FragmentStatePagerAdapter 内存泄漏(带有 viewpager 的嵌套片段)
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【中文标题】FragmentStatePagerAdapter 内存泄漏(带有 viewpager 的嵌套片段)【英文标题】:FragmentStatePagerAdapter memory leak (nested fragments with viewpager) 【发布时间】:2014-01-17 05:35:07 【问题描述】:我的适配器中有一个“内存泄漏”(引用将在后面解释)。我目前正在使用嵌套片段来托管 viewpager。
我的设置如下: 1. Activity(承载 Fragment A 的空 Activity) 2. 片段 A - 使用 Fragmentstatepageradapter 托管 viewpager 的片段。每个浏览器页面都承载片段 B。 3. Fragment B - 一个包含 imageview 的片段。
一切都很好,除非发生配置更改。监控堆,似乎每次旋转都会增长 100 kb。手动 GCing 不会释放内存。
我尝试过的事情: 1. 将 Fragment B 替换为空白片段 - 会出现同样的问题,因此不是导致问题的 imageview。 2. 删除片段 A 和 B 并旋转活动。没有发生内存泄漏,所以它不是活动。 3. 在任何方向改变之前和旋转大约 50 次后使用 MAT 来获取堆。 MAT 显示 1 个主要嫌疑人是我的适配器类。它显示了 7MB 的保留堆(非常小的浅堆)的观察者,如下所示:
array java.util.ArrayList @ 0x42079938 24 7,000,832
.\mObservers android.database.DataSetObservable @ 0x42053508 16 7,000,848
..\mObservable com.example.main.Adapter@ 0x4205a048 40 7,001,416
为什么我在片段中使用 viewpager: 1. 我想通过设置 setretaininstance(true) 来保持适配器的状态和与 viewpager 相关的其他变量。 2. 配置更改后,我没有重新创建适配器,而是使用旧适配器附加到 viewpager。 3.如果我不重用旧适配器而是在配置更改后创建新适配器,内存泄漏就会消失。 4.我关闭活动并返回上一个活动后,内存泄漏也消失了。
有什么想法吗?将不胜感激。
谢谢, JC
【问题讨论】:
【参考方案1】:我有一个类似的内存泄漏,现在已经解决了。
在我对应的 Fragment A 中,我使用 this.getFragmentManager()
而不是 this.getChildFragmentManager()
实例化 FragmentStatePagerAdapter,因为嵌套的 Fragment 已经到位。
如果这也解决了您的问题,请告诉我。
【讨论】:
谢谢你!我自己永远也想不通(尽管这是合乎逻辑的)。 应该被标记为正确的遮阳篷。谢谢! 你能告诉我在哪里放 getChildFragmentManager() 我正在执行以下操作: MainActivity: fragmentAdapter = new FragmentAdapter(getSupportFragmentManager());并在片段适配器中: public FragmentAdapter(FragmentManager fm) super(fm); 请在您的 MainActivity 中尝试以下操作:fragmentAdapter = new FragmentAdapter(getChildFragmentManager()); 出色的修复,非常感谢。【参考方案2】:我有类似的问题,我用ViewPager2
,需要用
getChildFragmentManager()
而不是 getSupportFragmentManager()
,因为我希望 PageFragment 使用requireParentFragment()
引用父片段(承载ViewPager
)
注意当我使用getSupportFragmentManager()
时,我得到了java.lang.IllegalStateException Fragment PageFragmentf152edf (af30cf2b-acf1-4930-9b83-03ac8144cfc6) f49 is not a child Fragment
我使用getChildFragmentManager()
的另一个原因是,因为我正在使用导航组件,所以我不需要使用导航组件的相同片段管理器getSupportFragmentManager()
来管理ViewPager
子片段。
这是 LeakCanary 日志
2020-09-15 05:39:33.461 9611-9689/.... D/LeakCanary: ┬───
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ GC Root: Local variable in native code
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ android.os.HandlerThread instance
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: NO (PathClassLoader↓ is not leaking)
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Thread name: 'LeakCanary-Heap-Dump'
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ↓ HandlerThread.contextClassLoader
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ dalvik.system.PathClassLoader instance
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: NO (InternalLeakCanary↓ is not leaking and A ClassLoader is never leaking)
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ↓ PathClassLoader.runtimeInternalObjects
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ java.lang.Object[] array
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: NO (InternalLeakCanary↓ is not leaking)
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ↓ Object[].[597]
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ leakcanary.internal.InternalLeakCanary class
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: NO (MainActivity↓ is not leaking and a class is never leaking)
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ↓ static InternalLeakCanary.resumedActivity
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ .....ui.MainActivity instance
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: NO (Activity#mDestroyed is false)
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ↓ MainActivity.mLifecycleRegistry
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ~~~~~~~~~~~~~~~~~~
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ androidx.lifecycle.LifecycleRegistry instance
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ↓ LifecycleRegistry.mObserverMap
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ ~~~~~~~~~~~~
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: ├─ androidx.arch.core.internal.FastSafeIterableMap instance
2020-09-15 05:39:33.462 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ↓ FastSafeIterableMap.mHashMap
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ~~~~~~~~
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: ├─ java.util.HashMap instance
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ↓ HashMap.table
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ~~~~~
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: ├─ java.util.HashMap$Node[] array
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ↓ HashMap$Node[].[5]
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ~~~
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: ├─ java.util.HashMap$Node instance
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ↓ HashMap$Node.key
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ~~~
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: ├─ androidx.viewpager2.adapter.FragmentStateAdapter$FragmentMaxLifecycleEnforcer$3 instance
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ Anonymous class implementing androidx.lifecycle.LifecycleEventObserver
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ↓ FragmentStateAdapter$FragmentMaxLifecycleEnforcer$3.this$1
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ~~~~~~
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: ├─ androidx.viewpager2.adapter.FragmentStateAdapter$FragmentMaxLifecycleEnforcer instance
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ Leaking: UNKNOWN
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ↓ FragmentStateAdapter$FragmentMaxLifecycleEnforcer.mViewPager
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: │ ~~~~~~~~~~
2020-09-15 05:39:33.463 9611-9689/.... D/LeakCanary: ├─ androidx.viewpager2.widget.ViewPager2 instance
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ Leaking: YES (View detached and has parent)
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ mContext instance of .....ui.MainActivity with mDestroyed = false
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ View#mParent is set
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ View#mAttachInfo is null (view detached)
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ View.mID = R.id.viewpager
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ View.mWindowAttachCount = 1
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ ↓ ViewPager2.mParent
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: ├─ androidx.coordinatorlayout.widget.CoordinatorLayout instance
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ Leaking: YES (ViewPager2↑ is leaking and View detached and has parent)
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ mContext instance of .....ui.MainActivity with mDestroyed = false
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ View#mParent is set
2020-09-15 05:39:33.465 9611-9689/.... D/LeakCanary: │ View#mAttachInfo is null (view detached)
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: │ View.mWindowAttachCount = 1
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: │ ↓ CoordinatorLayout.mParent
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: ╰→ androidx.drawerlayout.widget.DrawerLayout instance
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: Leaking: YES (ObjectWatcher was watching this because .....ui.fragments.ReadFragment received Fragment#onDestroyView() callback (references to its views should be cleared to prevent leaks))
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: key = e3b96092-06d5-48ae-93bf-b38680cc0c35
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: watchDurationMillis = 6413
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: retainedDurationMillis = 1400
2020-09-15 05:39:33.466 9611-9689/.... D/LeakCanary: mContext instance of .....ui.MainActivity with mDestroyed = false
2020-09-15 05:39:33.467 9611-9689/.... D/LeakCanary: View#mParent is null
2020-09-15 05:39:33.467 9611-9689/.... D/LeakCanary: View#mAttachInfo is null (view detached)
2020-09-15 05:39:33.467 9611-9689/.... D/LeakCanary: View.mID = R.id.drawer_layout
所以,为了解决这个问题,我清除了所有已离开 ViewPager
的子片段;为此,我必须注册所有片段 ID,并覆盖 containsItem()
以清除它们,如下所示:
public class PageFragmentPagerAdapter extends FragmentStateAdapter
private FragmentManager mFragmentMgr;
private List<Integer> currentPageIds = new ArrayList<>();
public PageFragmentPagerAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle)
super(fragmentManager, lifecycle);
mFragmentMgr = fragmentManager;
@NonNull
@Override
public Fragment createFragment(int position)
PageFragment pageFragment = PageFragment.newInstance(position);
currentPageIds.add(position);
return pageFragment;
@Override
public long getItemId(int position)
return position;
@Override
public int getItemCount()
return N_PAGES;
@Override
public boolean containsItem(long itemId)
for (Integer id : currentPageIds)
if (id == itemId)
currentPageIds.remove(Integer.valueOf(String.valueOf(itemId)));
clearFragment(id);
break;
return super.containsItem(itemId);
private void clearFragment(int fragmentId)
FragmentTransaction transaction = mFragmentMgr.beginTransaction();
PageFragment fragment = (PageFragment) mFragmentMgr.findFragmentByTag("f" + fragmentId);
if (fragment != null)
transaction.remove(fragment);
transaction.commitAllowingStateLoss();
第二件事不要使用requireActivity().getLifecycle()
的活动生命周期实例化ViewPager
适配器,而是使用其片段getViewLifecycleOwner().getLifecycle()
的生命周期,如下所示
PageFragmentPagerAdapter mPagerAdapter = new PageFragmentPagerAdapter(
getChildFragmentManager(), getViewLifecycleOwner().getLifecycle());
【讨论】:
【参考方案3】:当 Android 配置发生变化时,例如屏幕旋转,Activity 和 Fragment 会重新创建,因此您需要干净的引用以避免内存泄漏。
例如:
public void onDestroyView()
super.onDestroyView();
if(viewPager != null)
viewPager.setAdapter(null);
viewPager.removeOnPageChangeListener(null);
if(tabLayout != null)
tabLayout.clearOnTabSelectedListeners();
tabLayout.setupWithViewPager(null);
viewPager = null;
tabLayout = null;
【讨论】:
【参考方案4】:我有同样的问题。我设置了 null TabLayoutMediator 值,但此后泄漏并没有消失,我在 onDestroyView 中分离了 TabLayoutMediator,它对我有用。
override fun onDestroyView()
super.onDestroyView()
mediator?.detach()
mediator = null
_binding = null
【讨论】:
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