如何存储我的第一个文本字段以免第二次快速查询

Question

Thanks in advanced for the help.

I created a UITextField that when the user write a link and enter after that my textfield disappear and my webView Appear.

What i am trying to do is, when the user write the first time their link, the textfield save that link and when the user open again the App, the web view open directly from the last link what user wrote textfield. basically the stored link should run the second time.

Here is all my code,

    import UIKit
import Foundation


let urlKey = "User URL"

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var webView: UIWebView!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.webView.hidden = true
            self.textField.addTarget(self, action: #selector(ViewController.textFieldDidUpdate(_:)), forControlEvents: UIControlEvents.EditingChanged)

      if doesURLExist() {
        self.textField.text = getURL()



  }


}
    // Text Field Delegate
    func textFieldDidUpdate(textField: UITextField)
    {
        // Remove Spaces
        textField.text = textField.text!.stringByReplacingOccurrencesOfString(" ", withString: "", options: [], range: nil)



        // Validate URL
        NSURL.validateUrl(textField.text, completion: { (success, urlString, error) -> Void in
            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                if (success)
                {

                  self.saveURL(urlString!)
                  self.webView.hidden = false
                  self.textField.hidden = true 
                  let request = NSURLRequest(URL: NSURL(string: urlString!)!)
                  self.webView.loadRequest(request)

                }
                else
                {
                    self.webView.stopLoading()
                    self.webView.hidden = true
                }


            })

        })



          }
    @IBAction func dismissKeyboard(sender: AnyObject) {
        self.resignFirstResponder()
        self.view.endEditing(true)
    }
  func saveURL(urlString: String)  {
    let defaults = NSUserDefaults.standardUserDefaults()
    defaults.setObject(urlString, forKey: urlKey)
  }

  func getURL() -> String {
    let defaults = NSUserDefaults.standardUserDefaults()
    let urlString = defaults.objectForKey(urlKey) as! String
    return urlString
  }

  func doesURLExist() -> Bool {
    let defaults = NSUserDefaults.standardUserDefaults()
    guard let _ = defaults.objectForKey(urlKey) where defaults.objectForKey(urlKey) is String else {
      return false
    }
    return true
  }


}

here is my project in github: enter link description here

Answer 1

You should save the entered string to user defaults. When your app opens you should check user defaults to see if there's already a saved string.

Swift 2 code to save your URL to user defaults:

NSUserDefaults.standardUserDefaults().setObject(urlString!, forKey: "EnteredURLString")

Swift 2 code to check whether there's a saved URL string:

if let urlString = NSUserDefaults.standardUserDefaults().stringForKey("EnteredURLString") {
}

Answer 2

You'll want to check if the url exists first by calling doesURLExist , if it does, you opt out of presenting that textfield. If it does not exist, call saveURL . NSUserDefaults provides a simple means to store lightweight data.

let urlKey = "User URL"     

func saveURL(urlString: String)  {
    let defaults = NSUserDefaults.standardUserDefaults()
    defaults.setObject(urlString, forKey: urlKey)
}

func getURL() -> String {
    let defaults = NSUserDefaults.standardUserDefaults()
    let urlString = defaults.objectForKey(urlKey) as! String
    return urlString
}

func doesURLExist() -> Bool {
    let defaults = NSUserDefaults.standardUserDefaults()
    guard let _ = defaults.objectForKey(urlKey) where defaults.objectForKey(urlKey) is String else {
        return false
    }
    return true
}

So your class should look something like:

import UIKit
import Foundation

let urlKey = "User URL"     

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet weak var textField: UITextField!
    @IBOutlet weak var webView: UIWebView!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.webView.hidden = true

        self.textField.addTarget(self, action: #selector(ViewController.textFieldDidUpdate(_:)), forControlEvents: UIControlEvents.EditingChanged)

        if(doesURLExist) {
            self.textField.text = getURL()
        }
        // Demo UI Settings
    }
}

  // Text Field Delegate
func textFieldDidUpdate(textField: UITextField)
{
    // Remove Spaces
    textField.text = textField.text!.stringByReplacingOccurrencesOfString(" ", withString: "", options: [], range: nil)

    // Validate URL
    NSURL.validateUrl(textField.text, completion: { (success, urlString, error) -> Void in
        dispatch_async(dispatch_get_main_queue(), { () -> Void in
            if (success) {
              self.saveURL(urlString)
              self.webView.hidden = false
              self.textField.hidden = true 
              let request = NSURLRequest(URL: NSURL(string: urlString!)!)
              self.webView.loadRequest(request)
            } else {
                self.webView.stopLoading()
                self.webView.hidden = true
            }
        })
    })
}

Don't forget to add the original functions to your class.