Cant relaunch unity widget after went to background

[virtyos]

After my app was gone to background and launched again unity widget had stopped to render

Getting this error in logs

2022-07-25 05:49:06.191 13751-13845/? W/OpenGLRenderer: Surface doesn't have any previously queued frames, nothing to readback from
2022-07-25 05:49:06.209 13751-13751/? D/FlutterUnityController: onDestroy
2022-07-25 05:49:06.209 13751-13751/? D/FlutterUnityController: onDestroy
2022-07-25 05:49:06.212 13751-13751/? I/CustomUnityPlayer: onDetachedFromWindow
2022-07-25 05:49:06.216 13751-13751/? W/FlutterSurfaceView: detachFromRenderer() invoked when no FlutterRenderer was attached.
2022-07-25 05:49:06.217 13751-13751/? D/FUWPlugin: onDetachedFromActivity
2022-07-25 05:49:06.218 13751-13751/? D/FUWPlugin: handleActivityChange
2022-07-25 05:49:06.220 13751-13751/? E/UnityPlayerUtils: An operation is not implemented: Not yet implemented
2022-07-25 05:49:06.220 13751-13751/? D/FUWPlugin: onDetachedFromEngine
2022-07-25 05:49:06.221 13751-13751/? D/FlutterUnityController: this controller disposed
2022-07-25 05:49:06.221 13751-13751/? D/FlutterUnityController: Attaching unity to view
2022-07-25 05:49:06.228 13751-13751/? E/PlatformViewsController: Disposing platform view threw an exception
    java.lang.NullPointerException
        at com.xraph.plugin.flutter_unity_widget.FlutterUnityWidgetPlugin$onAttachedToEngine$1.getLifecycle(FlutterUnityWidgetPlugin.kt:35)
        at com.xraph.plugin.flutter_unity_widget.FlutterUnityWidgetController.dispose(FlutterUnityWidgetController.kt:101)
        at io.flutter.plugin.platform.PlatformViewsController$1.dispose(PlatformViewsController.java:376)
        at io.flutter.plugin.platform.PlatformViewsController.diposeAllViews(PlatformViewsController.java:968)
        at io.flutter.plugin.platform.PlatformViewsController.onDetachedFromJNI(PlatformViewsController.java:860)
        at io.flutter.embedding.engine.FlutterEngine.destroy(FlutterEngine.java:428)
        at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onDetach(FlutterActivityAndFragmentDelegate.java:708)
        at io.flutter.embedding.android.FlutterActivity.onDestroy(FlutterActivity.java:715)
        at android.app.Activity.performDestroy(Activity.java:8625)
        at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1364)
        at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:5706)
        at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:5752)
        at android.app.servertransaction.DestroyActivityItem.execute(DestroyActivityItem.java:47)
        at android.app.servertransaction.ActivityTransactionItem.execute(ActivityTransactionItem.java:45)
        at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2423)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loopOnce(Looper.java:233)
        at android.os.Looper.loop(Looper.java:334)
        at android.app.ActivityThread.main(ActivityThread.java:8333)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:582)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1065)
2022-07-25 05:49:06.241 13751-13857/? E/libEGL: call to OpenGL ES API with no current context (logged once per thread)
2022-07-25 05:49:06.262 13751-13751/? W/FlutterJNI: Tried to send a platform message to Flutter, but FlutterJNI was detached from native C++. Could not send. Channel: plugin.xraph.com/unity_view_0. Response ID: 10
2022-07-25 05:49:07.406 13751-13751/? D/FUWPlugin: onAttachedToEngine
2022-07-25 05:49:07.406 13751-13751/? D/FUWPlugin: onAttachedToActivity
2022-07-25 05:49:07.406 13751-13751/? D/FUWPlugin: handleActivityChange

android 11, flutter 3.0.5, unity 2022, fuw-2022.1.7f1.unitypackage

[Ahmadre]

Did you try:

@override
void didChangeAppLifecycleState(AppLifecycleState state) {
  switch (state) {
    case AppLifecycleState.resumed:
      unityWidgetController.resume();
      break;
    case AppLifecycleState.paused:
      unityWidgetController.pause();
      break;
    default:
  }
}

For more read Flutter's: WidgetsBindingObserver

[virtyos]

@Ahmadre not working, result is the same.

my logs while running:

I/flutter (31765): STATE AppLifecycleState.inactive
I/flutter (31765): STATE AppLifecycleState.paused
D/FlutterUnityController(31765): onDestroy
D/FlutterUnityController(31765): onDestroy
D/FlutterUnityController(31765): onDestroy
I/CustomUnityPlayer(31765): onDetachedFromWindow
W/FlutterSurfaceView(31765): detachFromRenderer() invoked when no FlutterRenderer was attached.
D/FUWPlugin(31765): onDetachedFromActivity
D/FUWPlugin(31765): handleActivityChange
W/MessageQueue(31765): Handler (android.os.Handler) {e1928f9} sending message to a Handler on a dead thread
W/MessageQueue(31765): java.lang.IllegalStateException: Handler (android.os.Handler) {e1928f9} sending message to a Handler on a dead thread
W/MessageQueue(31765): 	at android.os.MessageQueue.enqueueMessage(MessageQueue.java:564)
W/MessageQueue(31765): 	at android.os.Handler.enqueueMessage(Handler.java:778)
W/MessageQueue(31765): 	at android.os.Handler.sendMessageAtTime(Handler.java:727)
W/MessageQueue(31765): 	at android.os.Handler.sendMessageDelayed(Handler.java:697)
W/MessageQueue(31765): 	at android.os.Handler.sendMessage(Handler.java:635)
W/MessageQueue(31765): 	at android.os.Message.sendToTarget(Message.java:471)
W/MessageQueue(31765): 	at com.unity3d.player.UnityPlayer$e.a(Unknown Source:10)
W/MessageQueue(31765): 	at com.unity3d.player.UnityPlayer$e.a(Unknown Source:2)
W/MessageQueue(31765): 	at com.unity3d.player.UnityPlayer.destroy(Unknown Source:53)
W/MessageQueue(31765): 	at com.unity3d.player.UnityPlayer.quit(Unknown Source:0)
W/MessageQueue(31765): 	at com.xraph.plugin.flutter_unity_widget.UnityPlayerUtils$Companion.quitPlayer(UnityPlayerUtils.kt:124)
W/MessageQueue(31765): 	at com.xraph.plugin.flutter_unity_widget.FlutterUnityWidgetPlugin.handleActivityChange(FlutterUnityWidgetPlugin.kt:86)
W/MessageQueue(31765): 	at com.xraph.plugin.flutter_unity_widget.FlutterUnityWidgetPlugin.onDetachedFromActivity(FlutterUnityWidgetPlugin.kt:69)
W/MessageQueue(31765): 	at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.detachFromActivity(FlutterEngineConnectionRegistry.java:383)
W/MessageQueue(31765): 	at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onDetach(FlutterActivityAndFragmentDelegate.java:690)
W/MessageQueue(31765): 	at io.flutter.embedding.android.FlutterActivity.onDestroy(FlutterActivity.java:715)
W/MessageQueue(31765): 	at android.app.Activity.performDestroy(Activity.java:8625)
W/MessageQueue(31765): 	at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1364)
W/MessageQueue(31765): 	at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:5706)
W/MessageQueue(31765): 	at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:5752)
W/MessageQueue(31765): 	at android.app.servertransaction.DestroyActivityItem.execute(DestroyActivityItem.java:47)
W/MessageQueue(31765): 	at android.app.servertransaction.ActivityTransactionItem.execute(ActivityTransactionItem.java:45)
W/MessageQueue(31765): 	at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
W/MessageQueue(31765): 	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
W/MessageQueue(31765): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2423)
W/MessageQueue(31765): 	at android.os.Handler.dispatchMessage(Handler.java:106)
W/MessageQueue(31765): 	at android.os.Looper.loopOnce(Looper.java:233)
W/MessageQueue(31765): 	at android.os.Looper.loop(Looper.java:334)
W/MessageQueue(31765): 	at android.app.ActivityThread.main(ActivityThread.java:8333)
W/MessageQueue(31765): 	at java.lang.reflect.Method.invoke(Native Method)
W/MessageQueue(31765): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:582)
W/MessageQueue(31765): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1065)
E/UnityPlayerUtils(31765): An operation is not implemented: Not yet implemented
D/FUWPlugin(31765): onDetachedFromEngine
I/flutter (31765): STATE AppLifecycleState.detached
D/FlutterUnityController(31765): this controller disposed
D/FlutterUnityController(31765): Attaching unity to view
E/PlatformViewsController(31765): Disposing platform view threw an exception
E/PlatformViewsController(31765): java.lang.NullPointerException
E/PlatformViewsController(31765): 	at com.xraph.plugin.flutter_unity_widget.FlutterUnityWidgetPlugin$onAttachedToEngine$1.getLifecycle(FlutterUnityWidgetPlugin.kt:35)
E/PlatformViewsController(31765): 	at com.xraph.plugin.flutter_unity_widget.FlutterUnityWidgetController.dispose(FlutterUnityWidgetController.kt:101)
E/PlatformViewsController(31765): 	at io.flutter.plugin.platform.PlatformViewsController$1.dispose(PlatformViewsController.java:376)
E/PlatformViewsController(31765): 	at io.flutter.plugin.platform.PlatformViewsController.diposeAllViews(PlatformViewsController.java:968)
E/PlatformViewsController(31765): 	at io.flutter.plugin.platform.PlatformViewsController.onDetachedFromJNI(PlatformViewsController.java:860)
E/PlatformViewsController(31765): 	at io.flutter.embedding.engine.FlutterEngine.destroy(FlutterEngine.java:428)
E/PlatformViewsController(31765): 	at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onDetach(FlutterActivityAndFragmentDelegate.java:708)
E/PlatformViewsController(31765): 	at io.flutter.embedding.android.FlutterActivity.onDestroy(FlutterActivity.java:715)
E/PlatformViewsController(31765): 	at android.app.Activity.performDestroy(Activity.java:8625)
E/PlatformViewsController(31765): 	at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1364)
E/PlatformViewsController(31765): 	at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:5706)
E/PlatformViewsController(31765): 	at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:5752)
E/PlatformViewsController(31765): 	at android.app.servertransaction.DestroyActivityItem.execute(DestroyActivityItem.java:47)
E/PlatformViewsController(31765): 	at android.app.servertransaction.ActivityTransactionItem.execute(ActivityTransactionItem.java:45)
E/PlatformViewsController(31765): 	at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
E/PlatformViewsController(31765): 	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
E/PlatformViewsController(31765): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2423)
E/PlatformViewsController(31765): 	at android.os.Handler.dispatchMessage(Handler.java:106)
E/PlatformViewsController(31765): 	at android.os.Looper.loopOnce(Looper.java:233)
E/PlatformViewsController(31765): 	at android.os.Looper.loop(Looper.java:334)
E/PlatformViewsController(31765): 	at android.app.ActivityThread.main(ActivityThread.java:8333)
E/PlatformViewsController(31765): 	at java.lang.reflect.Method.invoke(Native Method)
E/PlatformViewsController(31765): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:582)
E/PlatformViewsController(31765): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1065)
W/FlutterJNI(31765): Tried to send a platform message response, but FlutterJNI was detached from native C++. Could not send. Response ID: 30
W/FlutterJNI(31765): Tried to send a platform message to Flutter, but FlutterJNI was detached from native C++. Could not send. Channel: plugin.xraph.com/unity_view_0. Response ID: 11

[virtyos]

the issue takes place when the app goes to backgroud after pushing back button. As I understand we need to catch onDestroy event? But I dont know how.

[virtyos]

Actually the problem is that it's imp[ossible to recreate unity widget (or controller?) after calling ondestroy

D/FlutterUnityController(23019): onDestroy
D/FlutterUnityController(23019): onDestroy

[virtyos]

any updates?

[dawiddszewczyk]

Hi @virtyos, Can you show yours flutter UnityWidget code? Its seems you close player after calls onDestroy then its no possible to recreate playerAgain. Because unityplayer need to works in background.

[swkim-lbstech]

I'm having the same problem.

https://user-images.githubusercontent.com/72723485/231081303-88bc60dc-5799-4fbf-9489-1dfdbd3e2399.mp4