如何從父視圖控制器檢測容器視圖中的焦點UITextField

Question

我有一個帶有多個文本框的容器視圖。 我在父視圖控制器（自定義鍵盤）中也有一個按鈕。 我想做的是先選擇文本框，然后在我點擊按鈕時希望將一些值填充到最后一個選定的/重點突出的文本框中。 我怎樣才能做到這一點？ 也歡迎任何其他方式。 （我在原始代碼中有多個容器視圖，並嘗試對所有視圖使用一個鍵盤）

class MainViewController: UIViewController {
    var weightVC : WeightViewController!
    var focusedElement : UITextField

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if (segue.identifier == "weight") {
            weightVC = segue.destination as? WeightViewController
        }
    }

    @IBAction func button1Clicked(_ sender: Any) {

        if weightVC != nil {
            weightVC.sampleTextBox1.text = "1"
            //I want this sampleTextBox1 to be dynamic like weightVC.focusedInput = "1"
        }

    }
}

extension MainViewController:ChildToParentProtocol {
   func setFocusedElement(with value: UITextField){
      focusedElement = value
   }
}

容器視圖控制器

protocol ChildToParentProtocol: class {
    func setFocusedElement(with value:UITextField)
}

class WeightViewController: UIViewController {

    weak var delegate:  ChildToParentProtocol? = nil

    @IBOutlet weak var sampleTextBox1: UITextField!
    @IBOutlet weak var sampleTextBox2: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    // sampleTextBox1 Editing Did Begin event
    @IBAction func editBeginSampleText1(_ sender: Any) {
        print("edit begin")
        delegate?.setFocusedElement(with: sampleTextBox1)
    }

}

換句話說，我只是想在輕按按鈕時保留對上一個重點突出的UITextFild的引用。 希望我的要求足夠明確。 如果有辦法實現，請指導我。

謝謝

Answer 1

如果我正確理解了您的問題，則可以通過使用其標記來跟蹤哪個UITextField被點擊。 您可以使用UITextFieldDelegate來獲取所選的UITextField標簽。

考慮下面的WeightViewController代碼

protocol ChildToParentProtocol: class {
    //Changed value to Int for passing the tag.
    func setFocusedElement(with value: Int)
}

import UIKit

class WeightViewController: UIViewController {

    @IBOutlet weak var tf1: UITextField!
    @IBOutlet weak var tf2: UITextField!

    var selectedTFTag = 0
    weak var delegate: ChildToParentProtocol? = nil

    override func viewDidLoad() {
        super.viewDidLoad()

        //Assign delegate and tags to your TF
        tf1.delegate = self
        tf2.delegate = self

        tf1.tag = 1
        tf2.tag = 2
    }
}

extension WeightViewController: UITextFieldDelegate {
    func textFieldDidBeginEditing(_ textField: UITextField) {
        //Get the selected TF tag
        selectedTFTag = textField.tag
        //Pass tag to parent view
        delegate?.setFocusedElement(with: selectedTFTag)
    }
}

現在，在父視圖ViewController您需要進行一些修改。 我在進行更改以實現您的要求的地方添加了評論。

import UIKit

//You need to confirm your ChildToParentProtocol with your UIViewController
class ViewController: UIViewController, ChildToParentProtocol {

    var selectedTFTag = 0
    var weightVC : WeightViewController!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "weight" {
            weightVC = segue.destination as? WeightViewController
            //You need to pass delegate to containerview to make it working.
            weightVC.delegate = self
        }
    }

    @IBAction func btn1Tapped(_ sender: Any) {

        //According to selected Tag perform your action
        if selectedTFTag > 0 {
            switch selectedTFTag {
            case 1:
                //set up first UITextField
                weightVC.tf1.text = "First textfield was selected"
                print("1")
            case 2:
                //set up second UITextField
                weightVC.tf2.text = "Second textfield was selected"
            default:
                break
            }
        }
    }

    @IBAction func btn2Tapped(_ sender: Any) {

        //According to selected Tag perform your action
        if selectedTFTag > 0 {
            switch selectedTFTag {
            case 1:
                //set up first UITextField
                weightVC.tf1.text = "First textfield was selected"
                print("1")
            case 2:
                //set up second UITextField
                weightVC.tf2.text = "Second textfield was selected"
            default:
                break
            }
        }
    }

    func setFocusedElement(with value: Int) {
        //Get selected TF tag with delegate
        selectedTFTag = value
    }
}

您可以檢查此演示項目以獲取更多信息。