swift - TextFields 不会使用展开函数 Swift 中的值进行更新

Question

我有 textfields，一旦从用户选择单元格的 TableViewController 返回，它应该显示一个值。我在 unwind 函数中获得了该值，但 textfields 没有得到更新。当打印值时，它会在展开时正确打印，因此 unwind 应该设置正确，但它不会显示在它的 textfield 中。我还在 TableViewController 中尝试了 prepare(for unwind: 但结果相同。你能看出我做错了什么吗？一如既往地非常感谢。

展开函数:

@IBAction func unwindToDetailsVc(segue: UIStoryboardSegue) {
        //Insert function to be run upon dismiss of VC2
        print("unwindSegue triggered")
        if let vc = segue.source as? CityTableViewController {
            print("segue source is city vc : \(String(describing: vc.city!))")

            self.cityTextField.text = vc.city
        }
        if let vc = segue.source as? RegionTableViewController {
            print("segue source is region vc : \(String(describing: vc.region!))")
            self.regionTextField.text = vc.region
        }
        if let vc = segue.source as? CountryTableViewController {
            print("segue source is country vc : \(String(describing: vc.country!))")
            self.countryTextField.text = vc.country
        }
    }

TableView 中的

didSelect:

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let cell = tableView.cellForRow(at: indexPath) as! CityTableViewCell
        self.city = cell.cityLabel.text ?? ""
        performSegue(withIdentifier: "unwindSegue", sender: self)
//        self.dismiss(animated: true, completion: nil)
    }

准备放松:

override func prepare(for unwind: UIStoryboardSegue, sender: Any?) {
        if unwind.identifier == "unwindSegue"  {
            if let detailsVc = unwind.destination as? ShopDetailsTableViewController {
                detailsVc.cityTextField.text! = city
            }
        }
    }

文本框委托(delegate)函数:

func textFieldDidBeginEditing(_ textField: UITextField) {
        print("Editing textfield")
        if textField.accessibilityIdentifier == "city" {
            print("Editing city textfield")
            performSegue(withIdentifier: "citySegue", sender: self)
        } else if textField.accessibilityIdentifier == "region" {
            print("Editing regio textfield")
            performSegue(withIdentifier: "regionSegue", sender: self)
        } else if textField.accessibilityIdentifier == "country" {
            print("Editing country textfield")
            performSegue(withIdentifier: "countrySegue", sender: self)
        }
    }

Answer 1

你可以简单地使用一个闭包来解决这种问题陈述，

class ViewController: UIViewController {
    @IBOutlet weak var textField: UITextField!

    @IBAction func openTableVC(_ sender: UIButton) {
        if let controller = UIStoryboard.init(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "TableViewController") as? TableViewController {
            controller.handler = {[weak self](city) in
                DispatchQueue.main.async {
                    self?.textField.text = city
                }
            }
            self.navigationController?.pushViewController(controller, animated: true)
        }
    }
}

class TableViewController: UITableViewController {
    var handler: ((String)->())?

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let city = "Delhi"
        self.handler?(city)
        self.navigationController?.popViewController(animated: true)
    }
}

以上代码是通用的，适用于您想要打开 TableViewController 的任何情况。