SharedViewModel not clearing when poping fragment

user_10870164 0
Viewed 1664

I'm using a shared view model like here

But the problem is that when I clear my last fragment, I want to clear the viewmodel, or kill its instance, but somehow it survives when I leave the last fragment that uses it

How can I programatically clear this viewmodel ?

I use it like this

Fragment A

private val model: SharedViewModel by activityViewModels()

    override fun onViewCreated() {

     model.getTotal().observe(viewLifecycleOwner, Observer { cartTotal ->
                total = cartTotal
            })

    }

From fragment B I sent the total

Fragment B

private val model: SharedViewModel by activityViewModels()

    override fun onViewCreated() {

     model.setTotal = 10
}

But when leaving Fragment A with that data (doing popBackStack since I'm using navigation components) it does not clear the viewmodel, instead when I open again my fragment , the data stills there

I suspect that the viewmodel is tied with my Container Activity and not the lifecycle of the fragments itself, so

How can I remove the instance or clear my viewmdel when I hit my last fragment ?

Thanks

android-architecture-navigation android-viewmodel android-fragments kotlin android
2 Answers

If you want to get a ViewModel associated with a parent fragment, your inner fragment should follow the by viewModels JavaDoc and use:

val viewmodel: MYViewModel by viewmodels ({requireParentFragment()})

This says to use the parent Fragment as the owner of your ViewModel.

(The parent fragment would use by viewModels() as it is accessing its own ViewModels)

user_16763630

you can also clear viewModelStore manually after Fragment A destroyed. something like this :

override fun onDetach() {
    super.onDetach()
    requireActivity().viewModelStore.clear()
}

then your viewModel instance will be cleared. for checking this work you can debug onCleared method of your viewModel.

user_25114350
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