ios - 委托(delegate)函数未被调用 iOS Swift

Question

在这里，我试图通过使用协议(protocol)将值从一个类 LanguageSelectionTVC 传递到另一个 RegistrationVC。

当我尝试在 LanguageSelectionTVC 中调用方法 self.delegate?.setSelectedLangauges(self.languagesSpokenArray) 时，它不会调用方法 setSelectedLangauges 类内 Registration VC 有人可以建议我哪里出错了吗？

protocol LanguageSelectionTVCProtocol {
    func setSelectedLangauges(_ valueSent: [String])
}


class LanguageSelectionTVC: UITableViewController {
    var delegate                    : LanguageSelectionTVCProtocol? = nil

   func saveAndClose() {
        self.delegate?.setSelectedLangauges(self.languagesSpokenArray)
        dismiss()
   }

}


class RegistrationVC:           UIViewController,
                                UITableViewDelegate,
                                UITableViewDataSource,
                                LanguageSelectionTVCProtocol{

    func setSelectedLangauges(_ valueSent: [String]){  
         self.showLanguagesSpoken(valueSent)
    }
}

从 RegistrationVC 移动到 LanguageSelectionTVC。下面的 tableView 方法在我的 RegistrationVC

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let row     = indexPath.row
        let section = indexPath.section

        let currentCell = tableView.cellForRow(at: indexPath) as! UITableViewCell
        if section == 4 && row == 0 {
            // The user has clicked on languages spoken cell
            self.performSegue(withIdentifier: "LanguageSelectionTVC", sender: self)
        }
    }

Answer 1

您需要从 preparForSegue 访问 LanguageSelectionTVC 以设置它的 delegate。因此，覆盖 RegistrationVC 中的prepare(for:sender:)。

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "LanguageSelectionTVC" { 
        let vc = segue.destination as! LanguageSelectionTVC
        vc.delegate = self
    }
}