13

我的适配器中有“内存泄漏”（后面会解释引号）。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 的空活动）
2. Fragment A - 承载带有 Fragmentstatepageradapter 的 viewpager 的片段。每个 viewpager 页面都承载片段 B。
3. 片段 B - 包含图像视图的片段。

除非发生配置更改，否则一切正常。监控堆，每次轮换似乎都会增长 100 kb。手动 GCing 不会释放内存。

我尝试过的事情：
1. 用空白片段替换片段 B - 发生同样的问题，所以不是导致问题的图像视图。
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 次之后使用 MAT 来获得堆。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以及与 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。

有任何想法吗？将不胜感激任何帮助。

谢谢，JC

4

4 回答 4

38

我有类似的内存泄漏，现在已解决。

在我相应的 Fragment A 中，我使用而不是实例化FragmentStatePagerAdapter ，因为嵌套的 Fragment 已经到位。this.getFragmentManager()this.getChildFragmentManager()

请让我知道这是否也解决了您的问题。

于 2014-01-07T15:24:16.950 回答
3

我有一个类似的问题，我使用过ViewPager2，并且需要使用， getChildFragmentManager()而不是getSupportFragmentManager()因为我希望 PageFragment 引用父片段（承载ViewPager）requireParentFragment()

注意当我使用时getSupportFragmentManager()，我得到了java.lang.IllegalStateException Fragment PageFragment{f152edf} (af30cf2b-acf1-4930-9b83-03ac8144cfc6) f49} is not a child Fragment

我getChildFragmentManager()使用. ViewPager_getSupportFragmentManager()

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，我清除了所有已关闭的子片段ViewPager；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ViewPagerActivity 的生命周期来实例化适配器requireActivity().getLifecycle()，而是使用其片段的生命周期，getViewLifecycleOwner().getLifecycle()如下所示

PageFragmentPagerAdapter mPagerAdapter = new PageFragmentPagerAdapter(
     getChildFragmentManager(), getViewLifecycleOwner().getLifecycle());
于 2020-09-15T03:58:49.723 回答
0

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;
}
于 2021-10-21T20:51:17.500 回答
0

我有同样的问题。我设置了 null TabLayoutMediator 值，但在此之后泄漏并没有消失，我在 onDestroyView 中分离了 TabLayoutMediator，它对我有用。

override fun onDestroyView() {
    super.onDestroyView()

    mediator?.detach()
    mediator = null
    _binding = null
}
于 2021-12-01T13:37:20.023 回答