public override async void ViewAppeared()
{
base.ViewAppeared();
if (_isInitialAppearance)
{
_isInitialAppearance = false;
// Attempt to authenticate silently - with a previously stored token
var hasToken = await AuthService.AcquireTokenSilently();
if (hasToken)
{
// Authenticated, so check for required permissions
await HandleAppPermissions();
}
else
{
// Hasn't authenticated
// Subscribe to the Authentication OnAuthChanged event (fired when authentication succeeds)
AuthService.OnAuthChanged += HandleOnAuthChanged;
// Trigger login screen
OnDisplayLogin?.Invoke();
}
}
}
async void HandleOnAuthChanged(object sender, AuthChangedEventArgs e)
{
if (e.IsLoggedIn)
{
await HandleAppPermissions();
}
else
{
OnDisplayLogin?.Invoke();
}
}
// Called when the Authentication OnAuthChanged event fires - when authentication with credentials succeeds
async void HandleOnAuthChanged(object sender, AuthChangedEventArgs e)
{
if (e.IsLoggedIn)
{
// Authenticated, so check for required permissions
await HandleAppPermissions();
}
else
{
// Not authenticated, so update login screen
OnDisplayLogin?.Invoke();
}
}
public override async void ViewAppeared()
{
base.ViewAppeared();
if (isInitialAppearance)
{
isInitialAppearance = false;
var hasToken = await AuthService.AcquireTokenSilently();
AuthService.OnAuthChanged += HandleOnAuthChanged;
if (hasToken)
{
await HandleAppPermissions();
}
else
{
OnDisplayLogin?.Invoke();
}
}
}