Observable account

So far we are showing the account balances - and the next step is really to sort out the transaction view.

But - before we do that - let's sort out the nested callbacks we currently have.


Callbacks

These work - but - nesting them makes the code harder to follow.

Let's make the account handling use the built in ObservableObject handling - so that when the account changes the view notices this. We can then write a simplified refresh method that will also allow us to refresh the transactions when we add them.


Make Account Service observable

We need to make some changes to the account service.

  • it needs to implement ObservableObject
  • it needs to have a variable that is annotated as @Published
  • the method is no longer static, no longer gets callbacks (and we'll rename it refresh)

Change the class definition to start:

class AccountService : ObservableObject {
    @Published public var account : Account? = nil

Change the method signature to:

public func refresh(token: String, config: Config)

Remove all calls to callback in the method and at the end if we made it that far we set:

self.account = account

Content View

We now want to listen to changes to the service - the view will be notified that a change has happened when the @Published variable changes.

In the content view remove the state variable for account and add

@ObservedObject var accountService = AccountService()

In the view heirarchy - where we have the AccountView - let's use the service variable when present:

if (accountService.account != nil) {
    AccountView(account: accountService.account!)
        .navigationBarTitle(Text(accountService.account!.name), displayMode: .inline)
    }
}

Replace the entire getToken method (which since the last change is badly named too) with a refresh method:

func refresh() {
    if let config = self.config {
        TokenService.getToken(config: config) { (accessToken) in
            if let token = accessToken {
                self.accountService.refresh(token: token, config: config)
                // We will add transaction refresh here later on
            }
        }
    }
}

In the .OK state of askForAuth - call self.refresh()

If you want you can also add another naviagtionBarItem with a suitable icon (Image(systemName: "arrow.clockwise") perhaps) that calls refresh().


Summary

We've updated the app so that the view stack watches for changes to the account. This will make it easier to add the transaction views later on.


GitHub Repository