cell.textView.text = @"This is long text.....";

    [cell setNeedsUpdateConstraints];
    [cell updateConstraintsIfNeeded];
    cell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(tableView.bounds), CGRectGetHeight(cell.bounds));

    [cell setNeedsLayout];
    [cell layoutIfNeeded];

    CGFloat height = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
    height += 5;

    return height;
}

Now if you have created CustomCell add below constraints in cell's initWithStyle: method

// Other controls initialisation and creation code
// ....
// TextView control setup

[self.textView setTranslatesAutoresizingMaskIntoConstraints:NO];
// Above line is very important otherwise below constraint wont work
// Because by default it uses auto size constraints


// Other controls constraints
// ....

[self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[textView]-10-|" options:0 metrics:nil views:@{@"textView" : self.textView}]];

NSLayoutConstraint *pinToBottom = [NSLayoutConstraint constraintWithItem:self.textView
                                                               attribute:NSLayoutAttributeBottom
                                                               relatedBy:NSLayoutRelationEqual
                                                                  toItem:self.contentView
                                                               attribute:NSLayoutAttributeBottom
                                                              multiplier:1
                                                                constant:0];
[self.contentView addConstraint:pinToBottom];

And add below delegate method

- (void)layoutSubviews {
    [super layoutSubviews];

    [self.contentView setNeedsLayout];
    [self.contentView layoutIfNeeded];

    self.textView.preferredMaxLayoutWidth = CGRectGetWidth(self.textView.frame);
}

But if you have not created custom cell and you are using cell from Storyboard, add bottom constraint to your superView (cell's content view).

Answer 5

Call This method from cellForRowAtIndexPath Delegate

(CGSize)attributedText:(NSAttributedString *)text sizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size 
{
        return  [self textViewHeightForAttributedText:text constrainedToSize:size];
}

This method will give you the height of your cell.

(CGSize)textViewHeightForAttributedText: (NSAttributedString*)text constrainedToSize:(CGSize)size 
   {
        UITextView *calculationView = [[UITextView alloc] init];
        [calculationView setAttributedText:text];
        CGSize size1 = [calculationView sizeThatFits:size];
        return size1;
   }

use this statement in cellForRowAtIndexPath

CGSize  textSize = {tableView.frame.size.width-70, 10000.0 };
CGSize size1 =[self attributedText:attrString sizeWithFont:[UIFont fontWithName:@"HelveticaNeue-Light" size:14] constrainedToSize:textSize];