CustomView中的DialogFragment导致内存泄漏

问题描述 投票：0回答：2

我有一个MainActivity，它的布局中有一个customView（DatePicker）。 DatePicker customView具有一个按钮和一个CustomDialogFragment。在DatePicker上单击Button时，将显示CustomDialogFragment。应用程序运行正常，但LeakCanary显示泄漏。这是代码（为简洁起见删除了一些代码）

MainActivity.class

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        date_picker.calendarDialog = getCalendarDialog()
    }

    private fun getCalendarDialog(): CalendarDialog {
        return CalendarDialog()
    }
}

activity_main.xml

  <androidx.constraintlayout.widget.ConstraintLayout>
    <com.example.testproject.customViews.DatePicker
        android:id="@+id/date_picker"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
    </com.example.testproject.customViews.DatePicker>
 </androidx.constraintlayout.widget.ConstraintLayout>

DatePicker.class

class DatePicker : FrameLayout {
    var calendarDialog: CalendarDialog? = null
    init {
        View.inflate(context, R.layout.date_picker, this)
        open_calendar.setOnClickListener {
            calendarDialog?.show((context as MainActivity).supportFragmentManager.beginTransaction(), "Calendar")
        }
    }
}

CalendarDialog.class

class CalendarDialog: DialogFragment() {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        val builder = AlertDialog.Builder(context!!)
        builder.setView(view)
            .setMessage("This is a dummy message")
            .setPositiveButton("OK") { dialog, which -> }
            .setNegativeButton("Cancel") { dialog, which -> }

        return builder.create()
    }
}

堆分析结果===================================1个应用程序泄漏

References underlined with "~~~" are likely causes.
Learn more at https://squ.re/leaks.

1437 bytes retained by leaking objects
Signature: 1eb8b5c7c3fd403a9a6851729c4044c8a6ce7cf6
┬───
│ GC Root: System class
│
├─ android.view.inputmethod.InputMethodManager class
│    Leaking: NO (InputMethodManager↓ is not leaking and a class is never leaking)
│    ↓ static InputMethodManager.sInstance
├─ android.view.inputmethod.InputMethodManager instance
│    Leaking: NO (DecorView↓ is not leaking and InputMethodManager is a singleton)
│    ↓ InputMethodManager.mNextServedView
├─ com.android.internal.policy.DecorView instance
│    Leaking: NO (LinearLayout↓ is not leaking and View attached)
│    mContext instance of com.android.internal.policy.DecorContext, wrapping activity com.example.testproject.MainActivity with mDestroyed = false
│    Parent android.view.ViewRootImpl not a android.view.View
│    View#mParent is set
│    View#mAttachInfo is not null (view attached)
│    View.mWindowAttachCount = 1
│    ↓ DecorView.mContentRoot
├─ android.widget.LinearLayout instance
│    Leaking: NO (MainActivity↓ is not leaking and View attached)
│    mContext instance of com.example.testproject.MainActivity with mDestroyed = false
│    View.parent com.android.internal.policy.DecorView attached as well
│    View#mParent is set
│    View#mAttachInfo is not null (view attached)
│    View.mWindowAttachCount = 1
│    ↓ LinearLayout.mContext
├─ com.example.testproject.MainActivity instance
│    Leaking: NO (DatePicker↓ is not leaking and Activity#mDestroyed is false)
│    ↓ MainActivity._$_findViewCache
├─ java.util.HashMap instance
│    Leaking: NO (DatePicker↓ is not leaking)
│    ↓ HashMap.table
├─ java.util.HashMap$Node[] array
│    Leaking: NO (DatePicker↓ is not leaking)
│    ↓ HashMap$Node[].[0]
├─ java.util.HashMap$Node instance
│    Leaking: NO (DatePicker↓ is not leaking)
│    ↓ HashMap$Node.value
├─ com.example.testproject.customViews.DatePicker instance
│    Leaking: NO (View attached)
│    mContext instance of com.example.testproject.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.date_picker
│    View.mWindowAttachCount = 1
│    ↓ DatePicker.calendarDialog
│                 ~~~~~~~~~~~~~~
╰→ com.example.testproject.customViews.CalendarDialog instance
​     Leaking: YES (ObjectWatcher was watching this because com.example.testproject.customViews.CalendarDialog received Fragment#onDestroy() callback and Fragment#mFragmentManager is null)
​     key = e176896c-49c6-4b17-a21e-4a6ca7cde260
​     watchDurationMillis = 11213
​     retainedDurationMillis = 6208
​     key = f3a2f22a-c77f-4c8e-a281-d803d110acff
​     watchDurationMillis = 11214
====================================
0 LIBRARY LEAKS

Library Leaks are leaks coming from the Android Framework or Google libraries.
====================================
METADATA

Please include this in bug reports and Stack Overflow questions.

Build.VERSION.SDK_INT: 28
Build.MANUFACTURER: Google
LeakCanary version: 2.2
App process name: com.example.testproject
Analysis duration: 4191 ms
Heap dump file path: /data/user/0/com.example.testproject/files/leakcanary/2020-03-11_10-15-46_729.hprof
Heap dump timestamp: 1583936152876
====================================

这些是我迄今为止没有尝试过的事情。

  1. 我曾尝试在其他地方初始化CalendarDialog。
  2. 在CalendarDialog类中创建一个侦听器，并在关闭对话框时将'calendarDialog'实例设为null。还有更多..
android memory-leaks android-dialogfragment leakcanary
2个回答
0
投票

关闭CalendarDialog片段后，该片段将被垃圾回收。但是，在这里我们可以看到DatePicker布局正在保留对其的引用，从而防止对其进行垃圾回收。 DatePicker仍附加，因此它仍然存在是有道理的，但是在关闭对话框时，应将其DatePicker.calendarDialog字段设置为null。

0
投票

您可以将CalendarDialog放入WeakReference中，这样就不必通过回调将其显式设置为null。垃圾收集器将自动清理它，您可以避免内存泄漏。

有关WeakReference的更多信息：https://developer.android.com/reference/java/lang/ref/WeakReference

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