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

Question

I have a case in which I have to reload only height of a UITableViewCell.
but if I call the function
tableView.reloadRowsAtIndexPaths([NSIndexPath(forRow: webView.tag, inSection: 0)], withRowAnimation: .Automatic)
it reloads the height as well as the data of the cell.
How can i just control the height of cell in Swift?
This is my cellForRow block :
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if indexPath.row == 0 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! CustomTableViewCell1
cell.heading.text = headerText
return cell
}
else if indexPath.row == 1 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell2", forIndexPath: indexPath) as! CustomTableViewCell2
ImageLoader.sharedLoader.imageForUrl(self.headerImage , completionHandler:{(image: UIImage?, url: String) in
cell.mainImage.image = image
})
return cell
}
else if indexPath.row == 2 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell3", forIndexPath: indexPath) as! CustomTableViewCell3
//cell.aurthorImage.image = UIImage(named : "obama")
ImageLoader.sharedLoader.imageForUrl(self.headerImage , completionHandler:{(image: UIImage?, url: String) in
cell.aurthorImage.image = image
})
cell.aurthorImage.tag = aurthorID
cell.aurthorImage.layer.cornerRadius = cell.aurthorImage.frame.height/2
cell.aurthorImage.clipsToBounds = true
cell.aurthorImage.userInteractionEnabled = true
cell.aurthorImage.addGestureRecognizer(aurthorImageTapRecignizer)
cell.aurthorName.text = self.authorName
cell.time.text = self.time
self.followButton = cell.followButton
return cell
}
else if indexPath.row == 3 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell4", forIndexPath: indexPath) as! CustomTableViewCell4
let htmlHeight = contentHeights[indexPath.row]
cell.webElement.tag = indexPath.row
cell.webElement.delegate = self
cell.webElement.loadHTMLString(HTMLContent, baseURL: nil)
cell.webElement.frame = CGRectMake(0, 0, cell.frame.size.width, htmlHeight)
return cell
}
else if indexPath.row == 4 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! CustomTableViewCell1
cell.heading.text = "Related Posts"
return cell
}
else if indexPath.row == 5{
let cell = tableView.dequeueReusableCellWithIdentifier("cell6", forIndexPath: indexPath) as! CustomTableViewCell6
return cell
}
else if indexPath.row == 6 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! CustomTableViewCell1
cell.heading.text = "Comments"
return cell
}
else if indexPath.row == 7 {
let cell = tableView.dequeueReusableCellWithIdentifier("cell5", forIndexPath: indexPath) as! CustomTableViewCell5
let htmlHeight = contentHeights[indexPath.row]
self.commentSection = cell.commentsView
self.commentSection.tag = indexPath.row
self.commentSection.delegate = self
let url = NSURL(string: commentsURL)
let requestObj = NSURLRequest(URL: url! )
self.commentSection.loadRequest(requestObj)
self.commentSection.frame = CGRectMake(0, 0, cell.frame.size.width, htmlHeight)
commentSectionDidNotLoad = false
return cell
}
else {
let cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath) as! CustomTableViewCell1
cell.heading.text = headerText
return cell
}

Answer 1

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

Answer 2

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()

Answer 3

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)
}
}

Answer 4

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.