更改ViewControllers时如何保持UISwitch状态？ [英] How do i keep UISwitch state when changing ViewControllers?

问题描述

当我从一个视图控制器移动到另一个视图控制器时，第一个控制器上的开关将自行重置并且不保持其状态。
如何在查看其他控制器后返回时保存状态？如何在关闭应用程序后保存其状态。我已经查看了各种stackOverflow问题和响应以及Apple文档，但似乎没有任何工作。

When I move from one view controller to another, the switch on the first controller resets itself and does not retain its state. How can I make it save its state when come back to it after viewing other controllers? And how do I make it save its state after closing the app. I have looked at the various stackOverflow questions and responses and the apple documentation, but nothing seems to work.

这是我的具有交换机的View Controller的类。 / p>

Here is my class for the View Controller that has the switch.

class Days: UIViewController {
    @IBOutlet weak var switchButton: UISwitch!
    var switchState = true
    let switchKey = "switchState"
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
    @IBAction func saveSwitchPressed(sender:AnyObject) {
        if self.switchButton.on {
            self.switchState = true
            NSUserDefaults.standardUserDefaults().setBool(self.switchState, forKey: switchKey)
            NSUserDefaults.standardUserDefaults().synchronize()
            println(NSUserDefaults.standardUserDefaults().boolForKey(switchKey))
        } else {
            self.switchState = false
            NSUserDefaults.standardUserDefaults().setBool(self.switchState, forKey: switchKey)
            NSUserDefaults.standardUserDefaults().synchronize()
            println(NSUserDefaults.standardUserDefaults().boolForKey(switchKey))
        }
    }
}

我是Swift的初学者，通常是Xcode。提前感谢您的时间和帮助：）

I'm a beginner to Swift and generally Xcode. Thank you in advance for your time and help :)

推荐答案

Xcode 8.3•Swift 3.1

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var switchButton: UISwitch!

    override func viewDidLoad() {
        super.viewDidLoad()
        switchButton.isOn =  UserDefaults.standard.bool(forKey: "switchState")
    }

    @IBAction func saveSwitchPressed(_ sender: UISwitch) {
        UserDefaults.standard.set(sender.isOn, forKey: "switchState")
    }
}

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