将表格视图单元格扩展到内容的高度

Question

My ViewController has a tableView inside it, and every cell within the tableView has a textView that displays poems. Some poems are long and some are short. I made some code to expand the UITableViewCell when tapped so that the user could focus on reading only one poem and the other ones would be hidden.

This is my code:

@IBOutlet weak var poemasTableView: UITableView!
    var selectedRowIndex = -1

 func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        if indexPath.row == selectedRowIndex {
            return 240 //Expanded
        }
        return 55 //Not expanded
    }

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if selectedRowIndex == indexPath.row {
            selectedRowIndex = -1
        } else {
            selectedRowIndex = indexPath.row
        }
        tableView.reloadRows(at: [indexPath], with: .automatic)
    }

It is working fine, however I want to do something else. When the cell is tapped, I want it to expand in order to fit the content of the textView. So, for example, if a poem is too large than the new height should be 320 but if it is shorter, it should be 150 and so on.

How could I do this?

Answer 1

You can calculate the bounding box of the complete poem using boundingRectWithSize . And then you would assign the calculated height to the height of the row.

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    if indexPath.row == selectedRowIndex {
        // Expanded
        let poem: String = poems[indexPath.row]
        let size = CGSize(width: poemasTableView.frame.width, height: .greatestFiniteMagnitude)
        let rectangle: CGRect = NSString(string: poem).boundingRect(with: size,
                             options: .usesLineFragmentOrigin,
                             attributes: [.font: UIFont.systemFont(ofSize: 16)],
                             context: nil)
        let maximum_height: CGFloat = 1366
        let rowHeight: CGFloat = min(rectangle.height, maximum_height)
        return rowHeight
    }
    return 55 //Not expanded
}