Memory Leak RecyclerView Adapter

Reproducible Sample with Fix

Video Instructions: https://www.youtube.com/c/awesomedevnotes

Code

Only the relevant and important code is shown in README. Refer to entire source code for more details.

A1ListFragment.kt

// Important part is where adapter is set to null in `onDestroyView`

/** Fragment containing RecyclerView */
class A1ListFragment : Fragment(), A1ListRecyclerViewAdapter.OnA1ListItemClickedListener {

    private var _binding: FragmentListA1Binding? = null
    private val binding get() = _binding!!

    // Making RecyclerView adapter nullable so we could set it to null in onDestroyView
    private var a1ListRecyclerViewAdapter: A1ListRecyclerViewAdapter? = null

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        _binding = FragmentListA1Binding.inflate(inflater, container, false)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        setup()
    }

    private fun setup() {
        setupRecyclerView()
    }

    private fun setupRecyclerView() {
        a1ListRecyclerViewAdapter = A1ListRecyclerViewAdapter(this)
        binding.a1ListRecyclerView.adapter = a1ListRecyclerViewAdapter
    }

    override fun onDestroyView() {
        // Important to set fields to `null` to prevent memory leaks.
        // We are setting fields to null before `super.onDestroyView()` because official ViewBinding
        // sample, Mozilla Fenix app also do that. I do not know the exact reason.

        a1ListRecyclerViewAdapter = null
        _binding = null
        super.onDestroyView()
    }

    override fun onA1ListItemClicked() {
        findNavController().navigate(R.id.action_a1ListFragment_to_a2DetailFragment)
    }
}

Dependencies

debugImplementation "com.squareup.leakcanary:leakcanary-android:2.7"

// https://github.com/square/leakcanary - To detect memory leaks

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