bytebeats/robustdialogfragment

A DialogFragment who has no concerns about IllegalStateException, Memory Leaks and IllegalArgumentException.

RobustDialogFragment: DialogFragment can be robust

DialogFragment works great with Dialog and Fragment.
But DialogFragment is not always working stable. Scenes like:

• Try to show DialogFragment when Activity or Fragment has been destroyed or state-saved, which will throws IllegalStateException, like
  • Can not perform this action after onSaveInstanceState.
  • fragment {xxx} not associated with a fragment manager.
• DialogFragment can't work well with in-layout Fragments, which cause IllegalArgumentException, like
  • Binary XML file line #30: Duplicate id 0x7f080047.
• Sometimes DialogFragment cause memory leaks.

For how official DialogFragment leaks memory, As we know,
official DialogFragment works with Activity/Fragment through FragmentManager.
There is mDialog in DialogFragment which implements DialogInterface.OnDismissListener and mDialog.setOnDismissListener(this) where this is current DialogFragment.
In Dialog#setOnDismissListener(listener), Dialog#mDismissMessage = mListenersHandler.obtainMessage(DISMISS, listener), so Dialog#mDismissMessage#obj is listener, namely current DialogFragment.
So, a Message referred DialogFragment, which referred Activity/Fragment through FragmentManager.
Meantime, in Looper#loop(), there is Message msg = queue.next(), which will block current Thread when no messages in MessageQueue.
When MessageQueue has no messages, queue.next() block current Thread while local variable msg has been allocated.
DialogFragment instance referred by msg won't be gc, and therefore Activity/Fragment won't be gc.
So Memory leaks happen.

So, my solution is: When Dialog#setOnDismissListener(listener), the listener holds DialogFragment instance by WeakReference. So, when MessageQueue blocks, local variable msg won't hold DialogFragment instance. Memory won't leak by MessageQueue#next()#msg or Activity/Fragment.

Stargazers over time

MIT License

Copyright (c) 2021 Chen Pan

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.