问题
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)
}
回答1:
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.
回答2:
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)")
}
}
回答3:
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.
回答4:
Use an extension to UITableView to fetch the cell for any view:
@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.)
EDIT:
You can download a working demo project that uses the above extension from Github: TableViewExtension.git
回答5:
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")
}
回答6:
Swift 4 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!
回答7:
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
}
}
回答8:
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:
- add an 'indexPath` property to the custom table cell
- initialize it in
cellForRowAtIndexPath - move the tap handler from the view controller to the cell implementation
- use the delegation pattern to notify the view controller about the tap event, passing the index path
回答9:
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.
}
回答10:
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
}
回答11:
I found a very easy and saficiat way to use for manage any cell in tableView and collectionView by using a Model class and this a work as perfectly.
There is indeed a much better way to handle this now. This will work for manage cell and value
here is my output(screenshote) so see this
here is my code
- Its very simple to create model clas, please follow the below procedure. Create swift class with name "RNCheckedModel", write the code as below.
class RNCheckedModel: NSObject {
var is_check = false
var user_name = ""
}
- create your cell class
class InviteCell: UITableViewCell {
@IBOutlet var imgProfileImage: UIImageView!
@IBOutlet var btnCheck: UIButton!
@IBOutlet var lblName: UILabel!
@IBOutlet var lblEmail: UILabel!
}
- and finaly use model class in your UIViewController when you use your UITableView.
class RNInviteVC: UIViewController, UITableViewDelegate, UITableViewDataSource {
@IBOutlet var inviteTableView: UITableView!
@IBOutlet var btnInvite: UIButton!
var checkArray : NSMutableArray = NSMutableArray()
var userName : NSMutableArray = NSMutableArray()
override func viewDidLoad() {
super.viewDidLoad()
btnInvite.layer.borderWidth = 1.5
btnInvite.layer.cornerRadius = btnInvite.frame.height / 2
btnInvite.layer.borderColor = hexColor(hex: "#512DA8").cgColor
var userName1 =["Olivia","Amelia","Emily","Isla","Ava","Lily","Sophia","Ella","Jessica","Mia","Grace","Evie","Sophie","Poppy","Isabella","Charlotte","Freya","Ruby","Daisy","Alice"]
self.userName.removeAllObjects()
for items in userName1 {
print(items)
let model = RNCheckedModel()
model.user_name = items
model.is_check = false
self.userName.add(model)
}
}
@IBAction func btnInviteClick(_ sender: Any) {
}
func tableView(_ tableView: UITableView, numberOfRowsInSection
section: Int) -> Int {
return userName.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell: InviteCell = inviteTableView.dequeueReusableCell(withIdentifier: "InviteCell", for: indexPath) as! InviteCell
let image = UIImage(named: "ic_unchecked")
cell.imgProfileImage.layer.borderWidth = 1.0
cell.imgProfileImage.layer.masksToBounds = false
cell.imgProfileImage.layer.borderColor = UIColor.white.cgColor
cell.imgProfileImage.layer.cornerRadius = cell.imgProfileImage.frame.size.width / 2
cell.imgProfileImage.clipsToBounds = true
let model = self.userName[indexPath.row] as! RNCheckedModel
cell.lblName.text = model.user_name
if (model.is_check) {
cell.btnCheck.setImage(UIImage(named: "ic_checked"), for: UIControlState.normal)
}
else {
cell.btnCheck.setImage(UIImage(named: "ic_unchecked"), for: UIControlState.normal)
}
cell.btnCheck.tag = indexPath.row
cell.btnCheck.addTarget(self, action: #selector(self.btnCheck(_:)), for: .touchUpInside)
cell.btnCheck.isUserInteractionEnabled = true
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 80
}
@objc func btnCheck(_ sender: UIButton) {
let tag = sender.tag
let indexPath = IndexPath(row: tag, section: 0)
let cell: InviteCell = inviteTableView.dequeueReusableCell(withIdentifier: "InviteCell", for: indexPath) as! InviteCell
let model = self.userName[indexPath.row] as! RNCheckedModel
if (model.is_check) {
model.is_check = false
cell.btnCheck.setImage(UIImage(named: "ic_unchecked"), for: UIControlState.normal)
checkArray.remove(model.user_name)
if checkArray.count > 0 {
btnInvite.setTitle("Invite (\(checkArray.count))", for: .normal)
print(checkArray.count)
UIView.performWithoutAnimation {
self.view.layoutIfNeeded()
}
} else {
btnInvite.setTitle("Invite", for: .normal)
UIView.performWithoutAnimation {
self.view.layoutIfNeeded()
}
}
}else {
model.is_check = true
cell.btnCheck.setImage(UIImage(named: "ic_checked"), for: UIControlState.normal)
checkArray.add(model.user_name)
if checkArray.count > 0 {
btnInvite.setTitle("Invite (\(checkArray.count))", for: .normal)
UIView.performWithoutAnimation {
self.view.layoutIfNeeded()
}
} else {
btnInvite.setTitle("Invite", for: .normal)
}
}
self.inviteTableView.reloadData()
}
func hexColor(hex:String) -> UIColor {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.count) != 6) {
return UIColor.gray
}
var rgbValue:UInt32 = 0
Scanner(string: cString).scanHexInt32(&rgbValue)
return UIColor(
red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: CGFloat(1.0)
)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
回答12:
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);
}
}
}
回答13:
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)
}
回答14:
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)
}
来源：https://stackoverflow.com/questions/28659845/swift-how-to-get-the-indexpath-row-when-a-button-in-a-cell-is-tapped