Flutter UI disappearing and appearing in Unity arcore scene

[GPavlioudakis]

I have a button over unity widget in ar scene and when I press it every flutter widgets disappears or blips.
I get this message on console:
W/ImageReader_JNI(15587): Unable to acquire a buffer item, very likely client tried to acquire more than maxImages buffers

[wanghuasheng]

我也遇到了，好像是flutter引擎的问题

[diybl]

我也遇到了，好像是flutter引擎的问题

解决了吗？？我也遇到。 稍微多一些 stack的ui就会出这种问题 还一闪一闪的。
感觉不太稳定。。

[cmd-dev]

I am getting the same exact issue, if I have 3 widgets on top then it works properly but If I add one more on top in the stack then every widget on top starts blinking @diybl @wanghuasheng

[vicmaurer]

Hi @cmd-dev were you able to solve the issue? I saw you were redirected to b5dd0d9 on #308 saying that reverting back to AndroidView instead of PlatformViewLink would solve the issue. I have tried useAndroidView=true with the latest version of the package (4.0.2) yet the Unity view does not even seem to initiate.

@juicycleff
While multiple individual widgets are drawn over the UnityWidget() in a Stack() the error and the blinking glitches happen for me the moment I either reopen the app after minimizing it (i.e. open native camera, switch to another app, etc...).

When commenting out the majority of the widgets in the stack the error does not occur and PlatformViewLink runs much smoother than AndroidView (which works in the version 2 of the package).

A similar bug I have seen on another thread that may or may not be related flutter/engine#24272

Phone : Huawei Mate 20 Pro
flutter 2.0.3 (but also tried with earlier versions)
unity 2019.4.3f1

edit: as a temporary workaround I made a ReloadUnityBloc.dart

import 'package:rxdart/rxdart.dart';


class ReloadUnityBloc {

  final BehaviorSubject<bool> _reloadUnity = BehaviorSubject<bool>();
  Stream<bool> get loading => _reloadUnity.stream;

  void triggerReload(){
    _reloadUnity.sink.add(true);
  }

  void endReload(){
    _reloadUnity.sink.add(false);
  }

  void dispose() {
    _reloadUnity.close();
  }
}

ReloadUnityBloc reloadUnityBloc = new ReloadUnityBloc();

Such that everytime I "resume" the app I call

void resumeUnity(){
  unityWidgetController.resume();
  reloadUnityBloc.triggerReload();
}

then I wrap UnityWidget into a StreamBuilder() that listens for "reload" trigger (if true, will render an empty Container() for one frame, then goes back to draw UnityWidget() afterwards).

StreamBuilder<bool>(
    stream: reloadUnityBloc.loading,
    builder: (context, AsyncSnapshot<bool> reloadUnity){
         if (!reloadUnity.hasData || reloadUnity.data == false)
             {
                   return 
                   UnityWidget(
                   onUnityCreated: onUnityCreated
                   onUnitySceneLoaded: onUnitySceneLoaded,
                   onUnityMessage: onUnityMessage,
              );
               }else{
                 reloadUnityBloc.endReload();
                 return Container();
               }
        }),

This gets rid of the repeated error and blinking, but introduces other bugs as sometimes reloading this way freezes the view and worst, in release, will give a black screen.

[dawiddszewczyk]

Hi this issue is outdated can you upgrade the unity flutter version, flutter version, and reimport the unity project with the new unity widget package.
If this issue still works please reopen issue or create new :)