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Swift: How to reload row height in UITableViewCell without reloading data

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死守一世寂寞
死守一世寂寞 2020-12-25 13:20

I have a case in which I have to reload only height of a UITableViewCell.

but if I call the function 

tableView.reloadRowsAtIndexPaths([
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  • 庸人自扰
    2020-12-25 13:37

    About your question for example, to give a specific height dimension :

    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
  if indexPath.row == 3 {
    return 50.0
  }

  return 72.0
}

    But I think you have a webView inside a cell so, generally, to calculate the dynamic height of a UITableViewCell with a UIWebView: (this example have two webViews)

    class MyTableViewController: UITableViewController, UIWebViewDelegate
{
    var content : [String] = ["<!DOCTYPE html><html><head><title>Page Title</title></head><body><h1>My First Heading</h1><p>My first paragraph</p></body></html>", "<HTML><HEAD><TITLE>Coca-Cola</TITLE></HEAD><BODY>In Chinese, Coca-Cola means Bite the Wax Tadpole</BODY></HTML>"]
    var contentHeights : [CGFloat] = [0.0, 0.0]

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
    {
        let cell = tableView.dequeueReusableCellWithIdentifier("myCustomCell", forIndexPath: indexPath) as! MyCustomCell
        let htmlString = content[indexPath.row]
        let htmlHeight = contentHeights[indexPath.row]

        cell.webView.tag = indexPath.row
        cell.webView.delegate = self
        cell.webView.loadHTMLString(htmlString, baseURL: nil)
        cell.webView.frame = CGRectMake(0, 0, cell.frame.size.width, htmlHeight)
        return cell
    }
    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat
    {
        return contentHeights[indexPath.row]
    }
    func webViewDidFinishLoad(webView: UIWebView)
    {
        if (contentHeights[webView.tag] != 0.0)
        {
            // height knowed, no need to reload cell
            return
        }
        contentHeights[webView.tag] = webView.scrollView.contentSize.height
        tableView.reloadRowsAtIndexPaths([NSIndexPath(forRow: webView.tag, inSection: 0)], withRowAnimation: .Automatic)
    }
}
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  • 盖世英雄少女心
    2020-12-25 13:40

    start an update of the tableview and then end it without changing anything.

    tableView.beginUpdates()
tableView.endUpdates()

    This should make the tableview set the new height

    You can regulate the height by either implementing the (a)heightForRowAtIndexPath with logic setting the heights or (b)with auto layout and automatic tableview row height

    A.

    override func tableView(tableView: UITableView!, heightForRowAtIndexPath indexPath: NSIndexPath!) -> CGFloat {
     if [your condition, row == 5 in your comment] {
          return 100
     } else {
         return 40
     }
}

    Whenever you want to change the height you would just call these two rows

    tableView.beginUpdates()
tableView.endUpdates()

    B.

    in viewDidLoad

    tableView.estimatedRowHeight = 40.0
tableView.rowHeight = UITableViewAutomaticDimension

    and then you can just expose the layout constraint that set's the cells height and access it to set the height when you want

    cell.heightConstraint.constant = 100
tableView.beginUpdates()
tableView.endUpdates()
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  • 灰色年华
    2020-12-25 13:48

    You can use this code to update the cell's height without reloading their data:

    tableView.beginUpdates()
tableView.endUpdates()

    You can also use this method followed by the endUpdates method to animate the change in the row heights without reloading the cell.

    UITableView Class Reference

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  • 情话喂你
    2020-12-25 13:53

    You can use the view height constraint in the cell, by updating the view in cell height you can update the specific cell height.

    let height = cell.Height_constraint.constant
cell.Height_constraint.constant = height + 200 //200 you can use any number

    Height_constraint: is the height constraint of subView in my cell.

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