Downloading firebase data in the app delegate - ios

Question

I have begun building an app that lets a user sign up and create a family. Right now I am downloading the data for the user from the log in screen and, from the appDelegate if the user is already logged in. However, when the user data is downloaded from the appDelegate I get nil values.
Whats weird is that I have the following written in each of my three view controllers(controlled by a tab controller):
var user: User? {
didSet {
print(user!.name!)
}
}
When the data eventually downloads from the appDelegate the correct name is printed. However, trying to use the user variable at any other time gives nil.
Also, when the data is downloaded from the log in screen it works perfectly. Very confused about this and would hugely appreciate any help. Thanks in advance.

Answer 1

I figured out what was wrong. Nothing to do with firebase.
While in the app delegate after downloading the user data, I tried to set the properties of the viewControllers in my tabViewController. What I actually did was create a new instance of each view controller, set its properties(which is why the didSet property observer fired) but then when setting the rootViewController I created a new instance of the tabController which I think then created new instances of the three viewControllers.
This is what the old code was in the appDelegate:
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
FIRApp.configure()
let storyBoard = UIStoryboard(name: "Main", bundle: nil)
if let user = FIRAuth.auth()?.currentUser {
downloadUserData(user)
self.window?.rootViewController = storyBoard.instantiateViewControllerWithIdentifier("Home")
} else {
window?.rootViewController = storyBoard.instantiateViewControllerWithIdentifier("SignIn")
}
return true
}
func downloadUserData(user: FIRUser) {
let ref = FIRDatabase.database().reference()
ref.child("users").queryOrderedByKey().queryEqualToValue(user.uid).observeSingleEventOfType(.Value, withBlock: { (snapshot) in
for child in snapshot.children {
if let name = child.value!["name"] as? String, let familyID = child.value!["signedInTo"] as? String {
self.user = User(uid: user.uid, name: name)
ref.child("families").queryOrderedByKey().queryEqualToValue(familyID).observeSingleEventOfType(.Value, withBlock: { (snapshot) in
for child in snapshot.children {
if let name = child.value!["name"] as? String {
self.family = Family(uid: familyID, name: name)
let storyBoard = UIStoryboard(name: "Main", bundle: nil)
let tabVC = storyBoard.instantiateViewControllerWithIdentifier("Home") as? TabBarViewController
tabVC?.user = self.user
tabVC?.family = self.family
let choresNav = tabVC?.viewControllers![0] as? UINavigationController
let choresVC = choresNav?.topViewController as? ChoresViewController
choresVC?.user = self.user
choresVC?.family = self.family
}
}
})
}
}
})
}
This is the appDelegate now, along with a custom TabBarViewController:
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
FIRApp.configure()
let storyBoard = UIStoryboard(name: "Main", bundle: nil)
if let user = FIRAuth.auth()?.currentUser {
downloadUserData(user)
} else {
window?.rootViewController = storyBoard.instantiateViewControllerWithIdentifier("SignIn")
}
return true
}
func downloadUserData(user: FIRUser) {
let ref = FIRDatabase.database().reference()
ref.child("users").queryOrderedByKey().queryEqualToValue(user.uid).observeSingleEventOfType(.Value, withBlock: { (snapshot) in
for child in snapshot.children {
if let name = child.value!["name"] as? String, let familyID = child.value!["signedInTo"] as? String {
self.user = User(uid: user.uid, name: name)
ref.child("families").queryOrderedByKey().queryEqualToValue(familyID).observeSingleEventOfType(.Value, withBlock: { (snapshot) in
for child in snapshot.children {
if let name = child.value!["name"] as? String {
self.family = Family(uid: familyID, name: name)
let storyBoard = UIStoryboard(name: "Main", bundle: nil)
let tabVC = storyBoard.instantiateViewControllerWithIdentifier("Home") as? TabBarViewController
tabVC?.user = self.user
tabVC?.family = self.family
self.window?.rootViewController = tabVC
}
}
})
}
}
})
}
TabBarController:
var user: User?
var family: Family?
override func viewDidLoad() {
super.viewDidLoad()
print(user?.name)
print(family?.name)
let navVC = self.viewControllers![0] as? UINavigationController
let itemsNav = self.viewControllers![1] as? UINavigationController
let leaderNav = self.viewControllers![2] as? UINavigationController
let choresVC = navVC!.topViewController as? ChoresViewController
let itemsVC = itemsNav!.topViewController as? ShoppingListViewController
let leaderVC = leaderNav!.topViewController as? LeaderBoardViewController
choresVC?.user = self.user
choresVC?.family = self.family
itemsVC!.user = self.user
itemsVC!.family = self.family
leaderVC!.user = self.user
leaderVC!.family = self.family
}
The code I have still isn't great but it has solved the problem. Hope it helps some of you out.