从Swift中的另一个类访问某些值

Question

I have a TableViewCell class like this:

class CampaignsTableViewCell: UITableViewCell {

    @IBOutlet weak var activateButton: UIButton!
    @IBOutlet weak var titleCampaignPlaceholder: UILabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
        setUpButton()
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
        // Configure the view for the selected state
    }

    private func setUpButton(){
        activateButton.backgroundColor = .clear
        activateButton.layer.cornerRadius = 5
        activateButton.layer.borderWidth = 1
        activateButton.layer.borderColor = UIColor.blue.cgColor
    }
}

And, in another class which is a ViewController I have my UITableView methods:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let rowNumber = indexPath.row
    let cellIdentifier = "CampaignTableViewCell"
    guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? CampaignsTableViewCell else {
        fatalError("The dequeued cell is not an instance of TableViewCellController.")
    }

    cell.titleCampaignPlaceholder.text = campaignsArray[rowNumber].campaignName


    return cell
}

I need to use my activateButton in my UITableView method in order to access to campaignsArray. I have another method which requieres values from that array, so I need that method is called every time activateButton is pressed from my UITableView.

Any idea ? Thank you very much

Answer 1

What I like doing in those cases where you have a button inside your UITableViewCell is the following:

Give the cell a closure that is called when tapping on the button like so

class CampaignsTableViewCell: UITableViewCell {
   ... all your code....

   // give your cell a closure that is called when the button is pressed    
   var onButtonPressed: ((_ sender: UIButton) -> ())?

   @IBAction func buttonPressed(sender: UIButton) {  // wire that one up in IB
       onButtonPressed?(sender)
   }
 }

and then inside your TableViewController

let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as! CampaignsTableViewCell

cell.titleCampaignPlaceholder.text = campaignsArray[rowNumber].campaignName

cell.onButtonPressed = { [weak self] sender in
    // Do your magic stuff here
}

return cell

Hope that helps

Answer 2

Your cell will get that event, not tableView . What you need to do is:

Create protocol inside your cell:

protocol CampaignsTableViewProtocol{
    func actionButtonPressed(row: Int)
}

class CampaignsTableViewCell: UITableViewCell {

    @IBOutlet weak var activateButton: UIButton!
    @IBOutlet weak var titleCampaignPlaceholder: UILabel!
    // keep info about row 
    var rowIndex: Int = -1
    // create delegate that will let your tableView about action button in particular row
    var delegate : CampaignsTableViewProtocol?

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
        setUpButton()
        self. activateButton.addTarget(self, action: #selector(self.activatePressed), for: UIControlEvents.touchDown)
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
        // Configure the view for the selected state
    }

    func activatePressed(){
         self.delegate?.actionButtonPressed(row :rowIndex)
    }

    private func setUpButton(){
        activateButton.backgroundColor = .clear
        activateButton.layer.cornerRadius = 5
        activateButton.layer.borderWidth = 1
        activateButton.layer.borderColor = UIColor.blue.cgColor
    }
}

Your tableViewController needs to adopt this protocol:

class MyTableViewController: UITableViewDelegate, UITableViewDataSource, CampaignsTableViewProtocol {
// rest of the code
}

Also, you will need to implement delegate function in your tableViewController:

func actionButtonPressed(row: Int) {
    // get campaign you need
    let campaign = campaignsArray[row]
    // rest of the code
}