如何避免数组列表事件侦听器中的内存泄漏？

Question

我通过泄漏金丝雀收到内存泄漏通知，其中说我的片段实例由于eventlisteners和Arraylist.array的引用而泄漏。不知道如何解决这个问题，任何想法？

@Override
ArrayList<myInterface> getnewList() {
    ArrayList<myInterface> inst = new ArrayList<>();
    inst.addAll(myRepository.getList());
    inst.addAll(myRepository.getOtherList());
    Collections.sort(inst, myRepository.myComparator);
    return inst;
}

这是泄漏迹线，它指示泄漏：

In com.myproject.project2.alpha.debug:3.0.0:3000000.
* com.project.newzy.dashboard.myListFragment has leaked:
* GC ROOT static com.myproject.repository.myRepository.eventListeners
* references java.util.ArrayList.array
* references array java.lang.Object[].[0]
* leaks com.project.newzy.dashboard.myListFragment instance

* Retaining: 251 KB.
* Reference Key: cc806908-52f6-42f5-be98-b39665dfa218
* Device: samsung samsung SM-J327P j3popltespr
* Android Version: 6.0.1 API: 23 LeakCanary: 1.5.1 1be44b3
* Durations: watch=5463ms, gc=131ms, heap dump=3776ms, analysis=40370ms

* Details:
* Class com.myproject.repository.myRepository
|   static eventListeners = java.util.ArrayList@587750272 (0x23085b80)
|   static Comparator = com.myproject.repository.myRepository$5@587741136 (0x230837d0)
|   static $staticOverhead = byte[40]@584327169 (0x22d42001)
|   static initialized = true
|   static lock = java.lang.Object@587741152 (0x230837e0)
|   static cache = java.util.concurrent.ConcurrentHashMap@587732480 (0x23081600)
* Instance of java.util.ArrayList
|   static $staticOverhead = byte[16]@1893860329 (0x70e203e9)
|   static MIN_CAPACITY_INCREMENT = 12
|   static serialVersionUID = 8683452581122892189
|   array = java.lang.Object[12]@591375616 (0x233fad00)
|   size = 1
|   modCount = 1
|   shadow$_klass_ = java.util.ArrayList
|   shadow$_monitor_ = 0
* Array of java.lang.Object[]
|   [0] = com.project.newzy.dashboard.myListFragment@596231392 (0x2389c4e0)
|   [1] = null
|   [2] = null
|   [3] = null
|   [4] = null
|   [5] = null
|   [6] = null
|   [7] = null
|   [8] = null
|   [9] = null
|   [10] = null
|   [11] = null
* Instance of com.project.newzy.dashboard.myListFragment
|   static $staticOverhead = byte[16]@583464961 (0x22c6f801)
|   static serialVersionUID = 0
|   static $change = null
|   adapter = com.project.newzy.dashboard.DashboardAdapter@590877408 (0x233812e0)
|   myRepository = com.myproject.repository.myRepository@587661072 (0x2306ff10)
|   inst = java.util.ArrayList@591400160 (0x23400ce0)
|   emptyLayout = android.widget.RelativeLayout@593542144 (0x2360bc00)
|   emptyMessage = android.support.v7.widget.AppCompatTextView@593544192 (0x2360c400)
|   floatingActionButton = android.support.design.widget.FloatingActionButton@594071552 (0x2368d000)
|   roomList = com.project.gui.advancedrecyclerview.AdvancedRecyclerView@593541120 (0x2360b800)
|   selectedVGroupID = null
|   listAdapter = com.project.newzy.dashboard.DashboardAdapter@590877408 (0x233812e0)
|   listDivider = com.project.newzy.base.helpers.DividerItemDecoration@589723120 (0x232675f0)
|   listManager = android.support.v7.widget.LinearLayoutManager@591052128 (0x233abd60)
|   listView = com.project.gui.advancedrecyclerview.AdvancedRecyclerView@593541120 (0x2360b800)
|   mAdded = true
|   mAnimationInfo = null
|   mArguments = null
|   mBackStackNesting = 0
|   mCalled = true
|   mCheckedForLoaderManager = true
|   mChildFragmentManager = android.support.v4.app.FragmentManagerImpl@588818688 (0x2318a900)
|   mChildNonConfig = null
|   mContainer = android.support.v4.view.ViewPager@597927936 (0x23a3a800)
|   mContainerId = 2131755178
|   mDeferStart = false
|   mDetached = false
|   mFragmentId = 2131755178
|   mFragmentManager = android.support.v4.app.FragmentManagerImpl@598589728 (0x23adc120)
|   mFromLayout = false
|   mHasMenu = false
|   mHidden = false
|   mHiddenChanged = false
|   mHost = android.support.v4.app.FragmentActivity$HostCallbacks@598610224 (0x23ae1130)
|   mInLayout = false
|   mIndex = 1
|   mInnerView = android.widget.RelativeLayout@593536000 (0x2360a400)
|   mIsNewlyAdded = false
|   mLoaderManager = null
|   mLoadersStarted = true
|   mMenuVisible = true
|   mParentFragment = null
|   mPostponedAlpha = 0.0
|   mRemoving = false
|   mRestored = false
|   mRetainInstance = false
|   mRetaining = false
|   mSavedFragmentState = null
|   mSavedViewState = null
|   mState = 5
|   mTag = java.lang.String@590080848 (0x232beb50)
|   mTarget = null
|   mTargetIndex = -1
|   mTargetRequestCode = 0
|   mUserVisibleHint = true
|   mView = android.widget.RelativeLayout@593536000 (0x2360a400)
|   mWho = java.lang.String@591143744 (0x233c2340)
|   shadow$_klass_ = com.project.newzy.dashboard.myListFragment
|   shadow$_monitor_ = -2032154546
* Excluded Refs:
| Field: android.view.inputmethod.InputMethodManager.mNextServedView
| Field: android.view.inputmethod.InputMethodManager.mServedView
| Field: android.view.inputmethod.InputMethodManager.mServedInputConnection
| Field: android.view.inputmethod.InputMethodManager.mCurRootView
| Field: android.os.UserManager.mContext
| Field: android.net.ConnectivityManager.sInstance
| Field: android.view.Choreographer$FrameDisplayEventReceiver.mMessageQueue (always)
| Thread:FinalizerWatchdogDaemon (always)
| Thread:main (always)
| Thread:LeakCanary-Heap-Dump (always)
| Class:java.lang.ref.WeakReference (always)
| Class:java.lang.ref.SoftReference (always)
| Class:java.lang.ref.PhantomReference (always)
| Class:java.lang.ref.Finalizer (always)
| Class:java.lang.ref.FinalizerReference (always)

如果你们之前已经面对这个问题，请告诉我，并且有关于如何修复它的任何线索？

Answer 1

堆栈跟踪显示com.myproject.repository.myRepository持有对com.project.newzy.dashboard.myListFragment数组中eventListeners的引用。

我不确定你的myRepository究竟是什么，但是（可能用作Observable）它正在引用myListFragment（可能是Fragment） UI需要销毁。

要解决此问题，您需要确保在myListFragment即将被销毁时，它不再是eventListeners数组的一部分。只需从onPause中的数组中删除侦听器，然后将其注册回onResume。

Answer 2

您的myRepository类似乎拥有对Fragment实例myListFragment的引用。

我不知道myRepository的实现，但如果我可以猜测，这个类可能是一个Singleton类，所以它驻留在整个应用程序进程的内存中。 Fragment和Activity上下文是一个很大的内存块，因为Singleton类拥有对该内存的引用，垃圾收集器在完成其生命周期时无法清除Fragment / Activity内存，这意味着Fragment实例在整个应用程序生命周期中也将驻留在内存中。一篇关于meomory泄漏的博客：https://android.jlelse.eu/memory-leak-patterns-in-android-4741a7fcb570

我可以为您的问题推荐一个解决方法：

1. 让您的数据管理员课程变得愚蠢和无国籍。不要在数据管理器类中附加侦听器。相反，make API可以对数据进行CRUD操作，并且只在Fragment类中附加侦听器。触发事件时，请相应地调用数据管理器的方法。这使得您的数据管理器不会将逻辑与任何特定的Fragment类混合，如果您需要在项目中稍后删除Fragments，则不需要更改任何内容。

希望这有帮助。