Swift heightForRowAtIndexPath for views/labels with dynamic heights

Question

I am having a header named CollapsibleTableViewHeader and its height is dynamic based on the UILabels and UIViews contained inside it.

So, I have this function below -

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

        let header = self.tableView.dequeueReusableHeaderFooterViewWithIdentifier("header") as! CollapsibleTableViewHeader

        switch indexPath.row {
        case 0:
            if sections[indexPath.section].collapsed == true {
                return 0
            }
            else {

              return header.iconsViewHeightConstraint.constant + header.shortDescHeightConstraint.constant + header.validityDateHeightConstraint.constant + header.expiryAlertHeightConstraint.constant
            }

        default:
            return 0
        }

    }

In my else condition, I need to return the height of my header as the height of my row. So I added up all the elements inside my header and returning the value (CGFloat).

The height is returned as expected but the problem is the same height is applied to all the cells. For e.g. if the height value returned is 150.0, then the same 150.0 is being applied to all the cells out there irrespective of their individual heights.

How do I get the heights specific to each cell? indexPath is one critical thing to use, but I am not sure how to use it here.

Apologies, if the question is dumb! Please help

PS: I tried automaticDimension already but that doesn't help in anyway since I have these cells as collapse/expandable cells.

EDIT 1: Added viewForHeaderInSection code

// Header
    func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {

        let header = self.tableView.dequeueReusableHeaderFooterViewWithIdentifier("header") as! CollapsibleTableViewHeader

        if sections.count == 0 {
            self.tableView.userInteractionEnabled = false
            header.cornerRadiusView.layer.borderWidth = 0.0
            header.benefitAlertImage.hidden = true
            header.benefitAlertText.hidden = true
            header.amountLabel.hidden = true            
        }
        else {
            header.amountLabel.hidden = false
            header.cornerRadiusView.layer.borderWidth = 1.0
            self.tableView.userInteractionEnabled = true
            header.titleLabel.text = sections[section].name
            header.arrowImage.image = UIImage(named: "voucherDownArrow")
            header.setCollapsed(sections[section].collapsed)

            header.benefitDetailText2.text = sections[section].shortDesc
            header.benefitDetailText3.text = sections[section].untilDate

            header.section = section
            header.delegate = self

            if sections[section].collapsed == true {
                header.benefitAlertImage.hidden = true
                header.benefitAlertText.hidden = true
                header.commerceIconsContainerView.hidden = true

                for i in 0..<imagesArray.count {
                    imagesArray[i].image = UIImage(named: "")
                }

            }
            else {
                header.commerceIconsContainerView.hidden = false
                 if sections[section].items.count > 5 {
                    header.iconsViewHeightConstraint.constant = 74.0
                 }

                else {
                    header.iconsViewHeightConstraint.constant = 38.0
                }


                if sections[section].isNearExpiration == true {                 
                    header.benefitAlertImage.hidden = false
                    header.benefitAlertText.hidden = false
                }
                else {                  
                    header.benefitAlertImage.hidden = true
                    header.benefitAlertText.hidden = true
                }
            }
        }

        return header
    }

Answer 1

You need to store heights for each cell that you calculated in cellForRow method into an array, and then load then in heightForRowAtIndexPath function

For example:

var heights = [Int]()

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as!  Cell
    heights.append(calculationResult)
    return cell
}

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return heights[indexPath.row]
}

Answer 2

I'm not clear on what you're trying to do. You want to determine what the height of the header should be based on the elements inside it? If so, then you are using the wrong function. You should be using:

override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat { 
    if (isSectionCollapsed) {
        return 0
    } else {
         let sum = subView1.height + subView2.height + subView3.height
         return sum
    }
 }

Thats why all your rows are getting their height set to 150. If you are trying to hide rows if a section is collapsed, then you would also need a similar check for the rows in the function you listed:

override func tableView(_ tableView: UITableView, heightforRowatIndexPath section: Int) -> CGFloat {
    if (isSectionCollapsed) {
        return 0
    } else {
         // return row height for this tableViewCell
    }
 }

EDIT: Just saw your edit, and still think it's the same issue. That function is creating a header view, and the height of that will be returned from the ViewController by a call to heightForHeaderInSection, not heightforRowatIndexPath.