Question

刚开始与Leak Canary一起了解内存泄漏，因此请谅解或误解任何内容。泄漏金丝雀告诉我内存泄漏，我将其缩小到这一行

NavigationUI.setupActionBarWithNavController(
    it,
    navController
)

导航控制器被调用并设置为这样的变量

val navController = findNavController(this@PokemonDetailFragment)

“ it”是我的活动投射到应用兼容活动，完整的代码段如下所示：

    mainActivity = (activity as AppCompatActivity)
    mainActivity?.let {
        it.setSupportActionBar(toolbar)
        val navController = findNavController(this@PokemonDetailFragment)
        NavigationUI.setupActionBarWithNavController(
            it,
            navController
        )
    }

我已经尝试了三件事：1.注入活动，2.将活动设置为全局可为空的变量，并在onDestroyView中将其设置为null，并且3.尝试使用NavigationUI.setupWithNavController而不是使用setActionBarWithNavController的方法。工具栏和导航控制器

    NavigationUI.setupWithNavController(
        binding.toolbar,
        findNavController(this@PokemonDetailFragment)
    )

但这些都不能解决问题。

删除第一个代码块肯定可以消除泄漏，但是Leak Canary并没有将泄漏显示为第三方库，并且确实说这是我的代码下面的变量是堆转储

    ```
    ┬───
    │ GC Root: Local variable in native code
    │
    ├─ android.os.HandlerThread instance
    │    Leaking: NO (PathClassLoader↓ is not leaking)
    │    Thread name: 'LeakCanary-Heap-Dump'
    │    ↓ HandlerThread.contextClassLoader
    ├─ dalvik.system.PathClassLoader instance
    │    Leaking: NO (InternalLeakCanary↓ is not leaking and A ClassLoader is never leaking)
    │    ↓ PathClassLoader.runtimeInternalObjects
    ├─ java.lang.Object[] array
    │    Leaking: NO (InternalLeakCanary↓ is not leaking)
    │    ↓ Object[].[502]
    ├─ leakcanary.internal.InternalLeakCanary class
    │    Leaking: NO (MainActivity↓ is not leaking and a class is never leaking)
    │    ↓ static InternalLeakCanary.resumedActivity
    ├─ com.sealstudios.pokemonApp.MainActivity instance
    │    Leaking: NO (FragmentContainerView↓ is not leaking and Activity#mDestroyed is false)
    │    ↓ MainActivity._binding
    ├─ com.sealstudios.pokemonApp.databinding.ActivityMainBinding instance
    │    Leaking: NO (FragmentContainerView↓ is not leaking)
    │    ↓ ActivityMainBinding.navHostFragment
    ├─ androidx.fragment.app.FragmentContainerView instance
    │    Leaking: NO (View attached)
    │    mContext instance of com.sealstudios.pokemonApp.MainActivity with mDestroyed = false
    │    View.parent androidx.constraintlayout.widget.ConstraintLayout attached as well
    │    View#mParent is set
    │    View#mAttachInfo is not null (view attached)
    │    View.mID = R.id.nav_host_fragment
    │    View.mWindowAttachCount = 1
    │    ↓ FragmentContainerView.mKeyedTags
    │                            ~~~~~~~~~~
    ├─ android.util.SparseArray instance
    │    Leaking: UNKNOWN
    │    ↓ SparseArray.mValues
    │                  ~~~~~~~
    ├─ java.lang.Object[] array
    │    Leaking: UNKNOWN
    │    ↓ Object[].[0]
    │               ~~~
    ├─ androidx.navigation.NavHostController instance
    │    Leaking: UNKNOWN
    │    ↓ NavHostController.mOnDestinationChangedListeners
    │                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ├─ java.util.concurrent.CopyOnWriteArrayList instance
    │    Leaking: UNKNOWN
    │    ↓ CopyOnWriteArrayList.array
    │                           ~~~~~
    ├─ java.lang.Object[] array
    │    Leaking: UNKNOWN
    │    ↓ Object[].[1]
    │               ~~~
    ├─ androidx.navigation.ui.ActionBarOnDestinationChangedListener instance
    │    Leaking: UNKNOWN
    │    ↓ ActionBarOnDestinationChangedListener.mContext
    │                                            ~~~~~~~~
    ├─ android.view.ContextThemeWrapper instance
    │    Leaking: UNKNOWN
    │    ContextThemeWrapper wraps an Activity with Activity.mDestroyed false
    │    ↓ ContextThemeWrapper.mBase
    │                          ~~~~~
    ├─ dagger.hilt.android.internal.managers.ViewComponentManager$FragmentContextWrapper instance
    │    Leaking: UNKNOWN
    │    ViewComponentManager$FragmentContextWrapper wraps an Activity with Activity.mDestroyed false
    │    ↓ ViewComponentManager$FragmentContextWrapper.fragment
    │                                                  ~~~~~~~~
    ╰→ com.sealstudios.pokemonApp.ui.PokemonDetailFragment instance
         Leaking: YES (ObjectWatcher was watching this because com.sealstudios.pokemonApp.ui.PokemonDetailFragment received Fragment#onDestroy() callback and Fragment#mFragmentManager is null)
         key = 724affdf-d1ac-47ff-82b8-6907ced5b666
         watchDurationMillis = 9052
         retainedDurationMillis = 4051

    METADATA

    Build.VERSION.SDK_INT: 29
    Build.MANUFACTURER: Google
    LeakCanary version: 2.4
    App process name: com.sealstudios.pokemonApp
        Analysis duration: 14474 ms```

感谢任何帮助，我只想设置需要AppCompatActivity的工具栏，然后正确处理它或允许系统执行此操作

我正在使用Hilt，尽管我的堆中确实提到了ContextThemeWrapper-https://github.com/google/dagger/issues/2070

，但我不确定这是否相关。

Answer 1

对此一无所知，手动进行设置可以消除内存泄漏

@SuppressLint("DefaultLocale")
private fun setActionBar() {
    binding.toolbar.outlineProvider = null
    binding.appBarLayout.outlineProvider = null
    (activity as AppCompatActivity).setSupportActionBar(binding.toolbar)
    (activity as AppCompatActivity).supportActionBar.apply {
        this?.setHomeButtonEnabled(true)
        this?.setDisplayHomeAsUpEnabled(true)
    }

}

Answer 2

我认为问题出在 NavigationUI.setupWithNavController() 函数上。

让我们看看下面的代码片段：

public static void setupWithNavController(@NonNull Toolbar toolbar,
        @NonNull final NavController navController,
        @NonNull final AppBarConfiguration configuration) {
    navController.addOnDestinationChangedListener(
            new ToolbarOnDestinationChangedListener(toolbar, configuration));
    toolbar.setNavigationOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            navigateUp(navController, configuration);
        }
    });
}

如我们所见，您正在向 navController 添加一个侦听器，它是 ToolbarOnDestinationChangedListener() 的一个新实例。

因为当 Activity/Fragment 生命周期进入 Destroy 状态时你没有移除 navController 的监听器，这很可能是你的问题所在。

Answer 3

我强烈建议在 onDestroy() 中取消设置（归零）片段中每个使用过的对象，尤其是位图：

@Override
public void onDestroy() {
    super.onDestroy();
    // Here is my example:
    myBigBitmap = null;
    adapter = new MyAdapter(requireContext(), new String[0], new String[0], new Bitmap[0]);
    listView.setAdapter(adapter);
    
}

这是唯一正确的方法。工作 100%。

Android导航UI组件内存泄漏

3 个答案: