Fragments memory leaks

Question

I have only one activity and all navigation is solved through fragments. If I open the fragment and come back, the fragment will be still in memory and memory will be growing.

What am I doing wrong? Do I have to manually remove listeners? In the onDestroy method, getView is already null.

How I add fragments:

    fun replaceFragment(
        fragmentManager: FragmentManager?,
        fragment: Fragment?,
        frameId: Int,
        tag: String?
    ) {
        if (fragmentManager != null && fragment != null) {
            val previousFragment = fragmentManager.findFragmentById(frameId)
            if (fragment != previousFragment) {
                val transaction = fragmentManager.beginTransaction()
                transaction.replace(frameId, fragment, tag)
                transaction.addToBackStack(tag)
                transaction.commitAllowingStateLoss()
            }
        }
    }

Fragment close by the back button:

EDIT: How I create Fragment

    companion object {
        fun create(number: Long): ManageUnitFragment {
            val fragment = ManageUnitFragment()

            val params = Bundle()
            params.putLong(Keys.Number, number)
            fragment.arguments = params

            return fragment
        }
    }

How I set Listeners (on buttons)

import kotlinx.android.synthetic.main.myFragment.*

        vMyButton.setOnClickListener {
            myAction()
        }

EDIT If I remove this line vButtonClose.setOnClickListener... , the ManageUnitFragments will no longer be in the heap dump.

ManageUnitFragment:

import kotlinx.android.synthetic.main.fragment_manage_unit.*

class ManageUnitFragment : Fragment() {

    override fun onCreateView(
            inflater: LayoutInflater,
            container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_manage_unit, container, false)
    }

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)
        vButtonClose.setOnClickListener {
            activity?.onBackPressed()
        }
    }

    companion object {
        fun create(unitNumber: Long, wagonWagonUnit: WagonUnit): ManageUnitFragment {
            val fragment = ManageUnitFragment()
            return fragment
        }
    }
}

Answer 1

Have you tried to add 'many' fragments? Do you actually get OutOfMemoryException ?

Maybe they just remain in memory until more of it is needed. Then they will be garbage collected.