从保存按钮关闭视图控制器

Question

我在展开/关闭视图控制器时遇到问题。

此视图控制器中的导航栏有两个按钮。左边是一个"展开/退出"按钮，功能正常，关闭当前视图控制器，使用户返回到主设置屏幕。第二个按钮是"保存"按钮，它将用户数据提交到NSUserdefaults。这两个按钮都按照它们的设计进行。虽然我希望"保存"按钮再做一件事。

我希望导航栏"保存"按钮

继续按其设计保存为数据，但我也希望它"展开/退出"该视图控制器并返回主设置视图控制器，就像"展开/退出"导航栏按钮一样。

这是我的视图控制器代码。正如您将能够看到的，我正在从我的"设置保存电子邮件地址"函数中调用"backButtonTapped"函数。我知道正在触发"backButtonTapped"功能，因为"print"命令正在调试窗口中打印。虽然它正在保存我的数据，但它无法关闭视图控制器并展开回主设置视图控制器。

import UIKit
class SettingsViewController: UIViewController {

    @IBOutlet weak var settingEmailAddress: UITextField!
    @IBOutlet weak var settingEmailAddressLastUpdate: UILabel!
    // Constant keys for NSUserDefaults look ups
    static let settingDefaultEmailAddress = "EMAIL_ADDRESS"
    static let settingDefaultEmailAddressLastUpdated = "EMAIL_ADDRESS_LAST_UPDATED"

    //End Setting - Email Address
    @IBAction func settingSaveEmailAddress(sender: AnyObject) {
        if (settingEmailAddress.text!.characters.count > 0) {
            let prefs = NSUserDefaults.standardUserDefaults()
            prefs.setObject(settingEmailAddress.text, forKey: SettingsViewController.settingDefaultEmailAddress)
            saveTimestampEmailAddress()
        }
        dismissKeyboard()
        print(settingEmailAddress.text)
        backButtonTapped(self)


    }
    //End Setting - Email Address

    override func viewDidLoad() {
        super.viewDidLoad()
        // Uncomment these if you want to clear out the saved defaults
        //let appDomain = NSBundle.mainBundle().bundleIdentifier!
        //NSUserDefaults.standardUserDefaults().removePersistentDomainForName(appDomain)
        let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(SettingsViewController.dismissKeyboard))
        view.addGestureRecognizer(tap)
        // update labels from NSUserDefaults
        getUserPreferences()
        // Do any additional setup after loading the view.
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // Updates the view with the user values already stored in NSUserDefaults
    func getUserPreferences() {
        let prefs = NSUserDefaults.standardUserDefaults()
        // Get Email Address
        if let email = prefs.stringForKey(SettingsViewController.settingDefaultEmailAddress) {
            settingEmailAddress.text = email
        }
        // Get the last time something was stored
        let dateFormatter = NSDateFormatter()
        dateFormatter.dateStyle = NSDateFormatterStyle.LongStyle
        dateFormatter.timeStyle = .MediumStyle
        if let lastUpdateStored = (prefs.objectForKey(SettingsViewController.settingDefaultEmailAddressLastUpdated) as? NSDate) {
            settingEmailAddressLastUpdate.text = "Last Update:" + dateFormatter.stringFromDate(lastUpdateStored)
        } else {
            settingEmailAddressLastUpdate.text = "Last Update: Never"
        }
    }

    // MARK: - Keyboard responders so the keyboard goes away when we're done editing.
    // Dismiss the keyboard when the user is finished editing.
    func dismissKeyboard(){
        // Resign the first responder status.
        view.endEditing(true)
    }
    func textFieldShouldReturn(textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }
    // Saves the timestamp of when the user has made a change to the NSUserDefaults
    func saveTimestampEmailAddress() {
        let prefs = NSUserDefaults.standardUserDefaults()
        let timestamp = NSDate()
        prefs.setObject(timestamp, forKey: SettingsViewController.settingDefaultEmailAddressLastUpdated)
        let dateFormatter = NSDateFormatter()
        dateFormatter.dateStyle = NSDateFormatterStyle.LongStyle
        dateFormatter.timeStyle = .MediumStyle
        settingEmailAddressLastUpdate.text = "Last Update:" + dateFormatter.stringFromDate(timestamp)
    }
    func backButtonTapped(sender: AnyObject) {
        self.dismissViewControllerAnimated(true, completion: nil)
            print("Exit Triggered")
    }

}

Answer 1

你可以

写：-

在 Objective-C 中

 [self.navigationController popToRootViewControllerAnimated:YES];

在斯威夫特

 func popToRootViewControllerAnimated(_ animated: Bool) -> [UIViewController]?

在"保存"按钮方法的末尾，如果您的"主设置"视图控制器是根视图控制器。

Answer 2

我创建了这个函数，现在当我按"保存"时，我得到了预期的功能。

1. 保存 NSU ser默认数据

2. 关闭当前视图控制器并返回我的主设置视图控制器"设置主表视图控制器"。

   func closeVCReturnSettings() {
   for controller in self.navigationController!.viewControllers as Array {
       if controller.isKindOfClass(SettingsMainTableViewController) {
           self.navigationController?.popToViewController(controller as UIViewController, animated: true)
           break
       }
       print("Return to settings")
   }
   }