how to popBackStack with popUpTo ?

# compose

[Hasan Nagizade]

how to popBackStack with popUpTo ?

[Filip Wiesner]

Documentation:
https://developer.android.com/jetpack/compose/navigation#nav-to-composable
https://developer.android.com/guide/navigation/navigation-navigate#pop

What specifically do you want to know? This is really a broad question.

[Hasan Nagizade]

thanks for links I already checked them. When I am doing navcontroller.popBackStack to navigate back the viewmodel is kept in the memory. I want to kill that viewmodel

[Filip Wiesner]

What viewmodel? Viewmodel of the screen you pop to or from which you pop?

[Hasan Nagizade]

I will give example. I am in the chat screen and want to go back to chat list screen. Both of them have viewmodels. So when I go back to chat list and open another chat I am getting messages from previous chats. Their viewmodels are still alive. I want to just kill chat screen viewmodel as soon as I go back to chat list

[Hasan Nagizade]

navController.popBackStack doesn't do that

[Filip Wiesner]

I see, so you navigate ChatList -> Chat where you inject your VM using composable function getViewModel(). Then you call navController.popBackStack() which navigates you back to ChatList. When you navigate again to different Chat destination, you get the same VM instance? Can you verify that it is the same instance and not just VM that fetches the same data?

[Hasan Nagizade]

it's not same VM instance. if I open let's say 5 chat it creates 5 viewmodels. so When I open chat 6 I will get every message that was sent in previous 5 chats. I just want to kill the viewmodel as soon as I leave the Chat screen so when I open new chat viewmodel will be freshly created

[Filip Wiesner]

Well if it's different instance, than the previous ViewModel has been killed, no? Than I don't really understand the problem

[Hasan Nagizade]

it's not getting killed. I don't know why. each time it creates different instance and that instance lives in memory

[Filip Wiesner]

Are you sure you don't keep a reference to the Viewmodel somewhere? And can you check that onCleared is called in the VM?

[Hasan Nagizade]

onCleared is not getting called when I navigate back

[Filip Wiesner]

Weird, what dependency injection are you using? Koin?

[Hasan Nagizade]

yes

[Hasan Nagizade]

oh god

[Hasan Nagizade]

I declared it with single

[Hasan Nagizade]

🤦

[Hasan Nagizade]

changed to viewModel but still is not getting cleared

[Filip Wiesner]

There you go 😄 That's weird that you got a different instance actually.

[Hasan Nagizade]

wait emulator is shown offline for some reason let me check again

[Hasan Nagizade]

no luck 😕

[Filip Wiesner]

Well... I don't what else to check 🤷

[Hasan Nagizade]

but somehow it works now 😕

[Hasan Nagizade]

🤔

[Hasan Nagizade]

hahah worked clean build

[Filip Wiesner]

🤦‍♂️

[Hasan Nagizade]

thank you sooo much @Filip Wiesner you saved me tons of headaches

[Filip Wiesner]

No worries 👌
Just next time you have to ask something more specific and it's better to write what you've tried so far. Seeing question like "_how to popBackStack with popUpTo?_" is really annoying because you will have to ask a lot of questions first to find the problem.

[Hasan Nagizade]

Thanks for your patience. I surely will next time 😌