FragmentStatePagerAdapter内存泄漏（带有viewpager的嵌套片段）

时间：2013-12-30 10:33:41

标签： android memory-leaks android-viewpager fragmentstatepageradapter

我的适配器中有“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一个viewpager。

我的设置如下：
 1.活动（托管片段A的空活动）
 2.片段A - 使用Fragmentstatepageradapter托管viewpager的片段。每个viewpager页面托管片段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，每次轮换发生时，它似乎增长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 - 出现同样的问题，因此不是造成问题的imageview 2.删除片段A和B并旋转活动。没有发生内存泄漏，因此不是活动 3.在任何方向改变之前使用MAT并且在旋转大约50次之后使用MAT以使堆积起来。 MAT显示了一个主要的嫌疑人，这是我的适配器类。它显示了7MB的保留堆（非常小的浅堆）观察者，如：

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相关的其他变量的活动。
2.配置更改后，我不重新创建适配器，而是使用旧的适配器连接到viewpager 3.如果我不重用旧适配器但在配置更改后创建新适配器，则内存泄漏消失 4.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？非常感谢任何帮助。

谢谢， JC

2 个答案:

答案 0 :(得分：31)

我有类似的内存泄漏现在已经解决了。

在我相应的片段A中，我使用this.getFragmentManager()而不是 this.getChildFragmentManager() 来实例化 FragmentStatePagerAdapter ，因为嵌套片段已到位。

如果这也解决了您的问题，请与我们联系。

答案 1 :(得分：0)

我有一个类似的问题，我使用ViewPager2，并且需要使用 getChildFragmentManager()而不是getSupportFragmentManager()，因为我想在一个分页器片段中用ViewPager引用回父片段（承载requireParentFragment()的父片段）

如果我使用，我会得到java.lang.IllegalStateException Fragment PageFragment{f152edf} (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使用的是Navigation组件，所以我不需要使用相同的Navigation组件的片段管理器来管理ViewPager子片段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

因此，为解决此问题，我清除了ViewPager以外的所有子片段；为此，我必须注册所有片段ID，并像下面那样覆盖containsItem() 

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();
    }

}

第二件事不是用ViewPager实例化活动的生命周期requireActivity().getLifecycle()适配器，而是像下面那样使用其片段getViewLifecycleOwner().getLifecycle()的生命周期

PageFragmentPagerAdapter mPagerAdapter = new PageFragmentPagerAdapter(
     getChildFragmentManager(), getViewLifecycleOwner().getLifecycle());
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