void NavigationPopCallback(MessageBus bus, NavigationPopInfo navigationPopInfo)
{
if (navigationPopInfo == null)
{
throw new ArgumentNullException(nameof(navigationPopInfo));
}
if (!navigationPopInfo.Force && _isBusy)
{
return;
}
if (_app == null)
{
throw new FieldAccessException(@"Application property not set. Use Init() before navigation");
}
if (_navigations.Count == 0)
{
throw new FieldAccessException(@"Navigation is null. Add NavigationPage first");
}
Device.BeginInvokeOnMainThread(async() => {
_isBusy = true;
try {
await Pop(navigationPopInfo);
}
catch (Exception) {
// ignore
}
_isBusy = false;
});
}
async Task Pop(NavigationPopInfo popInfo)
{
INavigation navigation;
switch (popInfo.Mode)
{
case NavigationMode.Normal:
if (_navigations.TryPeek(out navigation))
{
await NormalPop(popInfo.WithAnimation, navigation);
}
break;
case NavigationMode.Modal:
if (_navigations.TryPop(out navigation) && navigation.ModalStack.Count > 0)
{
await ModalPop(popInfo.WithAnimation, navigation);
}
break;
case NavigationMode.Root:
if (_navigations.TryPeek(out navigation))
{
var pagesToDispose = navigation.NavigationStack?.Count > 0
? navigation.NavigationStack.Where(p => p != navigation.NavigationStack[0]).ToArray()
: null;
await navigation.PopToRootAsync(popInfo.WithAnimation);
DisposePages(pagesToDispose);
}
break;
case NavigationMode.Custom:
await HandleCustomPopNavigation(popInfo);
break;
default:
throw new NotImplementedException();
}
}
Task HandleCustomPopNavigation(NavigationPopInfo popInfo)
{
// TODO: Implement your own navigation stack manipulation using popInfo
return(Task.FromResult(0));
}