检测在 tableview 中按下的 uibutton：Swift 最佳实践

Question

I have a tableview with a variable number of cells representing students that correspond to their particular instructor. They are custom cells with a button that triggers a segue to a new VC, bringing up detailed information on the student whose cell it was. My question is:

What is the best practice in swift for identifying which button was pressed?

Once i know the index path, I can identify which student's information needs to be passed to the next VC. There is a great answer for objective C in the post below, but I'm not sure how to translate to Swift. Any help would be much appreciated.

Detecting which UIButton was pressed in a UITableView

Answer 1

If your code allows, I'd recommend you set the UIButton tag equal to the indexPath.row , so when its action is triggered, you can pull the tag and thus row out of the button data during the triggered method. For example, in cellForRowAtIndexPath you can set the tag:

button.tag = indexPath.row
button.addTarget(self, action: "buttonClicked:", forControlEvents: UIControlEvents.TouchUpInside)

then in buttonClicked: , you can fetch the tag and thus the row:

func buttonClicked(sender:UIButton) {

    let buttonRow = sender.tag
}

Otherwise, if that isn't conducive to your code for some reason, the Swift translation of this Objective-C answer you linked to :

- (void)checkButtonTapped:(id)sender
{
    CGPoint buttonPosition = [sender convertPoint:CGPointZero toView:self.tableView];
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:buttonPosition];
    if (indexPath != nil)
    {
     ...
    }
}

is:

func checkButtonTapped(sender:AnyObject) {
      let buttonPosition = sender.convert(CGPoint.zero, to: self.tableView)
    let indexPath = self.tableView.indexPathForRow(at: buttonPosition)
    if indexPath != nil {
        ...
    }
}

Answer 2

Swift 3.0 Solution

cell.btnRequest.tag = indexPath.row

    cell.btnRequest.addTarget(self,action:#selector(buttonClicked(sender:)), for: .touchUpInside)

    func buttonClicked(sender:UIButton) {

            let buttonRow = sender.tag
        }

Answer 3

Updated for Swift 3

If the only thing you want to do is trigger a segue on a touch, it would be against best practice to do so via a UIButton. You can simply use UIKit's built in handler for selecting a cell, ie func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) . You could implement it doing something like the following:

Create a custom UITableViewCell

class StudentCell: UITableViewCell {
    // Declare properties you need for a student in a custom cell.
    var student: SuperSpecialStudentObject!

    // Other code here...
}

When you load your UITableView, pass the data into the cell from you data model:

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "StudentCell", for: indexPath) as! StudentCell
    cell.student = superSpecialDataSource[indexPath.row]
    return cell
}

Then use didSelectRow atIndexPath to detect when a cell has been selected, access the cell and it's data, and pass the value in as a parameter to performSegue .

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let cell = tableView.cellForRow(at: indexPath) as! StudentCell

    if let dataToSend = cell.student {
        performSegue(withIdentifier: "DestinationView", sender: dataToSend)
    }
}

And finally in prepareForSegue :

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "DestinationView" {
        let destination = segue.destination as! DestinationViewController
        if let dataToSend = sender as? SuperSpecialStudentObject {
            destination.student = dataToSend
        }
    }
}

Alternatively if you want them to only select a part of the cell instead of when they touch anywhere inside the cell, you could add an accessory item onto your cell such as the detail accessory item (looks like the circle with an "i" inside of it) and use override func tableView(_ tableView: UITableView, accessoryButtonTappedForRowWith indexPath: IndexPath) instead.

Answer 4

Another possible solution would be using dispatch_block_t . If you do it with Storyboard you first have to create a member variable in your custom UITableViewCell class.

var tapBlock: dispatch_block_t?

Then you have to create an IBAction and call the tapBlock .

@IBAction func didTouchButton(sender: AnyObject) {
    if let tapBlock = self.tapBlock {
        tapBlock()
    }
}

In your view controller with the UITableView you can simply react to the button events like this

let cell = tableView.dequeueReusableCellWithIdentifier("YourCellIdentifier", forIndexPath: indexPath) as! YourCustomTableViewCell

cell.tapBlock = {
   println("Button tapped")
}

However you have to be aware when accessing self inside the block, to not create a retain cycle. Be sure to access it as [weak self] .

Answer 5

Swift 3

@ cellForRowAt indexPath

cell.Btn.addTarget(self, action: #selector(self.BtnAction(_:)), for: .touchUpInside)

Then

func BtnAction(_ sender: Any)
    {

        let btn = sender as? UIButton

    }

Answer 6

It's never a good idea to use tags to identify cells and indexPaths, eventually you'll end up with a wrong indexPath and consequently the wrong cell and information.

I suggest you try the code bellow (Working with UICollectionView, didn't tested it with a TableView, but it probably will work just fine):

SWIFT 4

@objc func buttonClicked(_ sender: UIButton) {
    if let tableView = tableViewNameObj {
        let point = tableView.convert(sender.center, from: sender.superview!)

        if let wantedIndexPath = tableView.indexPathForItem(at: point) {
            let cell = tableView.cellForItem(at: wantedIndexPath) as! SpecificTableViewCell

        }
    }
}

Answer 7

Detecting the Section and row for UiTableView indexPath on click Button click

//MARK:- Buttom Action Method
    @objc func checkUncheckList(_sender:UIButton)
    {
        if self.arrayRequestList != nil
        {

          let strSection = sender.title(for: .disabled)

          let dict = self.arrayRequestList![Int(strSection!)!]["record"][sender.tag]

          print("dict:\(dict)")

          self.requestAcceptORReject(dict: dict, strAcceptorReject: "1")
        }

    }

Here is UITableView Cell Method to add the targate

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "OtherPropertySelectiingCell", for: indexPath as IndexPath) as! OtherPropertySelectiingCell
        cell.btnAccept.tag = indexPath.row
        cell.btnAccept.setTitle("\(indexPath.section)", for: .disabled)
        cell.btnAccept.addTarget(self, action: #selector(checkUncheckList(_sender:)), for: .touchUpInside)
        return cell
    }

Answer 8

Swift 5. In cellForRowAtIndexPath you set the tag:

cell.shareButton.tag = indexPath.row
cell.shareButton.addTarget(self, action: #selector(shareBtnPressed(_:)), for: .touchUpInside)

Then in shareBtnPressed you fetch the tag

  @IBAction func shareBtnPressed(_ sender: UIButton) {

    let buttonRow = sender.tag

    print("Video Shared in row \(buttonRow)")
}

Answer 9

As a follow up to @Lyndsey and @longbow's comments, I noticed that when I had the segue in storyboard going from the button to the destinationVC, the prepareForSegue was being called before the buttonClicked function could update the urlPath variable. To resolve this, I set the segue directly from the first VC to the destinationVC, and had the segue performed programmatically after the code in buttonClicked was executed. Maybe not ideal, but seems to be working.

func buttonClicked(sender:UIButton) {
    let studentDic = tableData[sender.tag] as NSDictionary
    let studentIDforTherapyInt = studentDic["ID"] as Int
    studentIDforTherapy = String(studentIDforTherapyInt)
    urlPath = "BaseURL..."+studentIDforTherapy
    self.performSegueWithIdentifier("selectTherapySegue", sender: sender)
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if (segue.identifier == "selectTherapySegue") {
        let svc = segue.destinationViewController as SelectTherapyViewController;
        svc.urlPath = urlPath
    }

Answer 10

Updated for Swift 5:

Place the following code within your ViewController class

@IBAction func buttonClicked(_ sender: UIButton) {
    if let tableView = tableView {
        let point = tableView.convert(sender.center, from: sender.superview!)

//can call wantedIndexPath.row here

        }
    }
}

Answer 11

I am doing it via prepareforSegue

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

            let indexPath = self.tableView.indexPathForSelectedRow()
            let item = tableViewCollection[indexPath!.row].id
            let controller = segue.destinationViewController as? DetailVC

            controller?.thisItem = item
    }

and on the next controller i will just reload the full item properties, by knowing its id and setting it to the var thisItem in the DetailVC

Answer 12

I was going to use the indexPath approach until I came to understand that it would be unreliable/wrong in some situations (deleted or moved cell, for instance).

What I did is simpler. By example, I am displaying a series of colors and their RGB values—one per tableview cell. Each color is defined in an array of color structures. For clarity these are:

struct ColorStruct {
    var colorname:String    = ""
    var red:   Int = 0
    var green: Int = 0
    var blue:  Int = 0
}

var colors:[ColorStruct] = []       // The color array

My prototype cell has a var to hold the actual index/key into my array:

class allListsCell: UITableViewCell {
    @IBOutlet var cellColorView: UIView!
    @IBOutlet var cellColorname: UILabel!
    var colorIndex = Int()  // ---> points directly back to colors[]

    @IBAction func colorEditButton(_ sender: UIButton, forEvent event: UIEvent) {
        print("colorEditButton: colors[] index:\(self.colorIndex), \(colors[self.colorIndex].colorname)")
    }
}

This solution takes three lines of code, one in the prototype cell definition , the second in the logic that populates a new cell, and the the third in the IBAction function which is called when any cell's button is pressed. Because I have effectively hidden the "key" (index) to the data in each cell AS I am populating that new cell, there is no calculation required -and- if you move cells there is no need to update anything.

Answer 13

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

1. 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 = ""

}

2. create your cell class

class InviteCell: UITableViewCell {

@IBOutlet var imgProfileImage: UIImageView!
@IBOutlet var btnCheck: UIButton!
@IBOutlet var lblName: UILabel!
@IBOutlet var lblEmail: UILabel!
}

3. 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()

}

 }