get indexPath of UITableViewCell on click of Button from Cell

Use Delegates:

MyCell.swift:

import UIKit

//1. delegate method
protocol MyCellDelegate: AnyObject {
    func btnCloseTapped(cell: MyCell)
}

class MyCell: UICollectionViewCell {
    @IBOutlet var btnClose: UIButton!

    //2. create delegate variable
    weak var delegate: MyCellDelegate?

    //3. assign this action to close button
    @IBAction func btnCloseTapped(sender: AnyObject) {
        //4. call delegate method
        //check delegate is not nil with `?`
        delegate?.btnCloseTapped(cell: self)
    }
}

MyViewController.swift:

//5. Conform to delegate method
class MyViewController: UIViewController, MyCellDelegate, UITableViewDataSource,UITableViewDelegate {

    //6. Implement Delegate Method
    func btnCloseTapped(cell: MyCell) {
        //Get the indexpath of cell where button was tapped
        let indexPath = self.collectionView.indexPathForCell(cell)
        print(indexPath!.row)
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCellWithIdentifier("MyCell") as! MyCell
        //7. delegate view controller instance to the cell
        cell.delegate = self

        return cell
    }
}

How to get cell indexPath for tapping button in Swift 4 with button selector

@objc func buttonClicked(_sender:UIButton){

 let buttonPosition = sender.convert(CGPoint.zero, to: self.tableView)
 let indexPath = self.tableView.indexPathForRow(at:buttonPosition)
 let cell = self.tableView.cellForRow(at: indexPath) as! UITableViewCell
 print(cell.itemLabel.text)//print or get item
}

Try with the best use of swift closures : Simple, Quick & Easy.

In cellForRowAtIndexPath method:

let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCellIdentifier", for: indexPath) as! CustomCell

cell.btnTick.mk_addTapHandler { (btn) in
     print("You can use here also directly : \(indexPath.row)")
     self.btnTapped(btn: btn, indexPath: indexPath)
}

Selector Method for external use out of cellForRowAtIndexPath method:

func btnTapped(btn:UIButton, indexPath:IndexPath) {
    print("IndexPath : \(indexPath.row)")
}

Extension for UIButton :

extension UIButton {

    private class Action {
        var action: (UIButton) -> Void

        init(action: @escaping (UIButton) -> Void) {
            self.action = action
        }
    }

    private struct AssociatedKeys {
        static var ActionTapped = "actionTapped"
    }

    private var tapAction: Action? {
        set { objc_setAssociatedObject(self, &AssociatedKeys.ActionTapped, newValue, .OBJC_ASSOCIATION_RETAIN) }
        get { return objc_getAssociatedObject(self, &AssociatedKeys.ActionTapped) as? Action }
    }


    @objc dynamic private func handleAction(_ recognizer: UIButton) {
        tapAction?.action(recognizer)
    }


    func mk_addTapHandler(action: @escaping (UIButton) -> Void) {
        self.addTarget(self, action: #selector(handleAction(_:)), for: .touchUpInside)
        tapAction = Action(action: action)

    }
}

In Swift 4 , just use this:

func buttonTapped(_ sender: UIButton) {

    let buttonPostion = sender.convert(sender.bounds.origin, to: tableView)

    if let indexPath = tableView.indexPathForRow(at: buttonPostion) {
        let rowIndex =  indexPath.row
    }
}