I'm learning application development working on a quiz game. I'd like to add statistics to the game. For example, the average score since the app has been downloaded. How can I store the scores on the device in order to reuse them after the app has been closed?
You should take a look at UserDefault. It's basically a dictionary that persists until the user uninstalls your app. I like to write a wrapper around it to get strong typing and ease of reference:
struct Preferences {
static func registerDefaults() {
UserDefaults.standard.register(defaults: [kAverageScore: 0])
}
// Define your key as a constant so you don't have to repeat a string literal everywhere
private static let kAverageScore = "averageScore"
static var averageScore: Double {
get { return UserDefaults.standard.double(forKey: kAverageScore) }
set { UserDefaults.standard.set(newValue, forKey: kAverageScore) }
}
}
Here's how to use it: before you call it for the first time in your app, you must register the defaults. These are the values that your app ships with. On iOS, it only really matters for the very first time the user launches your app. On OS X, do this every time your app starts because the user can delete the app's preferences from ~/Library/Application Support.
// You usually do this in viewDidLoad
Preferences.registerDefaults()
From then on, getting and setting the property is easy:
let averageScore = Preferences.averageScore
Preferences.averageScore = 5.5
You should take a look at UserDefaults
Example
let defaults = UserDefaults.standard
defaults.set(25, forKey: "Age")
defaults.set(true, forKey: "UseTouchID")
defaults.set(Double.pi, forKey: "Pi")
To read values back
let age = defaults.integer(forKey: "Age")
let useTouchID = defaults.bool(forKey: "UseTouchID")
let pi = defaults.double(forKey: "Pi")
UserDefaults
Related
At my project i need to send user id's to widget in iOS. But for do that, my user needs to open application once. Without opening, information stays only 1 day, after that it vanishes and widget stops showing information and await for opening application.
For do that i used appGroup.
What is the correct way to use transfer data from my project to widget?
Swift 5
Follow these steps to pass data from the host app to extensions.
Select project target > Capabilities > add new app group (if you have enabled permissions for your developer account otherwise enable that first)
Select the extension target and repeat the same.
if let userDefaults = UserDefaults(suiteName: "group.com.yourAppgroup") {
createEventDic.removeAll()
let eventDic = NSMutableDictionary()
eventDic.setValue("YourString", forKey: "timeFontName")
createEventDic.append(eventDic)
let resultDic = try? NSKeyedArchiver.archivedData(withRootObject: createEventDic, requiringSecureCoding: false)
userDefaults.set(resultDic, forKey: "setWidget")
userDefaults.synchronize()
} else {
}
Now go to your app extension and do these steps to get the passed data.
if let userDefaults = UserDefaults(suiteName: "group.com.yourAppGroup") {
guard let testcreateEvent = userDefaults.object(forKey: "testcreateEvent") as? NSData else {
print("Data not found in UserDefaults")
return
}
do {
guard let eventsDicArray = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(testcreateEvent as Data) as? [NSMutableDictionary] else {
fatalError("loadWidgetDataArray - Can't get Array")
}
for eventDic in eventsDicArray {
let timeFontName = eventDic.object(forKey: "timeFontName") as? String ?? ""
}
} catch {
fatalError("loadWidgetDataArray - Can't encode data: \(error)")
}
}
Hopefully, it will help. Cheers!
For do that i used appGroup.
What is the correct way to use transfer data from my project to
widget?
What you did so far (App Grouping) is one of the steps that you should follow. Next, as mentioned in App Extension Programming Guide - Sharing Data with Your Containing App:
After you enable app groups, an app extension and its containing app
can both use the NSUserDefaults API to share access to user
preferences. To enable this sharing, use the initWithSuiteName: method
to instantiate a new NSUserDefaults object, passing in the identifier
of the shared group.
So, what you have to do so far is to let the data to be transferred by the UserDefautls. For instance:
if let userDefaults = UserDefaults(suiteName: "group.com.example.myapp") {
userDefaults.set(true, forKey: "myFlag")
}
thus you could pass it to the widget:
if let userDefaults = UserDefaults(suiteName: "group.com.example.myapp") {
let myFlag = userDefaults.bool(forKey: "myFlag")
}
And you follow the same approach for passing the data vise-versa (from the widget to the project).
In Xamarin Forms, we need to use DI to pass the data to the ios project then we can put it into NSUserDefaults
Info: Grouping application is mandatory
Xamarin iOS project - Putting Data into NSUserDefaults
var plist = new NSUserDefaults("group.com.test.poc", NSUserDefaultsType.SuiteName);
plist.SetBool(true, "isEnabled");
plist.Synchronize();
Today Extension - Getting data from NSUserDefaults
var plist = new NSUserDefaults("group.com.test.poc", NSUserDefaultsType.SuiteName);
var result = plist.BoolForKey("isEnabled");
Console.WriteLine($"The result of NSUserdefaults: logesh {result}");
I've developed a game and I released it to the App Store about 2 months ago (Supernatural Slayer). The game uses user defaults to store player data such as level, xp, gold, etc.
I want to update the game to include review requests which I programmed based on help from hacking with swift. (I also had to switch ad networks since chart boost suspended my account indefinitely for no reason...)
My question is that I seem to remember during development about 4-6 months ago that every time I added another variable to save and load from user defaults it would cause an existing game to crash and I would have to start from scratch by deleting and reloading the game onto my phone to erase user defaults. But now that I'm adding the reviewRequest variable it isn't causing the same error, I'm not sure if I'm not testing correctly and if once I update all of my players will lose their progress...
My code for the save and load functions is below, will this cause an error for existing users that update my app if I add the reviewRequest variable and the save and load lines for it? I've updated both my Mac OS and Xcode since it used to crash for me, so maybe this is why it is not an issue anymore?
let defaults = UserDefaults.standard
var reviewRequest = 0
func save() {
defaults.set(reviewRequest, forKey: "Review Request")
defaults.set(player.name, forKey: "PlayerName")
}
func load() {
player.name = defaults.object(forKey: "PlayerName") as! String
reviewRequest = defaults.integer(forKey: "Review Request")
}
You should try adding a nil check to avoid trying to retrieve an empty key.
func load() {
if defaults.object(forKey: "PlayerName") != nil {
player.name = defaults.object(forKey: "PlayerName") as! String
} else {
//Default name or something similar
}
if defaults.object(forKey: "ReviewRequest") != nil {
reviewRequest = defaults.integer(forKey: "Review Request")
} else {
reviewRequest = 0
}
}
Here's my problem: I have several variables in my viewController, for example:
var money = 0.0
I want to store this value on the device as soon as the app is going to terminate. To do this, I need to be able to acces the variable in the appDelegate and use it in 'applicationWillTerminate'. I then want it to be stored on the device and when the app restarts I want to be able to acces the stored value again. How do I do this in (swift) Xcode 8.2?
"applicationWillTerminate" as Apple docs say, is no more called in modern app unless You set a specific flag in plist.
The correct approach is to store values in NSUserDefault:
For swift 3.0:
1) let's create a class to manage money, and saving them:
class MoneyManager: NSObject {
private let MONEY_KEY = "money"
static let sharedInstance = MoneyManager()
var money: Float? {
get {
let returnValue = UserDefaults.standard.object(forKey: MONEY_KEY) as? Float
return returnValue
}
set(newValue){
if newValue == nil {
UserDefaults.standard.removeObject(forKey: MONEY_KEY)
} else {
UserDefaults.standard.set(newValue!, forKey: MONEY_KEY)
}
UserDefaults.standard.synchronize()
}
}
}
2) to use it in every controller you need:
let money = MoneyManager.sharedInstance.money
if money == nil{
MoneyManager.sharedInstance.money = 1000
}
As every time we call UserDefaults.standard.synchronize(), we are safe everything is saved.
I have an iOS app with a share extension. I am trying to share data between them using NSUserDefaults and App Groups but, while I can write into the NSUD object, read it, and synchronize() without error, reading in the extension always results in nil.
I have an app group, the literal string "group.net.foo.bar" for which both the app & extension have configured under Capabilities -> App Groups. This string is in a constants struct in my app:
struct Forum {
static let APP_GROUP = "group.net.foo.bar"
static let AUTH_KEY = "AUTH_KEY"
}
In the main app I create a UserDefaults object and write to it:
fileprivate lazy var userDefaults: UserDefaults = {
let defaults = UserDefaults()
defaults.addSuite(named: Forum.APP_GROUP)
return defaults
}()
// later
userDefaults.set(apiKey, forKey: Forum.AUTH_KEY)
userDefaults.synchronize()
Creating a new NSUD object after that synchronize() and retrieving the AUTH_KEY works. In the extension, I create an NSUD and try to retrieve the value, to no avail:
private lazy var userDefaults: UserDefaults = {
let defaults = UserDefaults()
defaults.addSuite(named: Forum.APP_GROUP)
return defaults
}()
// later
private func getApiKey() -> String? {
return userDefaults.string(forKey: Forum.AUTH_KEY)
}
// returns nil
In all of my reading of the Apple docs and depressingly-similar questions here on Stack Overflow I can't divine what I've done incorrectly.
Xcode Version 8.0 (8A218a), also tested with Xcode 8.1 Beta 2. Same behavior on simulator andy my iPhone 6s running iOS 10.
Not sure if defaults.addSuite(named: ...) does the same as UserDefaults(suiteName: ...). In my app I use appGroups this way and it works as expected:
// write
if let userDefaults = UserDefaults(suiteName: appGroupName) {
userDefaults.set("---" as AnyObject, forKey: "distance")
userDefaults.set("---" as AnyObject, forKey: "altitude")
...
userDefaults.synchronize()
}
// read
if let userDefaults = UserDefaults(suiteName: appGroupName) {
self.distanceLabel.text = userDefaults.string(forKey: "distance")
self.altitudeLabel.text = userDefaults.string(forKey: "altitude")
}
if you suffer this problem when you try to save data to extension APP by using userDefault,maybe you had written this code : [[NSUserDefaults standardUserDefaults] initWithSuiteName:#"group.xxx.com"];,this code reset default userDefault. Actually,the correct code is : [[NSUserDefaults alloc] initWithSuiteName:#"group.xxx.com"]; enter link description here
I'm working on an app and a widget that the widget needs to get data from app. I've used the following codes to read and write on NSUserDefaults. And also I used $(PRODUCT_BUNDLE_IDENTIFIER).widget for widget and $(PRODUCT_BUNDLE_IDENTIFIER) referring to this post. But widget cannot get the data from app or NSUserDefaults. How can I make it work?
func addTask(name: String?) {
let key = "keyString"
tasks.append(name!)
let defaults = NSUserDefaults(suiteName: "group.Mins")
defaults?.setObject(tasks, forKey: key)
defaults?.synchronize()
}
///////
let defaults = NSUserDefaults(suiteName: "group.Mins")
let key = "keyString"
if let testArray : AnyObject = defaults?.objectForKey(key) {
let readArray : [String] = testArray as! [String]
timeTable = readArray
timeTable = timeTable.sort(<)
print("GOT IT")
print("timetable: \(timeTable)")
}
To read and save from the same set of NSUserDefaults you need to the the following:
In your main app, select your project in the project navigator.
Select your main app target and choose the capabilities tab.
Switch on App Groups (this will communicate with the developer portal, as it is generating a set of entitlements, and relevant App Id and so forth).
Create a new container. According to the help, it must start with “group.”, so give it a name like “group.myapp.test”.
Select your Today Extension target and repeat this process of switching on app groups. Don’t create a new one, rather select this newly created group to signify that the Today Extension is a member of the group.
Write to your NSUserDefaults:
// In this example I´m setting FirstLaunch value to true
NSUserDefaults(suiteName: "group.myapp.test")!.setBool(true, forKey: "FirstLaunch")
Read from NSUserDefaults:
// Getting the value from FirstLaunch
let firstLaunch = NSUserDefaults(suiteName: "group.myapp.test")!.boolForKey("FirstLaunch")
if !firstLaunch {
...
}
Swift 4.x:
Write:
UserDefaults(suiteName: "group.myapp.test")!.set(true, forKey: "FirstLaunch")
Read:
UserDefaults(suiteName: "group.myapp.test")!.bool(forKey: "FirstLaunch")