Swift: Unsatisfying constraints (auto layout) after tableView reloadSections - swift

Question

my problem looks like a weird behavior to me. I'm using Swift and iOS9+.
I've set up an UIViewController in storyboard with some views and a tableview. (Views are vertically above the tableview) All is set up properly with autolayout, no warnings and the UIViewController displays correctly.
In viewDidLoad() I request some table view data from an API and call tableView.reloadSections() after getting the response, the section fades correctly.
If I tap on a button in the section header, another view controller is presented where I can filter the requested data. After setting the filter, the view controller dismisses and the refreshVitalSigns(...) is called in the delegate.
Then again, I want to reload the table view section to only show the filtered data. When I call reloadSections() again, I get a lot of unsatisfying constraint warnings and the view is messed up, and I don't know why??????
With reloadData() everything works, but I only want to reload the section.
FYI: After requesting the API data, you have to scroll to see the whole table view content. If I scroll first, to see the whole content, and filter afterwards, also the reloadSections() works well! Obviously, it should also work without scrolling first...
Do you have any idea why this strange behavior happens?
I'm greatful for every hint!!!
Best
class JMProfileViewController: UIViewController {
/// Table view top spacing
#IBOutlet weak var tableViewTopSpacing: NSLayoutConstraint!
/// Table view
#IBOutlet var tableView: UITableView!
/// Attention view
#IBOutlet var attentionView: JMAttentionView?
var vitalSigns: [Items] = []
var data: [Items] = []
...
// View did load
override func viewDidLoad() {
super.viewDidLoad()
...
// Table view row height
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 44.0
// Register custom tableview header/footer views and cells
...
// Get table view data
let patientId = ...
getData(patientId)
}
/**
Get data
- parameter patientId: Patient ID
*/
func getData(patientId: Int) {
// Request
APIController.sharedInstance.getData(patientId: patientId) { response in
// Result handling
switch response {
case .Success(let result):
// Update vital signs
self.vitalSigns = result
self.data = result
// Reload data
self.tableView.beginUpdates()
self.tableView.reloadSections(NSIndexSet(index: 1), withRowAnimation: .Fade)
self.tableView.endUpdates()
case .Failure(let error):
print(error)
}
}
}
override func updateViewConstraints() {
super.updateViewConstraints()
// Set constraints depending on view's visibility
if let view = attentionView {
if view.hidden {
tableViewTopSpacing.constant = 0
} else {
tableViewTopSpacing.constant = view.bounds.height
}
}
}
// MARK: - Navigation
// Preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Data segue
if segue.identifier == SegueIdentifier.JMVitalSignsSegue.rawValue {
let vsvc = segue.destinationViewController as! JMVitalSignsViewController
vsvc.delegate = self
}
}
}
// MARK: - UITableViewDataSource
extension JMProfileViewController: UITableViewDataSource {
// Number of sections in table view
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 3
}
// Height for header in section
func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return section == 0 ? 0 : UITableViewAutomaticDimension
}
// Estimated height for header in section
func tableView(tableView: UITableView, estimatedHeightForHeaderInSection section: Int) -> CGFloat {
return section == 0 ? 0 : 27.0
}
// View for header in section
func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
switch section {
case 0:
// First section without header
return nil
case 1:
// Configure header
let header = tableView.dequeueReusableHeaderFooterViewWithIdentifier(CellIdentifier.JMTitleButtonHeaderView.rawValue) as! JMTitleButtonHeaderView
header.configure(NSLocalizedString("vitalSigns", comment: ""), buttonTarget: self, buttonImage: UIImage(named: "ic_filter_dark"), buttonAction: #selector(parameterButtonTapped(_:)))
return header
default:
// Configure header
let header = tableView.dequeueReusableHeaderFooterViewWithIdentifier(CellIdentifier.JMTitleButtonHeaderView.rawValue) as! JMTitleButtonHeaderView
header.configure(NSLocalizedString("others", comment: ""))
return header
}
}
/**
Vital signs button tapped
*/
func parameterButtonTapped(sender: UIButton) {
// Show vital signs view controller
self.performSegueWithIdentifier(SegueIdentifier.JMVitalSignsSegue.rawValue, sender: self)
}
// Number of rows in section
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
var rows = 0
switch section {
case 0:
// Diagnosis
rows = 1
break
case 1:
// Vital signs
rows = data.count > 0 ? data.count : 1
break
case 2:
// Others
rows = 3
break
default:
break
}
return rows
}
// Cell for row at indexpath
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
switch indexPath.section {
case 0:
let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier.JMSubtitleImageRightDetailCell.rawValue, forIndexPath: indexPath) as! JMSubtitleImageRightDetailCell
// Configure cell
...
return cell
case 1:
if data.count > 0 {
let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier.JMTitleThreeLabelsSubtitleCell.rawValue, forIndexPath: indexPath) as! JMTitleThreeLabelsSubtitleCell
// Configure cell
let item = data[indexPath.row]
cell.configure(item.caption, unit: item.unit, values: item.values)
cell.accessoryType = .DisclosureIndicator
return cell
} else {
let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier.JMBasicCell.rawValue, forIndexPath: indexPath)
// Configure cell
cell.textLabel?.text = NSLocalizedString("noData", comment: "")
cell.selectionStyle = .None
return cell
}
default:
let cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier.JMBasicCell.rawValue, forIndexPath: indexPath) as! JMDefaultCell
...
return cell
}
}
}
// MARK: - JMVitalSignsViewControllerDelegate
extension JMProfileViewController: JMVitalSignsViewControllerDelegate {
/**
Refresh vital signs
*/
func refreshVitalSigns(selectedItems: [Items]) {
print("Refresh vital signs")
var data: [Items] = []
for item in selectedItems {
for vitalItem in vitalSigns {
if item.match == vitalItem.match {
data.append(vitalItem)
break
}
}
}
self.data = data
// HERE IS MY PROBLEM
// tableView.beginUpdates()
// tableView.reloadSections(NSIndexSet(index: 1), withRowAnimation: .Fade)
// tableView.endUpdates()
tableView.reloadData()
}
}

Answer 1

Finally I've found a workaround.
I changed the UIViewController into a UITableViewController and added every custom UIView in the TableViewHeader (NOT Section header) with auto layout.
Now it works!