Android/Java：TextInputEditText 在 Fragment 被破坏时泄漏

Question

我有一个Fragment，布局简单：
ConstraintLayout -> LinearLayout -> TextInputLayout -> TextInputEditText

它看起来不错并且可以工作，但是当我导航到另一个 Fragment 时，这意味着当前的 Fragment 被破坏，LeakCanary向我显示了一个意想不到的内存泄漏，与TextInputEditText 相关，即使我在onDestroyView() 中将其设置为null。

LeakCanary 报告：

ConstraintLayout leaked
-> InputMethodManager$ControlledInputConnectionWrapper.mInputConnection
-> EditableInputConnection.mTextView
-> TextInputEditText.mParent

MyFragment.java

public class MyFragment extends Fragment {
    private View view;
    private EditText et;

    public MyFragment() {}

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.my_layout, container, false);
        et   = view.findViewById(R.id.my_et);
        return view;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();

        et    = null;
        view  = null;

        // No difference, if I  call super.onDestroyView(); here
    }
}

my_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/my_cl"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:gravity="center_horizontal"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <android.support.design.widget.TextInputLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/my_et"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Password"
                android:inputType="numberPassword" />   
        </android.support.design.widget.TextInputLayout>   
    </LinearLayout>    
</android.support.constraint.ConstraintLayout>

有什么想法吗？提前致谢！

编辑 1
当我从布局中删除 android.support.design.widget.TextInputEditText 时，泄漏不会出现。

Answer 1

这不是一个解决方案，但可能会引导您找到一个解决方案。

由于您使用的是 LeakCanary，请检查他们的 AndroidExcludedRefs.java 文件，该文件包含 Android SDK 本身或某些制造商版本中的已知泄漏列表。

它包含几个已知的 InputMethodManager 泄漏，其中一个可能是您看到的泄漏的原因。两者都包含指向可能解决方法的“Hack”链接。

  INPUT_METHOD_MANAGER__SERVED_VIEW(SDK_INT >= ICE_CREAM_SANDWICH_MR1 && SDK_INT <= N_MR1) {
    @Override void add(ExcludedRefs.Builder excluded) {
      String reason = "When we detach a view that receives keyboard input, the InputMethodManager"
          + " leaks a reference to it until a new view asks for keyboard input."
          + " Tracked here: https://code.google.com/p/android/issues/detail?id=171190"
          + " Hack: https://gist.github.com/pyricau/4df64341cc978a7de414";
      excluded.instanceField("android.view.inputmethod.InputMethodManager", "mNextServedView")
          .reason(reason);
      excluded.instanceField("android.view.inputmethod.InputMethodManager", "mServedView")
          .reason(reason);
      excluded.instanceField("android.view.inputmethod.InputMethodManager",
          "mServedInputConnection").reason(reason);
    }
  },

  INPUT_METHOD_MANAGER__ROOT_VIEW(SDK_INT >= ICE_CREAM_SANDWICH_MR1 && SDK_INT <= M) {
    @Override void add(ExcludedRefs.Builder excluded) {
      excluded.instanceField("android.view.inputmethod.InputMethodManager", "mCurRootView")
          .reason("The singleton InputMethodManager is holding a reference to mCurRootView long"
              + " after the activity has been destroyed."
              + " Observed on ICS MR1: https://github.com/square/leakcanary/issues/1"
              + "#issuecomment-100579429"
              + " Hack: https://gist.github.com/pyricau/4df64341cc978a7de414");
    }
  },