Segue on DidSelectRowAtIndexPath from Custom DataSource/Delegate Swift - objective-c

Question

My setup:
`UITableViewController` (ComboViewController)
-> Several Static Cells
-> One Static Cell contains a dynamic `tableView`
I need to use a custom Delegate/DataSource because the dynamic tableView is embedded in the Static TableView within the TableViewController
This custom Delegate/DataSource looks like this:
class DataSource: NSObject, UITableViewDataSource, UITableViewDelegate {
// class variables
override init() {
super.init()
// initialize variables
}
//some data source/ delegate methods like number of rows, cellForRowAtIndexPath
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
var indexedCombos: NSDictionary?
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let comboVC: ComboInfoViewController = storyboard.instantiateViewControllerWithIdentifier("ComboInfo") as! ComboInfoViewController
comboVC.doSegue()
}
}
Within ComboViewController I have this:
class ComboInfoViewController: UITableViewController {
func doSegue() {
self.performSegueWithIdentifier("tosingle", sender: combListTable)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "tosingle" {
//do stuff
}
}
}
If the segue is modal I get this error:
Warning: Attempt to present SingleProductViewController on ComboInfoViewController whose view is not in the window hierarchy!
If the segue is push, then the prepareForSegue method gets called, but the viewController does not push! What is happening?
I've searched and searched. But I have no idea what could be resulting in this behavior.

Answer 1

When you create the ComboInfoViewController instance with this line,
let comboVC: ComboInfoViewController = storyboard.instantiateViewControllerWithIdentifier("ComboInfo") as! ComboInfoViewController
You're creating a new instance that is not the one you have on screen, and never will be, so that's why you get the error. It is very important that you understand this concept; understanding how view controllers are created, and how to get pointers to ones that already exist is fundamental to iOS programming.
However, in this case you don't even need to get a pointer to the one on screen, because you should connect the segue directly from the cell (the dynamic prototype), which means you won't need any code to execute it. You can delete the didSelectRowAtIndexPath method, and the doSegue method. You only need to implement prepareForSegue. If you need to pass information to the next controller based one which row was touched, you can do it like below. The table view controller code should now look like this (this is an update of the code in my answer to this question, Swift: TableView within Static UITableViewCell),
class ComboInfoViewController: UITableViewController {
#IBOutlet weak var staticTableView: UITableView!
#IBOutlet weak var dynamicTableView: UITableView!
var dataSource = DataSource()
override func viewDidLoad() {
super.viewDidLoad()
dynamicTableView.dataSource = dataSource
dynamicTableView.delegate = dataSource
}
override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
if indexPath.row != 1 {
return 44
}else{
return 250 // the second cell has the dynamic table view in it
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "tosingle" {
var cell = sender as! UITableViewCell
var indexPath = dynamicTableView.indexPathForCell(cell)
var dataPoint = dataSource.theData[indexPath!.row] // theData is the array used to populate the dynamic table view in the DataSource class
// pass dataPoint to the next view controller which you get from segue.destinationviewController
println(dataPoint)
}
}
}