在 swift 中从 UIPickerView 的选定行设置 UIButton 的标题

Question

我正在尝试从 uipickerview 的选定行设置我的按钮标题。但是，我似乎找不到有效的解决方案。

我已将变量设置为全局变量，因此我可以访问所选变量。但是我似乎无法准确指出用户何时单击退出按钮并能够更新我的按钮标题。

我尝试过的事情：

全局函数（无法工作，因为您无法指定要更改名称的按钮）
Dispatchqueue.main.async - 没有更新我的标题。这里的想法是让它不断检查字符串变化。

我在这里找到的解决方案在 Obj-C 中。我尝试将其转换为 swift https://objectivec2swift.com/#/converter/code/ 但没有成功。 Set Title of UIButton from Selected Row of UIPickerView

@IBAction func CountryPickButton(_ sender: UIButton) {

        Global.setPickerDataSource(data:["Test","test2","test3"])
        Global.setPickerCompletionHandler(int:0)
        let popOverVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "PickerViewPopUpId") as! PickerViewController
        //CountryPickButtonDetector = sender as? UIButton
        self.addChild(popOverVC)
        popOverVC.view.frame = self.view.frame
        self.view.addSubview(popOverVC.view)
        popOverVC.didMove(toParent: self)
        popOverVC.callback { value in
        //CountryPickButton.title.text = value
        sender.setTitle(value, for: UIControl.State)
    }
    }

import UIKit
var test = ""

class PickerViewController: UIViewController {
    @IBOutlet weak var PickerView: UIPickerView!
    var callback : ((String) -> Void)?
    override func viewDidLoad() {
        super.viewDidLoad()
        //self.view.backgroundColor = UIColor.black.withAlphaComponent(0.8)
        PickerView.dataSource = self
        PickerView.delegate = self
        // Do any additional setup after loading the view.
    }
    @IBAction func ExitButton(_ sender: Any) {
        switch Global.pickerCompletionHandler {

        case 0:
            callback?(Global.pickerResult ?? "")
            Global.setProfileCountry(string:
                Global.pickerResult ?? "")
        default:
            print("nothing")

        }
        self.view.removeFromSuperview()
    }

}

extension PickerViewController: UIPickerViewDelegate, UIPickerViewDataSource {
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1 // can be more than 1 component like time/date/year
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return Global.pickerDataSource?.count ?? 1
    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        //Global.pickerResult = Global.pickerDataSource?[row]
        Global.setPickerResult(result: Global.pickerDataSource?[row] ?? "Test" )
    }

    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return Global.pickerDataSource?[row]
    }


}

全局变量

import Foundation

struct Global {
    static var pickerDataSource:[String]? = nil
    static var pickerResult:String? = nil
    static var pickerCompletionHandler:Int? = 0
    static var profileCountry:String? = nil

    static func setPickerDataSource(data:[String]) {
        Global.pickerDataSource = data
    }
    static func setPickerResult(result:String) {
        Global.pickerResult = result
    }
    static func setPickerCompletionHandler(int: Int) {
        Global.pickerCompletionHandler = int
    }
    static func setProfileCountry(string: String)
    {
        Global.profileCountry = string
    }
}

Answer 1

我不知道 Global 是什么东西，最简单的解决方案可能是扩展 pickerCompletionHandler，但这是另一个（简单的）方法：

在 PickerViewController 中添加一个传递 String 值且没有 return 值的回调

var callback : ((String) -> Void)?

并在exitButton中调用它（拜托，请变量和函数名称应该以小写字母开头）

@IBAction func exitButton(_ sender: Any) {
    switch Global.pickerCompletionHandler {

    case 0:
        callback?(Global.pickerResult ?? "")
        Global.setProfileCountry(string:
            Global.pickerResult ?? "")
    default:
        print("nothing")

    }
    self.view.removeFromSuperview()
}

在countryPickButton中（再次：小写字母）设置回调并将sender设置为真实类型。回调设置标题

@IBAction func countryPickButton(_ sender: UIButton) {

    Global.setPickerDataSource(data:["Test","test2","test3"])
    Global.setPickerCompletionHandler(int:0)
    let popOverVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "PickerViewPopUpId") as! PickerViewController
    popOverVC.callback = { value in 
        sender.setTitle(value, for: .normal)
    }
...

在 swift 中从 UIPickerView 的选定行设置 UIButton 的标题

Set Title of UIButton from Selected Row of UIPickerView in swift

swift

uibutton

uipickerview