NavContoller 片段泄漏
NavContoller Leaking in Fragment
当我使用 JetPack Navigation 在片段之间转换时，我无法找到发生泄漏的原因。
查看下面来自泄漏金丝雀的堆栈跟踪
D/LeakCanary:
┬───
│ GC Root: System class
│
├─ android.view.inputmethod.InputMethodManager class
│ Leaking: NO (InputMethodManager↓ is not leaking and a class is never leaking)
│ ↓ static InputMethodManager.sInstance
├─ android.view.inputmethod.InputMethodManager instance
│ Leaking: NO (DecorView↓ is not leaking and InputMethodManager is a singleton)
│ ↓ InputMethodManager.mNextServedView
├─ com.android.internal.policy.DecorView instance
│ Leaking: NO (LinearLayout↓ is not leaking and View attached)
│ View is part of a window view hierarchy
D/LeakCanary: │ View.mAttachInfo is not null (view attached)
│ View.mWindowAttachCount = 1
│ mContext instance of com.android.internal.policy.DecorContext, wrapping activity com.carepay.flows.CarePayActivity
│ with mDestroyed = false
│ ↓ DecorView.mContentRoot
├─ android.widget.LinearLayout instance
│ Leaking: NO (CarePayActivity↓ is not leaking and View attached)
│ View is part of a window view hierarchy
│ View.mAttachInfo is not null (view attached)
│ View.mWindowAttachCount = 1
│ mContext instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ LinearLayout.mContext
├─ com.carepay.flows.CarePayActivity instance
│ Leaking: NO (NavHostFragment↓ is not leaking and Activity#mDestroyed is false)
│ mApplication instance of com.carepay.MemberApp
│ mBase instance of androidx.appcompat.view.ContextThemeWrapper, not wrapping known Android context
│ ↓ CarePayActivity.mFragments
├─ androidx.fragment.app.FragmentController instance
│ Leaking: NO (NavHostFragment↓ is not leaking)
│ ↓ FragmentController.mHost
├─ androidx.fragment.app.FragmentActivity$HostCallbacks instance
│ Leaking: NO (NavHostFragment↓ is not leaking)
│ this[=10=] instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mActivity instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mContext instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ FragmentActivity$HostCallbacks.mFragmentManager
D/LeakCanary: ├─ androidx.fragment.app.FragmentManagerImpl instance
│ Leaking: NO (NavHostFragment↓ is not leaking)
│ ↓ FragmentManagerImpl.mPrimaryNav
├─ androidx.navigation.fragment.NavHostFragment instance
│ Leaking: NO (Fragment#mFragmentManager is not null)
│ ↓ NavHostFragment.mNavController
│ ~~~~~~~~~~~~~~
├─ androidx.navigation.NavHostController instance
│ Leaking: UNKNOWN
│ Retaining 1313968 bytes in 7994 objects
│ mActivity instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mContext instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ NavHostController.mOnDestinationChangedListeners
│ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
├─ java.util.concurrent.CopyOnWriteArrayList instance
│ Leaking: UNKNOWN
│ Retaining 1302920 bytes in 7681 objects
│ ↓ CopyOnWriteArrayList.elements
│ ~~~~~~~~
├─ java.lang.Object[] array
│ Leaking: UNKNOWN
│ Retaining 1302896 bytes in 7679 objects
│ ↓ Object[].[2]
D/LeakCanary: │ ~~~
├─ androidx.navigation.ui.ActionBarOnDestinationChangedListener instance
│ Leaking: UNKNOWN
│ Retaining 5425 bytes in 190 objects
│ mActivity instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mContext instance of dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper, wrapping
│ activity com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ ActionBarOnDestinationChangedListener.mContext
│ ~~~~~~~~
├─ dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper instance
│ Leaking: UNKNOWN
│ Retaining 4365 bytes in 162 objects
│ mBase instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ViewComponentManager$FragmentContextWrapper wraps an Activity with Activity.mDestroyed false
│ ↓ ViewComponentManager$FragmentContextWrapper.fragment
│ ~~~~~~~~
╰→ com.carepay.flows.treatmentdetail.TreatmentDetailFragment instance
Leaking: YES (ObjectWatcher was watching this because com.carepay.flows.treatmentdetail.TreatmentDetailFragment
received Fragment#onDestroy() callback and Fragment#mFragmentManager is null)
Retaining 3565 bytes in 129 objects
key = 3b650fce-861c-463b-8ccb-78255dfc535a
watchDurationMillis = 22434
retainedDurationMillis = 16751
componentContext instance of dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper,
wrapping activity com.carepay.flows.CarePayActivity with mDestroyed = false
所有片段转换都会引发此泄漏，因此我将分享所选堆栈跟踪中片段的片段。
TreatmentDetailFragment
class TreatmentDetailFragment : OverlayFragment(R.layout.fragment_treatment_detail) {
private val binding get() = (_binding as FragmentTreatmentDetailBinding?)!!
private val args: TreatmentDetailFragmentArgs by navArgs()
private val viewModel by viewModels<TreatmentDetailViewModel>()
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
_binding = FragmentTreatmentDetailBinding.inflate(inflater, container, false)
val adapter = ItemsAdapter()
binding.treatmentItems.adapter = adapter
setupObservers(adapter)
viewModel.fetchTreatment(args.treatmentId, lifecycle)
return binding.root
}
private fun setupObservers(adapter: ItemsAdapter) {
viewModel.treatment.observe(viewLifecycleOwner){ treatment ->
binding.titleView.text = getString(R.string.treatment, treatment.treatmentCode)
binding.treatment = treatment
adapter.items = treatment.getItems()
adapter.notifyDataSetChanged()
}
}
}
OverlayFragment
abstract class OverlayFragment(@LayoutRes layoutResource: Int) : BaseFragment(layoutResource) {
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val activity = requireActivity() as CarePayActivity
activity.showBackButton(true)
activity.showCloseIcon(true)
activity.showBottomNavigation(View.GONE)
}
}
基础片段
@AndroidEntryPoint
abstract class BaseFragment(@LayoutRes layoutResource: Int) : Fragment(layoutResource) {
@Inject
protected lateinit var memberSettingsRepository: MemberSettingsRepository
protected var _binding: ViewBinding? = null
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val navController = findNavController()
val appBarConfiguration = AppBarConfiguration(
setOf(
R.id.navigation_health,
R.id.navigation_benefits,
R.id.navigation_clinics,
R.id.navigation_account
)
)
val toolbar = view.findViewById<Toolbar>(R.id.toolbar)
val activity = requireActivity() as CarePayActivity
activity.setSupportActionBar(toolbar)
activity.setupActionBarWithNavController(navController, appBarConfiguration)
}
}
Activity
@AndroidEntryPoint
class CarePayActivity : AppCompatActivity() {
@Inject
lateinit var memberSettingsRepository: MemberSettingsRepository
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_carepay)
val navView: BottomNavigationView = findViewById(R.id.nav_view)
val navController = findNavController(R.id.nav_host_fragment)
val inflater = navController.navInflater
val graph = inflater.inflate(R.navigation.mobile_navigation)
when {
intent.hasExtra(RESUMED) -> {
graph.startDestination = R.id.navigation_health
}
else -> {
graph.startDestination = R.id.navigation_setup
}
}
navController.graph = graph
navView.setupWithNavController(navController)
}
override fun onSupportNavigateUp(): Boolean {
return findNavController(R.id.nav_host_fragment).navigateUp() || super.onSupportNavigateUp()
}
override fun onBackPressed() {
val currentDestination = findNavController(R.id.nav_host_fragment).currentDestination
when (currentDestination?.id) {
R.id.navigation_health -> {
val dialog = getDialog(
getString(R.string.exit),
getString(R.string.exit_message, getString(R.string.app_name)),
getString(R.string.yes),
getString(R.string.no),
object : DialogButtonEvents {
override fun onButtonClicked(id: Int) {
if (id == R.id.positiveButton) {
finish()
}
}
})
dialog.show()
dialog.window?.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT));
}
else -> {
findNavController(R.id.nav_host_fragment).navigateUp()
}
}
}
}
注意：碎片比他们的观点更有效。确保清除片段的 onDestroyView() 方法中对绑定 class 实例的所有引用。 link
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
val toolbar = view.findViewById<Toolbar>(R.id.toolbar)
val activity = requireActivity() as CarePayActivity
activity.setSupportActionBar(toolbar)
activity.setupActionBarWithNavController(navController, appBarConfiguration)
这些行会导致泄漏，因为您将属于 Fragment 的 navController 提供给 Activity，因此每当 Fragment 被销毁时，它都会由于 navController.
无法取消引用
当我使用 JetPack Navigation 在片段之间转换时，我无法找到发生泄漏的原因。
查看下面来自泄漏金丝雀的堆栈跟踪
D/LeakCanary:
┬───
│ GC Root: System class
│
├─ android.view.inputmethod.InputMethodManager class
│ Leaking: NO (InputMethodManager↓ is not leaking and a class is never leaking)
│ ↓ static InputMethodManager.sInstance
├─ android.view.inputmethod.InputMethodManager instance
│ Leaking: NO (DecorView↓ is not leaking and InputMethodManager is a singleton)
│ ↓ InputMethodManager.mNextServedView
├─ com.android.internal.policy.DecorView instance
│ Leaking: NO (LinearLayout↓ is not leaking and View attached)
│ View is part of a window view hierarchy
D/LeakCanary: │ View.mAttachInfo is not null (view attached)
│ View.mWindowAttachCount = 1
│ mContext instance of com.android.internal.policy.DecorContext, wrapping activity com.carepay.flows.CarePayActivity
│ with mDestroyed = false
│ ↓ DecorView.mContentRoot
├─ android.widget.LinearLayout instance
│ Leaking: NO (CarePayActivity↓ is not leaking and View attached)
│ View is part of a window view hierarchy
│ View.mAttachInfo is not null (view attached)
│ View.mWindowAttachCount = 1
│ mContext instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ LinearLayout.mContext
├─ com.carepay.flows.CarePayActivity instance
│ Leaking: NO (NavHostFragment↓ is not leaking and Activity#mDestroyed is false)
│ mApplication instance of com.carepay.MemberApp
│ mBase instance of androidx.appcompat.view.ContextThemeWrapper, not wrapping known Android context
│ ↓ CarePayActivity.mFragments
├─ androidx.fragment.app.FragmentController instance
│ Leaking: NO (NavHostFragment↓ is not leaking)
│ ↓ FragmentController.mHost
├─ androidx.fragment.app.FragmentActivity$HostCallbacks instance
│ Leaking: NO (NavHostFragment↓ is not leaking)
│ this[=10=] instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mActivity instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mContext instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ FragmentActivity$HostCallbacks.mFragmentManager
D/LeakCanary: ├─ androidx.fragment.app.FragmentManagerImpl instance
│ Leaking: NO (NavHostFragment↓ is not leaking)
│ ↓ FragmentManagerImpl.mPrimaryNav
├─ androidx.navigation.fragment.NavHostFragment instance
│ Leaking: NO (Fragment#mFragmentManager is not null)
│ ↓ NavHostFragment.mNavController
│ ~~~~~~~~~~~~~~
├─ androidx.navigation.NavHostController instance
│ Leaking: UNKNOWN
│ Retaining 1313968 bytes in 7994 objects
│ mActivity instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mContext instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ NavHostController.mOnDestinationChangedListeners
│ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
├─ java.util.concurrent.CopyOnWriteArrayList instance
│ Leaking: UNKNOWN
│ Retaining 1302920 bytes in 7681 objects
│ ↓ CopyOnWriteArrayList.elements
│ ~~~~~~~~
├─ java.lang.Object[] array
│ Leaking: UNKNOWN
│ Retaining 1302896 bytes in 7679 objects
│ ↓ Object[].[2]
D/LeakCanary: │ ~~~
├─ androidx.navigation.ui.ActionBarOnDestinationChangedListener instance
│ Leaking: UNKNOWN
│ Retaining 5425 bytes in 190 objects
│ mActivity instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ mContext instance of dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper, wrapping
│ activity com.carepay.flows.CarePayActivity with mDestroyed = false
│ ↓ ActionBarOnDestinationChangedListener.mContext
│ ~~~~~~~~
├─ dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper instance
│ Leaking: UNKNOWN
│ Retaining 4365 bytes in 162 objects
│ mBase instance of com.carepay.flows.CarePayActivity with mDestroyed = false
│ ViewComponentManager$FragmentContextWrapper wraps an Activity with Activity.mDestroyed false
│ ↓ ViewComponentManager$FragmentContextWrapper.fragment
│ ~~~~~~~~
╰→ com.carepay.flows.treatmentdetail.TreatmentDetailFragment instance
Leaking: YES (ObjectWatcher was watching this because com.carepay.flows.treatmentdetail.TreatmentDetailFragment
received Fragment#onDestroy() callback and Fragment#mFragmentManager is null)
Retaining 3565 bytes in 129 objects
key = 3b650fce-861c-463b-8ccb-78255dfc535a
watchDurationMillis = 22434
retainedDurationMillis = 16751
componentContext instance of dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper,
wrapping activity com.carepay.flows.CarePayActivity with mDestroyed = false
所有片段转换都会引发此泄漏，因此我将分享所选堆栈跟踪中片段的片段。
TreatmentDetailFragment
class TreatmentDetailFragment : OverlayFragment(R.layout.fragment_treatment_detail) {
private val binding get() = (_binding as FragmentTreatmentDetailBinding?)!!
private val args: TreatmentDetailFragmentArgs by navArgs()
private val viewModel by viewModels<TreatmentDetailViewModel>()
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
_binding = FragmentTreatmentDetailBinding.inflate(inflater, container, false)
val adapter = ItemsAdapter()
binding.treatmentItems.adapter = adapter
setupObservers(adapter)
viewModel.fetchTreatment(args.treatmentId, lifecycle)
return binding.root
}
private fun setupObservers(adapter: ItemsAdapter) {
viewModel.treatment.observe(viewLifecycleOwner){ treatment ->
binding.titleView.text = getString(R.string.treatment, treatment.treatmentCode)
binding.treatment = treatment
adapter.items = treatment.getItems()
adapter.notifyDataSetChanged()
}
}
}
OverlayFragment
abstract class OverlayFragment(@LayoutRes layoutResource: Int) : BaseFragment(layoutResource) {
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val activity = requireActivity() as CarePayActivity
activity.showBackButton(true)
activity.showCloseIcon(true)
activity.showBottomNavigation(View.GONE)
}
}
基础片段
@AndroidEntryPoint
abstract class BaseFragment(@LayoutRes layoutResource: Int) : Fragment(layoutResource) {
@Inject
protected lateinit var memberSettingsRepository: MemberSettingsRepository
protected var _binding: ViewBinding? = null
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val navController = findNavController()
val appBarConfiguration = AppBarConfiguration(
setOf(
R.id.navigation_health,
R.id.navigation_benefits,
R.id.navigation_clinics,
R.id.navigation_account
)
)
val toolbar = view.findViewById<Toolbar>(R.id.toolbar)
val activity = requireActivity() as CarePayActivity
activity.setSupportActionBar(toolbar)
activity.setupActionBarWithNavController(navController, appBarConfiguration)
}
}
Activity
@AndroidEntryPoint
class CarePayActivity : AppCompatActivity() {
@Inject
lateinit var memberSettingsRepository: MemberSettingsRepository
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_carepay)
val navView: BottomNavigationView = findViewById(R.id.nav_view)
val navController = findNavController(R.id.nav_host_fragment)
val inflater = navController.navInflater
val graph = inflater.inflate(R.navigation.mobile_navigation)
when {
intent.hasExtra(RESUMED) -> {
graph.startDestination = R.id.navigation_health
}
else -> {
graph.startDestination = R.id.navigation_setup
}
}
navController.graph = graph
navView.setupWithNavController(navController)
}
override fun onSupportNavigateUp(): Boolean {
return findNavController(R.id.nav_host_fragment).navigateUp() || super.onSupportNavigateUp()
}
override fun onBackPressed() {
val currentDestination = findNavController(R.id.nav_host_fragment).currentDestination
when (currentDestination?.id) {
R.id.navigation_health -> {
val dialog = getDialog(
getString(R.string.exit),
getString(R.string.exit_message, getString(R.string.app_name)),
getString(R.string.yes),
getString(R.string.no),
object : DialogButtonEvents {
override fun onButtonClicked(id: Int) {
if (id == R.id.positiveButton) {
finish()
}
}
})
dialog.show()
dialog.window?.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT));
}
else -> {
findNavController(R.id.nav_host_fragment).navigateUp()
}
}
}
}
注意：碎片比他们的观点更有效。确保清除片段的 onDestroyView() 方法中对绑定 class 实例的所有引用。 link
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
val toolbar = view.findViewById<Toolbar>(R.id.toolbar)
val activity = requireActivity() as CarePayActivity
activity.setSupportActionBar(toolbar)
activity.setupActionBarWithNavController(navController, appBarConfiguration)
这些行会导致泄漏，因为您将属于 Fragment 的 navController 提供给 Activity，因此每当 Fragment 被销毁时，它都会由于 navController.