ios - swift/用户界面开关 : how to implement a delegate/listener

Question

在我的 UITableViewController 中，我有一个自定义单元格，其中包含一个切换器，如下所示:

import Foundation
import UIKit

class SwitchCell: UITableViewCell {
  @IBOutlet weak var label : UILabel!
  @IBOutlet weak var switchEmail : UISwitch!

  func setEditable(canEdit:Bool) {
      if (canEdit) {
        self.switchEmail.enabled = true
        self.label.highlighted = false
      }
      else {
          self.switchEmail.enabled = false
          self.label.highlighted = true
      }
  }

  func configureCellWithSwitch(labelText:String, switchValue:Bool, enabled:Bool) {

    var labelFrame:CGRect = self.label.frame
    labelFrame.size.height = Settings.labelHeight
    self.label.frame = labelFrame

    self.label.text = labelText

    if (switchValue) {
        self.switchEmail.setOn(true, animated: true)
    }
    else {
        self.switchEmail.setOn(false, animated: true)
    }

    self.setEditable(enabled)

  }
}

我想知道如何实现切换器的监听器/委托(delegate)，以便从 UITableViewController 获取其值。我能够使用实现方法的 UITextField 和 UITextView 为单元格编写委托(delegate)/监听器

func controller(controller: UITableViewCell, textViewDidEndEditing: String, atIndex: Int)

和

func controller(controller: UITableViewCell, textFieldDidEndEditingWithText: String, atIndex: Int)

但我不知道应该如何实现切换器。

Answer 1

UISwitch 没有委托(delegate)协议(protocol)。您可以通过以下方式收听状态:

目标:

// somewhere in your setup:
[self.mySwitch addTarget:self action:@selector(switchChanged:) forControlEvents:UIControlEventValueChanged];


- (void)switchChanged:(UISwitch *)sender {
   // Do something
   BOOL value = sender.on;
}

swift :

mySwitch.addTarget(self, action: "switchChanged:", forControlEvents: UIControlEvents.ValueChanged)

func switchChanged(mySwitch: UISwitch) {
   let value = mySwitch.on
   // Do something
}

swift 3:

mySwitch.addTarget(self, action: #selector(switchChanged), for: UIControlEvents.valueChanged)

func switchChanged(mySwitch: UISwitch) {
    let value = mySwitch.isOn
    // Do something
}

swift 4:

mySwitch.addTarget(self, action: #selector(switchChanged), for: UIControl.Event.valueChanged)

@objc func switchChanged(mySwitch: UISwitch) {
    let value = mySwitch.isOn
    // Do something
}