Reputation: 1645
I have a tableview with buttons and I want to use the indexpath.row when one of them is tapped. This is what I currently have, but it always is 0
var point = Int()
func buttonPressed(sender: AnyObject) {
let pointInTable: CGPoint = sender.convertPoint(sender.bounds.origin, toView: self.tableView)
let cellIndexPath = self.tableView.indexPathForRowAtPoint(pointInTable)
println(cellIndexPath)
point = cellIndexPath!.row
println(point)
}
Upvotes: 119
Views: 163647
Reputation: 4951
To handle button taps in a UITableViewCell
or its subclasses I would definitely suggest delegation
pattern which is covered above to have some Separation of Concerns for both the cell
and the viewController
.
However, if for some other reasons you need to find the indexPath
of a cell when a button or any other UIView subclass inside it is tapped I would suggest using class extensions. This way you could achieve Interface Segregation and SOLIDify your code a little bit.
Problem with other solutions:
Tags: as suggested above they are fragile when you insert or delete a row
Using superView property: It is not neat by any means. How many layers of views should you pass to reach the cell
itself or the containing tableView
. You may end up having something like this in your code which is not beautiful :
let tableView = view.superView.superView.superView.superView
Create an extension on UIResponder
to get the first superView
of a view
of type T
in the view hierarchy.
extension UIResponder {
func next<T: UIResponder>(_ type: T.Type) -> T? {
self.next as? T ?? self.next?.next(type)
}
}
This will iterate the whole view hierarchy until it finds a view of the given type or the end of the hierarchy in which it will return nil.
Write an extension on UITableViewCell
and use the next
method to find the tableView
to which the cell belongs and the indexPath
of the cell.
extension UITableViewCell {
var tableView: UITableView? {
return next(UITableView.self)
}
var indexPath: IndexPath? {
return tableView?.indexPathForRow(at: self.center)
//return tableView?.indexPath(for: self) // Note: This will return nil if the cell is not visible yet
}
}
Use it wherever you want like this.
func buttonTapped(_ sender: UIButton) {
guard let cell = sender.next(YourCellType.self), let indexPath = cell.indexPath else {
return
}
// Use indexPath here
}
Upvotes: 1
Reputation: 131398
@Paulw11's answer of setting up a custom cell type with a delegate property that sends messages to the table view is a good way to go, but it requires a certain amount of work to set up.
I think walking the table view cell's view hierarchy looking for the cell is a bad idea. It is fragile - if you later enclose your button in a view for layout purposes, that code is likely to break.
Using view tags is also fragile. You have to remember to set up the tags when you create the cell, and if you use that approach in a view controller that uses view tags for another purpose you can have duplicate tag numbers and your code can fail to work as expected.
I have created an extension to UITableView that lets you get the indexPath for any view that is contained in a table view cell. It returns an Optional
that will be nil if the view passed in actually does not fall within a table view cell. Below is the extension source file in it's entirety. You can simply put this file in your project and then use the included indexPathForView(_:)
method to find the indexPath that contains any view.
//
// UITableView+indexPathForView.swift
// TableViewExtension
//
// Created by Duncan Champney on 12/23/16.
// Copyright © 2016-2017 Duncan Champney.
// May be used freely in for any purpose as long as this
// copyright notice is included.
import UIKit
public extension UITableView {
/**
This method returns the indexPath of the cell that contains the specified view
- Parameter view: The view to find.
- Returns: The indexPath of the cell containing the view, or nil if it can't be found
*/
func indexPathForView(_ view: UIView) -> IndexPath? {
let center = view.center
let viewCenter = self.convert(center, from: view.superview)
let indexPath = self.indexPathForRow(at: viewCenter)
return indexPath
}
}
To use it, you can simply call the method in the IBAction for a button that's contained in a cell:
func buttonTapped(_ button: UIButton) {
if let indexPath = self.tableView.indexPathForView(button) {
print("Button tapped at indexPath \(indexPath)")
}
else {
print("Button indexPath not found")
}
}
(Note that the indexPathForView(_:)
function will only work if the view object it's passed is contained by a cell that's currently on-screen. That's reasonable, since a view that is not on-screen doesn't actually belong to a specific indexPath; it's likely to be assigned to a different indexPath when it's containing cell is recycled.)
You can download a working demo project that uses the above extension from Github: TableViewExtension.git
Upvotes: 21
Reputation: 7028
Extend UITableView to create function that get indexpath for a view:
extension UITableView {
func indexPath(for view: UIView) -> IndexPath? {
self.indexPathForRow(at: view.convert(.zero, to: self))
}
}
How to use:
let row = tableView.indexPath(for: sender)?.row
Upvotes: 0
Reputation: 1968
Solution:
You have a button (myButton) or any other view in cell. Assign tag in cellForRowAt like this
cell.myButton.tag = indexPath.row
Now in you tapFunction or any other. Fetch it out like this and save it in a local variable.
currentCellNumber = (sender.view?.tag)!
After this you can use anywhere this currentCellNumber to get the indexPath.row of selected button.
Enjoy!
Upvotes: 11
Reputation: 498
USING A SINGLE TAG FOR ROWS AND SECTIONS
There is a simple way to use tags for transmitting the row/item AND the section of a TableView/CollectionView at the same time.
Encode the IndexPath for your UIView.tag in cellForRowAtIndexPath :
buttonForCell.tag = convertIndexPathToTag(with: indexPath)
Decode the IndexPath from your sender in your target selector:
@IBAction func touchUpInsideButton(sender: UIButton, forEvent event: UIEvent) {
var indexPathForButton = convertTagToIndexPath(from: sender)
}
Encoder and Decoder:
func convertIndexPathToTag(indexPath: IndexPath) -> Int {
var tag: Int = indexPath.row + (1_000_000 * indexPath.section)
return tag
}
func convertTagToIndexPath(from sender: UIButton) -> IndexPath {
var section: Int = Int((Float(sender.tag) / 1_000_000).rounded(.down))
var row: Int = sender.tag - (1_000_000 * section)
return IndexPath(row: row, section: section)
}
Provided that you don’t need more than 4294967296 rows/items on a 32bit device ;-) e.g.
—-
WARNING: Keep in mind that when deleting or inserting rows/items in your TableView/CollectionView you have to reload all rows/items after your insertion/deletion point in order to keep the tag numbers of your buttons in sync with your model.
—-
Upvotes: 0
Reputation: 1744
Very Simple getting Index Path swift 4, 5
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! Cell
cell.btn.tag = indexPath.row
cell.btn.addTarget(self, action: "buttonTapped:", forControlEvents:
UIControlEvents.TouchUpInside)
How to get IndexPath Inside Btn Click :
func buttonTapped(_ sender: UIButton) {
print(sender.tag)
}
Upvotes: 4
Reputation: 2901
Swift 4 and 5
For example, you have a UITableViewCell
with name MyCell
class MyCell: UITableViewCell {
var delegate:MyCellDelegate!
@IBAction private func myAction(_ sender: UIButton){
delegate.didPressButton(cell: self)
}
}
Now create a protocol
protocol MyCellDelegate {
func didPressButton(cell: UITableViewCell)
}
Next step, create an Extension of UITableView
extension UITableView {
func returnIndexPath(cell: UITableViewCell) -> IndexPath?{
guard let indexPath = self.indexPath(for: cell) else {
return nil
}
return indexPath
}
}
In your UIViewController
implement the protocol MyCellDelegate
class ViewController: UIViewController, MyCellDelegate {
func didPressButton(cell: UITableViewCell) {
if let indexpath = self.myTableView.returnIndexPath(cell: cell) {
print(indexpath)
}
}
}
In UIViewController
override func viewDidLoad() {
super.viewDidLoad()
//using the same `UITableView extension` get the IndexPath here
didPressButton = { cell in
if let indexpath = self.myTableView.returnIndexPath(cell: cell) {
print(indexpath)
}
}
}
var didPressButton: ((UITableViewCell) -> Void)
class MyCell: UITableViewCell {
@IBAction private func myAction(_ sender: UIButton){
didPressButton(self)
}
}
Note:- if you want to get
UICollectionView
indexPath you can use thisUICollectionView extension
and repeat the above steps
extension UICollectionView {
func returnIndexPath(cell: UICollectionViewCell) -> IndexPath?{
guard let indexPath = self.indexPath(for: cell) else {
return nil
}
return indexPath
}
}
Upvotes: 2
Reputation: 595
// CustomCell.swift
protocol CustomCellDelegate {
func tapDeleteButton(at cell: CustomCell)
}
class CustomCell: UICollectionViewCell {
var delegate: CustomCellDelegate?
fileprivate let deleteButton: UIButton = {
let button = UIButton(frame: .zero)
button.setImage(UIImage(named: "delete"), for: .normal)
button.addTarget(self, action: #selector(deleteButtonTapped(_:)), for: .touchUpInside)
button.translatesAutoresizingMaskIntoConstraints = false
return button
}()
@objc fileprivate func deleteButtonTapped(_sender: UIButton) {
delegate?.tapDeleteButton(at: self)
}
}
// ViewController.swift
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: customCellIdentifier, for: indexPath) as? CustomCell else {
fatalError("Unexpected cell instead of CustomCell")
}
cell.delegate = self
return cell
}
}
extension ViewController: CustomCellDelegate {
func tapDeleteButton(at cell: CustomCell) {
// Here we get the indexPath of the cell what we tapped on.
let indexPath = collectionView.indexPath(for: cell)
}
}
Upvotes: 0
Reputation: 1335
In my case i have multiple sections and both the section and row index is vital, so in such a case i just created a property on UIButton which i set the cell indexPath like so:
fileprivate struct AssociatedKeys {
static var index = 0
}
extension UIButton {
var indexPath: IndexPath? {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.index) as? IndexPath
}
set {
objc_setAssociatedObject(self, &AssociatedKeys.index, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
}
Then set the property in cellForRowAt like this :
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! Cell
cell.button.indexPath = indexPath
}
Then in the handleTapAction you can get the indexPath like this :
@objc func handleTapAction(_ sender: UIButton) {
self.selectedIndex = sender.indexPath
}
Upvotes: 0
Reputation: 114773
My approach to this sort of problem is to use a delegate protocol between the cell and the tableview. This allows you to keep the button handler in the cell subclass, which enables you to assign the touch up action handler to the prototype cell in Interface Builder, while still keeping the button handler logic in the view controller.
It also avoids the potentially fragile approach of navigating the view hierarchy or the use of the tag
property, which has issues when cells indexes change (as a result of insertion, deletion or reordering)
CellSubclass.swift
protocol CellSubclassDelegate: class {
func buttonTapped(cell: CellSubclass)
}
class CellSubclass: UITableViewCell {
@IBOutlet var someButton: UIButton!
weak var delegate: CellSubclassDelegate?
override func prepareForReuse() {
super.prepareForReuse()
self.delegate = nil
}
@IBAction func someButtonTapped(sender: UIButton) {
self.delegate?.buttonTapped(self)
}
ViewController.swift
class MyViewController: UIViewController, CellSubclassDelegate {
@IBOutlet var tableview: UITableView!
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! CellSubclass
cell.delegate = self
// Other cell setup
}
// MARK: CellSubclassDelegate
func buttonTapped(cell: CellSubclass) {
guard let indexPath = self.tableView.indexPathForCell(cell) else {
// Note, this shouldn't happen - how did the user tap on a button that wasn't on screen?
return
}
// Do whatever you need to do with the indexPath
print("Button tapped on row \(indexPath.row)")
}
}
Upvotes: 70
Reputation: 2551
UPDATE: Getting the indexPath of the cell containing the button (both section and row):
Using Button Position
Inside of your buttonTapped
method, you can grab the button's position, convert it to a coordinate in the tableView, then get the indexPath of the row at that coordinate.
func buttonTapped(_ sender:AnyObject) {
let buttonPosition:CGPoint = sender.convert(CGPoint.zero, to:self.tableView)
let indexPath = self.tableView.indexPathForRow(at: buttonPosition)
}
NOTE: Sometimes you can run into an edge case when using the function view.convert(CGPointZero, to:self.tableView)
results in finding nil
for a row at a point, even though there is a tableView cell there. To fix this, try passing a real coordinate that is slightly offset from the origin, such as:
let buttonPosition:CGPoint = sender.convert(CGPoint.init(x: 5.0, y: 5.0), to:self.tableView)
Previous Answer: Using Tag Property (only returns row)
Rather than climbing into the superview trees to grab a pointer to the cell that holds the UIButton, there is a safer, more repeatable technique utilizing the button.tag property mentioned by Antonio above, described in this answer, and shown below:
In cellForRowAtIndexPath:
you set the tag property:
button.tag = indexPath.row
button.addTarget(self, action: "buttonClicked:", forControlEvents: UIControlEvents.TouchUpInside)
Then, in the buttonClicked:
function, you reference that tag to grab the row of the indexPath where the button is located:
func buttonClicked(sender:UIButton) {
let buttonRow = sender.tag
}
I prefer this method since I've found that swinging in the superview trees can be a risky way to design an app. Also, for objective-C I've used this technique in the past and have been happy with the result.
Upvotes: 61
Reputation: 361
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
}
}
Upvotes: 7
Reputation: 6159
giorashc almost had it with his answer, but he overlooked the fact that cell's have an extra contentView
layer. Thus, we have to go one layer deeper:
guard let cell = sender.superview?.superview as? YourCellClassHere else {
return // or fatalError() or whatever
}
let indexPath = itemTable.indexPath(for: cell)
This is because within the view hierarchy a tableView has cells as subviews which subsequently have their own 'content views' this is why you must get the superview of this content view to get the cell itself. As a result of this, if your button is contained in a subview rather than directly into the cell's content view, you'll have to go however many layers deeper to access it.
The above is one such approach, but not necessarily the best approach. Whilst it is functional, it assumes details about a UITableViewCell
that Apple have never necessarily documented, such as it's view hierarchy. This could be changed in the future, and the above code may well behave unpredictably as a result.
As a result of the above, for longevity and reliability reasons, I recommend adopting another approach. There are many alternatives listed in this thread, and I encourage you to read down, but my personal favourite is as follows:
Hold a property of a closure on your cell class, have the button's action method invoke this.
class MyCell: UITableViewCell {
var button: UIButton!
var buttonAction: ((Any) -> Void)?
@objc func buttonPressed(sender: Any) {
self.buttonAction?(sender)
}
}
Then, when you create your cell in cellForRowAtIndexPath
, you can assign a value to your closure.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! MyCell
cell.buttonAction = { sender in
// Do whatever you want from your button here.
}
// OR
cell.buttonAction = buttonPressed(closure: buttonAction, indexPath: indexPath) // <- Method on the view controller to handle button presses.
}
By moving your handler code here, you can take advantage of the already present indexPath
argument. This is a much safer approach that the one listed above as it doesn't rely on undocumented traits.
Upvotes: 177
Reputation: 432
Try using #selector to call the IBaction.In the cellforrowatindexpath
cell.editButton.tag = indexPath.row
cell.editButton.addTarget(self, action: #selector(editButtonPressed), for: .touchUpInside)
This way you can access the indexpath inside the method editButtonPressed
func editButtonPressed(_ sender: UIButton) {
print(sender.tag)//this value will be same as indexpath.row
}
Upvotes: 1
Reputation: 2239
Sometimes button may be inside of another view of UITableViewCell. In that case superview.superview may not give the cell object and hence the indexPath will be nil.
In that case we should keep finding the superview until we get the cell object.
Function to get cell object by superview
func getCellForView(view:UIView) -> UITableViewCell?
{
var superView = view.superview
while superView != nil
{
if superView is UITableViewCell
{
return superView as? UITableViewCell
}
else
{
superView = superView?.superview
}
}
return nil
}
Now we can get indexPath on button tap as below
@IBAction func tapButton(_ sender: UIButton)
{
let cell = getCellForView(view: sender)
let indexPath = myTabelView.indexPath(for: cell)
}
Upvotes: 0
Reputation: 67
In Swift 3. Also used guard statements, avoiding a long chain of braces.
func buttonTapped(sender: UIButton) {
guard let cellInAction = sender.superview as? UITableViewCell else { return }
guard let indexPath = tableView?.indexPath(for: cellInAction) else { return }
print(indexPath)
}
Upvotes: 0
Reputation: 6159
After seeing Paulw11's suggestion of using a delegate callback, I wanted to elaborate on it slightly/put forward another, similar suggestion. Should you not want to use the delegate pattern you can utilise closures in swift as follows:
Your cell class:
class Cell: UITableViewCell {
@IBOutlet var button: UIButton!
var buttonAction: ((sender: AnyObject) -> Void)?
@IBAction func buttonPressed(sender: AnyObject) {
self.buttonAction?(sender)
}
}
Your cellForRowAtIndexPath
method:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! Cell
cell.buttonAction = { (sender) in
// Do whatever you want from your button here.
}
// OR
cell.buttonAction = buttonPressed // <- Method on the view controller to handle button presses.
}
Upvotes: 2
Reputation: 508
For Swift2.1
I found a way to do it, hopefully, it'll help.
let point = tableView.convertPoint(CGPoint.zero, fromView: sender)
guard let indexPath = tableView.indexPathForRowAtPoint(point) else {
fatalError("can't find point in tableView")
}
Upvotes: 9
Reputation: 8782
I used convertPoint method to get point from tableview and pass this point to indexPathForRowAtPoint method to get indexPath
@IBAction func newsButtonAction(sender: UIButton) {
let buttonPosition = sender.convertPoint(CGPointZero, toView: self.newsTableView)
let indexPath = self.newsTableView.indexPathForRowAtPoint(buttonPosition)
if indexPath != nil {
if indexPath?.row == 1{
self.performSegueWithIdentifier("alertViewController", sender: self);
}
}
}
Upvotes: 1
Reputation: 72750
Since the sender of the event handler is the button itself, I'd use the button's tag
property to store the index, initialized in cellForRowAtIndexPath
.
But with a little more work I'd do in a completely different way. If you are using a custom cell, this is how I would approach the problem:
cellForRowAtIndexPath
Upvotes: 3