Update: I've tried changing setValue to setObject, and the same error occurred.Upon further investigation with breakpoints and the LLDB, they are nil before the controller is even presented. I'm not saving them right.
I'm trying to simply save a couple of strings of text, and display them on another view using Swift. I'm not sure why I'm having such a hard time. Here is how I'm trying to accomplish this:
VC1
#IBAction func registerTapped(sender : AnyObject)
// Save the login information
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setValue(username.text, forKey: "username")
defaults.setValue(password.text, forKey: "password")
if firstName.text.isEmpty == false {
defaults.setValue(firstName.text, forKey: "firstname")
}
if lastName.text.isEmpty == false {
defaults.setValue(lastName.text, forKey: "lastname")
}
let profileView = ProfileViewController()
self.presentViewController(profileView, animated: true, completion: nil)
}
}
Cool. That looks like the correct way to save strings in UITextFields based upon my research. So, I open up VC2 and try to load the saved text into the new UITextField's, like so:
override func viewDidLoad() {
super.viewDidLoad()
let defaults = NSUserDefaults.standardUserDefaults()
username.text = defaults.stringForKey("username")
password.text = defaults.stringForKey("password")
if let first = defaults.stringForKey("firstname")
{
firstName.text = first
}
if let last = defaults.stringForKey("lastname") {
lastName.text = last
}
}
I get the crash fatal error: unexpectedly found nil while unwrapping an Optional value. I've been digging through tutorials for hours and can't for the life of me figure out what I am doing wrong.
Is it because it an an optional? This is my LLDB output:
Your issue has nothing to do NSUserDefaults, whats nil are your labels username, password, etc. in your second controller.
You should add a segue to your button (the one with registerTapped) to show the second controller and remove the last two lines in registerTapped.
Break your code into steps and debug each one. Your code would crash if your outlet is nil or if the key/value pair doesn't exist. Check that both username and password (The text fields) are not nil, as well as that the defaults results aren't nil:
var text: String?
text = defaults.stringForKey("username")
if let text = text
{
if let username = username
{
username.text = text
}
else
{
println("username field is nil!")
}
}
else
{
println("defaults stringForKey("username") = nil!")
}
text = defaults.stringForKey("password")
if let text = text
{
if let password = password
{
password.text = text
}
else
{
println("password field is nil!")
}
}
else
{
println("defaults stringForKey("password") = nil!")
}
Related
For each UITextView using UserDefaults, I've made a function to save and a function to display.
Whatever text is added needs to be displayed at the time of adding, saved and then displayed again when opening the app again.
If I install the app with ONLY the function to save, quit the app and add the function to display then reinstall without deleting the installed app everything works perfectly.
If I install the app with both functions added it doesn't work.
There has to be a simple solution for this, I'm obviously doing something wrong.
The data from one textView is used to calculate results and then to display them on the other textView.
All data is added with other functions, none by the user.
numberHistoryView.isEditable = false
numberHistoryView.isSelectable = false
func saveHistoryTextView()
{
let defaults = UserDefaults.standard
let numberHistory = numberHistoryView.text
defaults.set(numberHistory, forKey: "combos")
}
func displaySavedHistory()
{
let defaults = UserDefaults.standard
let savedCombos = defaults.object(forKey: "combos") as? String ?? ""
numberHistoryView.text = savedCombos
}
func saveFrequencyTextView()
{
let defaults = UserDefaults.standard
let numberFrequency = numberFrequencyCount.text
defaults.set(numberFrequency, forKey: "frequency")
}
func displaySavedFrequency()
{
let defaults = UserDefaults.standard
let savedFrequency = defaults.object(forKey: "frequency") as? String ?? ""
numberFrequencyCount.text = savedFrequency
}
override func viewWillDisappear(_ animated: Bool)
{
saveHistoryTextView()
saveFrequencyTextView()
}
override func viewWillAppear(_ animated: Bool)
{
displaySavedHistory()
displaySavedFrequency()
}
This depends on the order and timing in which you are calling save and display methods.
When you're installing a fresh app, there will be no data in saved in UserDefaults. So when you call displaySavedHistory() and displaySavedFrequency() methods in viewWillAppear(_:), nothing will be fetched because nothing is saved yet.
Now, when you save the data using saveHistoryTextView() and saveFrequencyTextView() methods in viewWillDisappear(_:) and then you kill and run the app again, the saved data will be fetched and displayed.
Also, since you're saving the data in UserDefaults, and UserDefaults are saved within the sandbox, so the data won't persist when you delete the app. You've to save the data in iCloud or keychain etc. if you want to persist the data even after app deletion.
Once I put my brain into a theta state with the right frequency I managed to figure it out.
Thanks to #Naresh and all other contributors for trying to help as you may have assisted me a little.
The solution basically just required a simple if statement.
Everything now works perfectly.
func saveHistoryTextView()
{
if numberHistoryView.text?.count != nil
{
let defaults = UserDefaults.standard
defaults.set(numberHistoryView.text!, forKey: "combos")
}
}
func displaySavedHistory()
{
let defaults = UserDefaults.standard
if let savedCombos = defaults.string(forKey: "combos")
{
numberHistoryView.text = savedCombos
}
}
func saveFrequencyTextView()
{
if numberFrequencyCount.text?.count != nil
{
let defaults = UserDefaults.standard
defaults.set(numberFrequencyCount.text!, forKey: "frequency")
}
}
func displaySavedFrequency()
{
let defaults = UserDefaults.standard
if let savedFrequency = defaults.string(forKey: "frequency")
{
numberFrequencyCount.text = savedFrequency
}
}
}
override func viewWillDisappear(_ animated: Bool)
{
saveHistoryTextView()
saveFrequencyTextView()
}
override func viewWillAppear(_ animated: Bool)
{
displaySavedHistory()
displaySavedFrequency()
}
You can do it with property observer as:
private let DATA_KEY = "Saved Data"
//After initialising the outlet we can set the data
#IBOutlet weak var textView: UITextView! {
didSet {
textView.text = self.data
}
}
private var data: String {
set {
//Save data in user defaults
UserDefaults.standard.set("The value you will assign", forKey: DATA_KEY)
}
get {
//get the data from user defaults.
return UserDefaults.standard.value(forKey: DATA_KEY) as? String ?? ""
}
}
//UITextViewDelegate: set the text data on end of UITextView editing
func textViewDidEndEditing(_ textView: UITextView) {
self.data = textView.text
}
I'm building an app that uses firebase for authentication and database functionality. Once a user signs up, a database record is stored for that user, containing some basic information like first name, last name etc.
Once a user logs in with his credentials I want to set a global variable (perhaps userDefaults?) which contains the user data for that specific user. Otherwise I have to fetch user data for every time I want to fill a label with for instance, a user's first name.
I managed to set userdefaults upon login and use this info in UIlables. But when I let users make changes to their data, of which some is important for the functioning of the app, I can update the server AND the userdefaults but the app itself doesn't update with the correct data. It keeps the old data in (for example) UIlables.
I would love to get some more insight on what the best work-flow is to manage situations like these.
When opening the app, i have a tabBarController set as rootviewcontroller. In the load of tabbarcontroller I have the following code retrieving the user data from firebase and saving it to userdefaults:
guard let uid = Auth.auth().currentUser?.uid else { return }
Database.database().reference().child("users").child(uid).observeSingleEvent(of: .value, with: { (snapshot) in
print(snapshot.value ?? "")
guard let dictionary = snapshot.value as? [String: Any] else { return }
let firstname = dictionary["First name"] as? String
let lastname = dictionary["Last name"] as? String
print("first name is: " + firstname!)
UserDefaults.standard.set(firstname, forKey: "userFirstName")
print(UserDefaults.standard.value(forKey: "userFirstName"))
self.setupViewControllers()
}
Then I continue on loading in all the viewcontrollers in the tabBarController:
self.setupViewControllers()
During that process the labels in those viewcontrollers get filled in with the userdefaults data.
This is an example of a label being filled in with userDefaults but not being updated upon changing of userdefaults:
let welcomeLabel: UILabel = {
let label = UILabel()
let attributedText = NSMutableAttributedString(string: "Welcome ")
attributedText.append(NSAttributedString(string: "\(UserDefaults.standard.string(forKey: "userFirstName")!)"))
label.attributedText = attributedText
label.font = UIFont.systemFont(ofSize: 30, weight: .bold)
return label
}()
this is a function i'm using to update the first name (via a textfield filled in by the user):
#objc func updateName() {
guard let uid = Auth.auth().currentUser?.uid else { return }
Database.database().reference().child("users").child(uid).updateChildValues(["First name" : updateNameField.text ?? ""])
UserDefaults.standard.set(updateNameField.text, forKey: "userFirstName")
print(UserDefaults.standard.value(forKey: "userFirstName"))
}
So you'll have to organize things first. In a new file define constants such as below. These constant will be accessible in global scope unless private
Constants.swift
private let storedusername = "usname"
private let storedName = "uname"
private let displaypic = "udp"
private let aboutme = "udesc"
var myusername : String {
get {
return (UserDefaults.standard.string(forKey: storedusername)!)
} set {
UserDefaults.standard.set(newValue, forKey: storedusername)
}
}
var myname : String {
get {
return (UserDefaults.standard.string(forKey: storedName)!)
} set {
UserDefaults.standard.set(newValue, forKey: storedName)
}
}
var myProfileImage : Data {
get {
return (UserDefaults.standard.data(forKey: displaypic)!)
} set {
UserDefaults.standard.set(newValue, forKey: displaypic)
}
}
var myAboutMe : String? {
get {
return (UserDefaults.standard.string(forKey: aboutme)!)
} set {
UserDefaults.standard.set(newValue, forKey: aboutme)
}
}
Now the next time you want to save anything in UserDefaults, you'll just do the following anywhere throughout your code base :
myusername = "#CVEIjk"
And to retrive it, just call it :
print(myusername)
IMPORTANT NOTE --
Always remember to initialize them. You can do this as the user signs up. As soon as they fill out their details and hit submit, just save them to these variables. That wouldn't cause unnecessary crash.
You'll have to save them at every location you perform updates regarding these nodes in the database.
Now, the refreshing views part. I am taking a scenario where your ProfileView.swift has the view and user goes to EditProfile.swift for updating the content.
You initialize all your observers the place where the update will have the immediate effect. Because the view immediately after the update matters. The rest will be called through the getter of the aboutme
ProfileView.swift
func openEditView() {
NotificationCenter.default.addObserver(self, selector: #selector(fetchUserDetails), name: Notification.Name("update"), object: nil)
//setting this right before the segue will create an observer specifically and exclusively for updates. Hence you don't have to worry about the extra observers.
perform(segue: With Identifier:)// Goes to the editProfile page
}
This function will be initially called in viewDidLoad(). At this time you need to make sure you have all the data, else it will produce no values. But if you are storing everything as the user signs up, you are safe.
#objc func fetchUserDetails() {
if uid != nil {
if myname.count > 0 { // This will check if the variable has anything in the memory or not. Dont confuse this with [Array].count
self.nameLabel = myname
}
}
}
This function also acts an ab observer method. So when the notifications are posted they can run again.
Now, EditProfile.swift
In the block where you are updating the server, save the values and then create a Notification.post and put this method right before you dismiss(toViewController:)
func updateUserCacheData(name: String, username: String, aboutme: String, ProfilePhoto: UIImage? = nil) {
DispatchQueue.global().async {
myname = name
myusername = username
myAboutMe = aboutme
if self.newImage != nil {
myProfileImage = self.newImage!.jpegData(compressionQuality: 1)!
}
DispatchQueue.main.async {
NotificationCenter.default.post(name: .refreshProfileViews, object: nil)
}
}
}
func updateToServerAndBackToProfileView() {
self.updateUserCacheData(name: iname!, username: iusername, aboutme: iaboutme!)
self.dismiss(animated: true, completion: nil)
}
}
As long as this goes back to ProfileView, your views will be instantly refreshed. You can keep an observer wherever you view will be first displayed after the dismiss. the rest will fetch updated content always. Also, don't forget to deinit your Observer in ProfileView
//This code is in ProfileView.swift
deinit {
NotificationCenter.default.removeObserver(self, name: Notification.Name("update"), object: nil)
}
Also, in cases where the content might be empty, simply initialize it with empty content. For example, if user doesn't choose to add aboutme while signing up, you can just put
`myaboutme = ""`
This will create a safe environment for you and you are well set.
I am trying to load a value that has been inputted by the user in the viewDidLoad via a String. I am using UserDefaults to save the users value that they input into a UITextField (userValue), I then save this to the String 'search'. I am able to print out the value of search in the GoButton function, and it works fine, but when I load my ViewController as new, the value of 'search' is equal to nil. The aim here is to have the users previous search saved, and loaded into the UITextField (that is used as a search box) upon loading the ViewController.
Code Below:
class ViewController: UIViewController {
#IBOutlet weak var userValue: UITextField!
var search: String!
}
viewDidLoad:
override func viewDidLoad() {
if (search != nil)
{
userValue.text! = String (search)
}
}
Button Function:
#IBAction func GoButton(_ sender: Any) {
let userSearch: String = userValue.text!
let perference = UserDefaults.standard
perference.set(userSearch, forKey: "hello")
perference.value(forKey: "hello")
let value = perference.value(forKey: "hello") as! String
search = value
print (search) // <<this works, it prints out the users search value
}
#VishalSharma has the right idea, but the code should probably look more like…
override func viewDidLoad() {
super.viewDidLoad()
if let search = UserDefaults.standard.string(forKey: "hello") {
userValue.text = search
}
}
or even more simply…
userValue.text = UserDefaults.standard.string(forKey: "hello")
When you load, search is effectively nil.
So either you read userDefaults in viewDidload or you come through a segue: then you can load search in the prepare.
I've always found it convenient and useful to store all UserDefault properties as an extension within the same file along with their getters and setters. It is far easier to maintain, use and read. by using the #function keyword for the key you are referencing the variable's name and not a string that can be accidentally changed somewhere else in code.
UserDefaults.swift
import Foundation
// An Extension to consolidate and manage user defaults.
extension UserDefaults {
/// A value Indicating if the user has finished account setup.
/// - Returns: Bool
var finishedAcountSetup: Bool {
get { return bool(forKey: #function) }
set { set(newValue, forKey: #function) }
}
/// The hello text at the start of the application.
/// - Returns: String?
var helloText: String? {
get { return string(forKey: #function) }
set {set(newValue, forKey: #function) }
}
//etc...
}
When you use these values reference the standard settings:
//Setting
UserDefaults.standard.helloText = "Updated Hello Text"
// Getting
// for non-optional value you can just get:
let didCompleteSetup = UserDefaults.standard.finishedAcountSetup
// Otherwise, safely unwrap the value with `if-let-else` so you can set a default value.
if let text = UserDefaults.standard.helloText {
// Ensure there is text to set, otherwise use the default
label.text = text
} else {
// helloText is nil, set the default
label.text = "Some Default Value"
}
obviously, it provides nil because when view controller load the search is nil try this.
let perference = UserDefaults.standard
override func viewDidLoad() {
super.viewDidLoad()
if (perference.value(forKey: "hello") != nil) {
search = perference.value(forKey: "hello") as! String
userValue.text! = String (search)
}
}
I am passing a User object into another segue. For whatever reason I can print out the object and view all the information in the console. I can even unwrap the data but when I go to insert the data into an outlet it crashes.
var user : User? {
didSet {
if let name = user?.name {
print(name)
nameLabel.text = name
}
}
}
As you can see the property exists, however as soon as I try to apply it to my IBOutlet it crashes....
If you are setting the value from some other controller and ChatVC is not loaded then your nameLabel is nil, you can prevent crash by checking nil for it.
var user : User? {
didSet {
if let name = user?.name {
print(name)
if nameLabel != nil {
nameLabel.text = name
}
}
}
}
Also if your setting the nameLabel where you have created instance of ChatVC then instead of doing this you need to set Label text in viewDidLoad of ChatVC like this.
override func viewDidLoad() {
super.viewDidLoad()
nameLabel.text = user?.name
}
I am learning Xcode and creating a very simply program with a textbox(txt box) in which the user enters a value, a button (btnCalc) that performs a calculation, and a label (lblcalcdnumber) that shows the calc'd number. I have already selected Number Pad to be displayed as the dropdown keyboard but i want to check to make sure that if they enter anything other than a number that nothing happens. The code i have works but i feel like there should be a cleaner solution. Essential i want them to only enter Integers in the textbook.
// Mark: Actions
#IBAction func btnCalc(sender: UIButton) {
// let txtbox text beome int
let number1 = Int(txtBox.text!)
// let possibleInt convert mystring to int to check for nil, txtbox becomes OPTIONAL
let possibleInt = Int(txtBox.text!)
let number = 25
if possibleInt != nil {
let combinednumber = "\(Int(number1!) * number)"
lblCalcedNumber.text = combinednumber
}
else {
txtBox.text = ""
txtBox.placeholder = "Please Enter a Valid Number"
}
}
You can use if and let together to create an optional. If the value is not nil it will cast to possibleInt, otherwise, it will evaluate as false.
#IBAction func btnCalc(sender: UIButton) {
if let possibleInt = Int(txtBox.text!) {
let combinednumber = "\(possibleInt * 25)"
lblCalcedNumber.text = combinednumber
}
else {
txtBox.text = ""
txtBox.placeholder = "Please Enter a Valid Number"
}
}
Your variables 'number1' and 'possibleInt' have the same value, so you only need one of them for this section of code. Since 'number' is only used once it would be better to use the value itself rather than create a variable for it, however, if you use it elsewhere keep it as a variable so you only need to change your code in one spot. If you weren't using the possibleInt/number1 value inside the if statement, you could be even more efficient by doing if Int(txtBox.text!) != nil. Try this:
// Mark: Actions
#IBAction func btnCalc(sender: UIButton) {
let possibleInt = Int(txtBox.text!)
if possibleInt != nil {
let combinednumber = "\(possibleInt * 25)"
lblCalcedNumber.text = combinednumber
}
else {
txtBox.text = ""
txtBox.placeholder = "Please Enter a Valid Number"
}
}