Kotlin: Memory Leak Issues with ViewModel and LiveData in a Fragment Using Navigation Component
I'm prototyping a solution and I'm building a feature where I tried several approaches but none seem to work. I'm working on a personal project and I'm encountering a memory leak issue in my Android application when using ViewModel and LiveData in a Fragment managed by the Navigation Component. After navigating away from the Fragment, the memory profile indicates that the ViewModel is not being cleared properly. I’m using AndroidX libraries version 1.4.0 for Navigation and 2.4.0 for Lifecycle components. I have a Fragment that observes a LiveData object in the ViewModel, and here's the relevant portion of my code: ```kotlin class MyViewModel : ViewModel() { private val _data = MutableLiveData<String>() val data: LiveData<String> get() = _data fun loadData() { // Simulate data loading _data.value = "Hello, World!" } } class MyFragment : Fragment() { private lateinit var viewModel: MyViewModel override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? { viewModel = ViewModelProvider(this).get(MyViewModel::class.java) return inflater.inflate(R.layout.fragment_my, container, false) } override fun onViewCreated(view: View, savedInstanceState: Bundle?) { super.onViewCreated(view, savedInstanceState) viewModel.data.observe(viewLifecycleOwner, { value -> // Update UI }) viewModel.loadData() } } ``` After observing the data, when I navigate away from `MyFragment`, the ViewModel still holds a reference, leading to a memory leak. In my profiling, I can see that the Fragment’s view is not being garbage collected because the ViewModel retains a reference to the LiveData subscriber. I tried using `viewLifecycleOwner` in the observer to ensure it only observes while the Fragment's view is in a valid state. I also made sure I'm not holding any strong references in the ViewModel itself. Is there something I'm missing here? Could this possibly be related to how the Navigation Component handles back stack and Fragments? Any insights or suggestions would be greatly appreciated! My development environment is Ubuntu. I'm working on a API that needs to handle this. I recently upgraded to Kotlin LTS. This is for a web app running on Ubuntu 22.04. I'd love to hear your thoughts on this. This is happening in both development and production on Debian. Any ideas what could be causing this?