Cannot trigger didSelectRowAt in UITableViewDelegate - ios

Question

I'm trying to get the selected row in a table in Swift 4. The code presented for completeness, is as follows:
import UIKit
import WebKit
class FactorDetailsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
#IBOutlet weak var goalTitle: UILabel!
#IBOutlet weak var goalCopy: UITextView!
#IBOutlet weak var goalBenefit: UILabel!
#IBOutlet weak var goalName: UILabel!
#IBOutlet weak var graph: SimpleChart!
#IBOutlet weak var measurement: UILabel!
#IBOutlet weak var measurementRange: UILabel!
#IBOutlet weak var updated: UILabel!
#IBOutlet weak var factorCopy: UITextView!
#IBOutlet weak var impact: UILabel!
#IBOutlet weak var actionsTable: UITableView!
#IBOutlet weak var researchTable: UITableView!
#IBOutlet weak var scrollView: UIScrollView!
#IBOutlet weak var stackView: UIStackView!
var factorData : Factor?
var currentCategory : FactorCategory?
var recommendedActions : [Action] = []
var relatedResearch : [Research] = []
var goal : Goal?
var reading:Double?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.title = factorData?.factorName
measurement.text = String(reading!)
self.actionsTable.delegate = self
self.actionsTable.dataSource = self
self.actionsTable.isEditing = false
self.researchTable.delegate = self
self.researchTable.dataSource = self
self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Update", style: .done, target: self, action: #selector(addStuff))
goalCopy.text = goal?.copy
goalBenefit.text = "BIG BENEFIT"
goalTitle.text = goal?.title
for cat in (factorData?.categories)! {
let s = SimpleChartData(min : Double(cat.min), max : Double(cat.max), label : cat.label, label2 : String(cat.max))
if( graph.canLoad ) {
graph.data!.append(s)
}
}
graph.reading = reading!
// Pin the edges of the stack view to the edges of the scroll view that contains it
stackView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
stackView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
stackView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true
}
#objc func addStuff() {
// how does this work? Just takes you to the quiz again
let storyboard = UIStoryboard(name: "12Factor", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "AllQuestionViewController") as UIViewController
present(vc, animated: true, completion: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func configure( factor : Factor )
{
factorData = factor
let mirrored_object = Mirror(reflecting: HRResponses.shared)
reading = 1.0
for (_, attr) in mirrored_object.children.enumerated() {
if let property_name = attr.label as String? {
if factorData?.responseField == property_name {
if let a = attr.value as? String, let aDouble = Double(a) {
reading = aDouble
}
}
}
}
currentCategory = factor.categories.first( where: {$0.min < reading! && $0.max > reading! })
for aind in (currentCategory?.actions)! {
let act = SignalModel.model.actions.first( where: {$0.id == aind})
recommendedActions.append(act!)
}
for rind in (currentCategory?.research)! {
let act = SignalModel.model.research.first( where: {$0.id == rind})
relatedResearch.append(act!)
}
goal = SignalModel.model.goals.first( where: {$0.id == currentCategory?.goals[0]})
}
func tableView(_ tableView: UITableView,
willSelectRowAt indexPath: IndexPath) -> IndexPath? {
print("works?")
return nil
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
{
if tableView == self.actionsTable {
let vc : ActionViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ActionViewController") as! ActionViewController
navigationController?.pushViewController(vc, animated: true)
}
if tableView == self.researchTable {
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Return the number of items in the sample data structure.
var count:Int?
if tableView == self.actionsTable {
count = currentCategory?.actions.count
}
if tableView == self.researchTable {
count = currentCategory?.research.count
}
return count!
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell:UITableViewCell?
if tableView == self.actionsTable {
cell = tableView.dequeueReusableCell(withIdentifier: "ActionCell", for: indexPath as IndexPath)
let action = recommendedActions[indexPath.row]
(cell as! ActionCell).configure(a:action)
}
if tableView == self.researchTable {
cell = tableView.dequeueReusableCell(withIdentifier: "ResearchCell", for: indexPath as IndexPath)
let research = relatedResearch[indexPath.row]
(cell as! ResearchCell).configure(r:research)
}
return cell!
}
}
Now, that's too much code. The relevant parts are here:
self.actionsTable.delegate = self // yes, this is the delegate
self.actionsTable.dataSource = self
self.actionsTable.isEditing = false // no, we're not editing
As I understand it, this should be enough to have selections in the actionsTable trigger the
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
method. However, nothing happens. The other UITableViewDelegate methods are called, so this controller is the delegate for this table, however this one method is not ever triggered. Reading through the Apple documentation here I see that the method isn’t called when the table view is in editing mode (that is, the isEditing property of the table view is set to true), but my table isn't in editing mode. Is there something else that could be going wrong with my table that wouldn't allow it to send an event to a UITableViewDelegate? I suspect that this has something to do with the table being inside a UIScrollView, which I've read isn't best practice, but with the design I've been given, is non-negotiable sadly.

Answer 1

Your problem is not the delegate, all of that code is good. Your problem is that the parent scroll view is consuming the taps, not the table view. Remember, UITableView is a direct subclass of UIScrollView so placing a table view inside a scroll view is no different than placing a scroll view within a scroll view. UITableView has all of the default scroll view delegates built into it so just use those.
You should not embed UIWebView or UITableView objects in UIScrollView
objects. If you do so, unexpected behavior can result because touch
events for the two objects can be mixed up and wrongly handled.
Apple dox
I know it's not the answer you wanted because this wasn't your doing but I personally would not proceed with a hack. I would restructure the code and trim the controller down to one scroll view.