Release build of example app

[stevegdavis]

Hello, has anyone successfully built the complete_example app in release mode, I can download the map but I only get a blank screen when displaying the map but all works in debug mode, however simple_example app works in both modes, Windows the same results. Thanks.

Typical error on Android:-
[2026-04-23 16:49:39.186 Uid(value=10382):32349:32349 E/flutter]
[ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: Invalid argument(s): Illegal argument in isolate message: object is unsendable - Library:'dart:async' Class: _AsyncCompleter@5048458 (see restrictions listed at SendPort.send() documentation for more information)
<- Instance of 'FlutterIsolateInstance' (from package:mapsforge_flutter_core/src/isolate/dart_isolate_io.dart)
<- Instance of 'IsolateMapfile' (from package:mapsforge_flutter_mapfile/src/mapfile.dart)
<- Instance of 'DatastoreReaderIsolateInitRequest' (from package:mapsforge_flutter_renderer/src/util/datastore_reader_impl.dart)
<- Instance of 'IsolateInitInstanceParams' (from package:mapsforge_flutter_core/src/isolate/dart_isolate_io.dart)

[mikes222]

When setting up an isolate, flutter serializes the objects and transfers them to the isolate (and back). Seems one of the objects have a property which is non-null and cannot be serialized. Typical examples are file system handles.

In your case we need to find out which object is affected. Seems something in mapfile but I am not sure. My suggestion is to strip down the setup as much as possible and find out when the problem disappears.

You could also try to create a simple example of your problem so that I can tackle the issue for you.

[stevegdavis]

@mikes222 thanks for the reply. I only get this problem if I fork/clone the repo. If I download the code from the latest tag (Version_4_0_0.zip) that builds and runs in both modes OK with no errors. Can see differences between the 2 code bases but I am not sure what to look for. Thanks.