How to change a tab bar item from the tab bar controller - ios

Question

I got tab bar controller with three view controllers setup. One of those view controllers changes its tab bar item badgeValue when I open it. I would like to change this badgeValue already when I arrive at the first tab.
I created a Tabbarcontoller: UITabBarController class but don't know how to easily access the items of the sub views. Here is the code from my Tabbarcontoller class:
class TabBarController: UITabBarController, MainMethodsDelegate {
var myFriendsRequests: [UserInfo] = []
var friendRequestsCount: Int = 0
func getFriendsRequests_Methods_Destination(myFriendsRequest: UserInfo) {
myFriendsRequests.append(myFriendsRequest)
self.friendRequestsCount = myFriendsRequests.count
DispatchQueue.main.async {
//friendsBarItem.badgeValue = String(self.friendRequestsCount)
}
}
let mainMethods = MainMethods()
override func viewDidLoad() {
super.viewDidLoad()
mainMethods.delegate = self
mainMethods.getFriendsRequests()
}
}
And here the working code from the sub view controller:
class FriendsViewController: UIViewController, MainMethodsDelegate {
var myFriendsRequests: [UserInfo] = []
var friendRequestsCount: Int = 0
func getFriendsRequests_Methods_Destination(myFriendsRequest: UserInfo) {
myFriendsRequests.append(myFriendsRequest)
self.friendRequestsCount = myFriendsRequests.count
DispatchQueue.main.async {
self.friendsBarItem.badgeValue = String(self.friendRequestsCount)
}
}
let mainMethods = MainMethods()
override func viewDidLoad() {
super.viewDidLoad()
mainMethods.delegate = self
mainMethods.getFriendsRequests()
}
#IBOutlet weak var friendsBarItem: UITabBarItem!
}
I'm looking for a simple way to access the sub view controllers or at least the bar items where it says:
//friendsBarItem.badgeValue = String(self.friendRequestsCount)
I'm not sure if delegates is the right way to go?

Answer 1

I would leave the bar item out of the friends controller. It does not need to know about the tabBar. If I were you, I would create a protocol to let know your tabBarController that the number of friend requests has changed.
First, define the protocol:
protocol FriendsRequestDelegate {
func friendsRequestsDidChange(number: Int)
}
Then, add the variable to your FriendsViewController:
weak var delegate: FriendsRequestDelegate?
And, we need to trigger that func, still in FriendsViewController, after fetching the number of friends request, add;
delegate?.friendsRequestsDidChange(number: myFriendsRequests.count)
Finally, make your TabBarController conform to this protocol;
extension TabBarController: FriendsRequestDelegate {
func friendsRequestsDidChange(number: Int) {
friendsBarItem.badgeValue = String(number)
}
}
See what I mean? This way your friendsRequestController doesn't know about the tabBar and it'll keep your code clean.

Answer 2

I've found a quite simple way to access the barItems. I only had to access the array of tabBar items with:
tabBar.items![2].badgeValue = ""
Here is my code for the UITabBarController:
class TabBarController: UITabBarController, MainMethodsDelegate {
var myFriendsRequests: [UserInfo] = []
var friendRequestsCount: Int = 0
func getFriendsRequests_Methods_Destination(myFriendsRequest: UserInfo) {
myFriendsRequests.append(myFriendsRequest)
self.friendRequestsCount = myFriendsRequests.count
DispatchQueue.main.async {
self.tabBar.items![2].badgeValue = String(self.friendRequestsCount)
}
}
let mainMethods = MainMethods()
override func viewDidLoad() {
super.viewDidLoad()
mainMethods.delegate = self
mainMethods.getFriendsRequests()
}
}
The sub view controller does not need to check and update the badgeValue anymore. (This is fine in my case since the getFriendsRequests_Methods_Destination(myFriendsRequest: UserInfo) method gets triggered as soon as there is a new friends request anyways using a (Firestore) snapshot listener.)
My initial way was to access the tabItem from each of the sub view controllers individually using tabBarController!.tabBar.items![2].badgeValue = "" But this would have been redundant in my case.