Accessing and storing viewController variables in appDelegate - ios

Question

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?

Answer 1

"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.