Detecting which UIButton was pressed in a UITableView
In Apple's Accessory sample the following method is used:
[button addTarget:self action:@selector(checkButtonTapped:) forControlEvents:UIControlEventTouchUpInside];
Then in touch handler touch coordinate retrieved and index path is calculated from that coordinate:
- (void)checkButtonTapped:(id)sender
{
CGPoint buttonPosition = [sender convertPoint:CGPointZero toView:self.tableView];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:buttonPosition];
if (indexPath != nil)
{
...
}
}
I found the method of using the superview's superview to obtain a reference to the cell's indexPath worked perfectly. Thanks to iphonedevbook.com (macnsmith) for the tip link text
-(void)buttonPressed:(id)sender {
UITableViewCell *clickedCell = (UITableViewCell *)[[sender superview] superview];
NSIndexPath *clickedButtonPath = [self.tableView indexPathForCell:clickedCell];
...
}
Here's how I do it. Simple and concise:
- (IBAction)buttonTappedAction:(id)sender
{
CGPoint buttonPosition = [sender convertPoint:CGPointZero
toView:self.tableView];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:buttonPosition];
...
}
With Swift 4.2 and iOS 12, you can choose one the 5 following complete examples in order to solve your problem.
#1. Using UIView
's convert(_:to:)
and UITableView
's indexPathForRow(at:)
import UIKit
private class CustomCell: UITableViewCell {
let button = UIButton(type: .system)
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
button.setTitle("Tap", for: .normal)
contentView.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
import UIKit
class TableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
cell.button.addTarget(self, action: #selector(customCellButtonTapped), for: .touchUpInside)
return cell
}
@objc func customCellButtonTapped(_ sender: UIButton) {
let point = sender.convert(CGPoint.zero, to: tableView)
guard let indexPath = tableView.indexPathForRow(at: point) else { return }
print(indexPath)
}
}
#2. Using UIView
's convert(_:to:)
and UITableView
's indexPathForRow(at:)
(alternative)
This is an alternative to the previous example where we pass nil
to the target
parameter in addTarget(_:action:for:)
. This way, if the first responder does not implement the action, it will be send to the next responder in the responder chain until until a proper implementation is found.
import UIKit
private class CustomCell: UITableViewCell {
let button = UIButton(type: .system)
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
button.setTitle("Tap", for: .normal)
button.addTarget(nil, action: #selector(TableViewController.customCellButtonTapped), for: .touchUpInside)
contentView.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
import UIKit
class TableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
return cell
}
@objc func customCellButtonTapped(_ sender: UIButton) {
let point = sender.convert(CGPoint.zero, to: tableView)
guard let indexPath = tableView.indexPathForRow(at: point) else { return }
print(indexPath)
}
}
#3. Using UITableView
's indexPath(for:)
and delegate pattern
In this example, we set the view controller as the delegate of the cell. When the cell's button is tapped, it triggers a call to the appropriate method of the delegate.
import UIKit
protocol CustomCellDelegate: AnyObject {
func customCellButtonTapped(_ customCell: CustomCell)
}
class CustomCell: UITableViewCell {
let button = UIButton(type: .system)
weak var delegate: CustomCellDelegate?
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
button.setTitle("Tap", for: .normal)
button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
contentView.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
@objc func buttonTapped(sender: UIButton) {
delegate?.customCellButtonTapped(self)
}
}
import UIKit
class TableViewController: UITableViewController, CustomCellDelegate {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
cell.delegate = self
return cell
}
// MARK: - CustomCellDelegate
func customCellButtonTapped(_ customCell: CustomCell) {
guard let indexPath = tableView.indexPath(for: customCell) else { return }
print(indexPath)
}
}
#4. Using UITableView
's indexPath(for:)
and a closure for delegation
This is an alternative to the previous example where we use a closure instead of a protocol-delegate declaration to handle the button tap.
import UIKit
class CustomCell: UITableViewCell {
let button = UIButton(type: .system)
var buttontappedClosure: ((CustomCell) -> Void)?
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
button.setTitle("Tap", for: .normal)
button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
contentView.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
@objc func buttonTapped(sender: UIButton) {
buttontappedClosure?(self)
}
}
import UIKit
class TableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
cell.buttontappedClosure = { [weak tableView] cell in
guard let indexPath = tableView?.indexPath(for: cell) else { return }
print(indexPath)
}
return cell
}
}
#5. Using UITableViewCell
's accessoryType
and UITableViewDelegate
's tableView(_:accessoryButtonTappedForRowWith:)
If your button is a UITableViewCell
's standard accessory control, any tap on it will trigger a call to UITableViewDelegate
's tableView(_:accessoryButtonTappedForRowWith:)
, allowing you to get the related index path.
import UIKit
private class CustomCell: UITableViewCell {
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
accessoryType = .detailButton
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
import UIKit
class TableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
return cell
}
override func tableView(_ tableView: UITableView, accessoryButtonTappedForRowWith indexPath: IndexPath) {
print(indexPath)
}
}