Issue

I am developing an app with Flutter that takes an image and allows the user to save it in the gallery.

I am using image_picker_saver plugin to save it.

In the beginning I was calling the method to save the image in the main thread but I realized that was really slow and now I am trying to put it in a new isolated thread, but I am getting the same error all the time, so, my question is: How can I call the method to save the image in a new isolated thread?

My code looks like this:

Main.dart

    class _AkkaMark extends State<CameraUpload>{
    .
    .
    .
        void _clickSaveImage() {
          compute(saveImage, _imageFile).then((Future<String> futurePath) {
              futurePath.then((String path){
                _imageFile = new File(path);
              });
          });
        }
    .
    .
    .
    }

toCompute.dart

    Future<String> saveImage(File image) async {

      return await ImagePickerSaver.saveFile(fileData: image.readAsBytesSync());

    }

I tried to change the code trying to locate the error but is always the same:

    E/flutter (22602): [ERROR:flutter/runtime/dart_isolate.cc(717)] Isolate (413787440) 'main.dart:_spawn()' exited with an error
    E/flutter (22602): [ERROR:flutter/shell/common/shell.cc(184)] Dart Error: Unhandled exception:
    E/flutter (22602): error: native function 'Window_sendPlatformMessage' (4 arguments) cannot be found
    E/flutter (22602): #0      Window.sendPlatformMessage (dart:ui/window.dart:811:9)
    E/flutter (22602): #1      BinaryMessages._sendPlatformMessage (package:flutter/src/services/platform_messages.dart:40:15)
    E/flutter (22602): #2      BinaryMessages.send (package:flutter/src/services/platform_messages.dart:88:12)
    E/flutter (22602): #3      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:286:49)
    E/flutter (22602): <asynchronous suspension>
    E/flutter (22602): #4      ImagePickerSaver.saveFile (package:image_picker_saver/image_picker_saver.dart:77:38)
    E/flutter (22602): <asynchronous suspension>
    E/flutter (22602): #5      saveImage (package:AKKAmark/toCompute.dart:113:35)
    E/flutter (22602): <asynchronous suspension>
    E/flutter (22602): #6      _IsolateConfiguration.apply (package:flutter/src/foundation/isolates.dart:88:16)
    E/flutter (22602): #7      _spawn.<anonymous closure> (package:flutter/src/foundation/isolates.dart:96:30)
    E/flutter (22602): #8      Timeline.timeSync (dart:developer/timeline.dart:168:22)
    E/flutter (22602): #9      _spawn (package:flutter/src/foundation/isolates.dart:93:12)
    E/flutter (22602): #10     _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:292:17)
    E/flutter (22602): #11     _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)

Someone has any clue? Thanks in advance

Edit

I put the question on GitHub and basically plugins only can be used in the main UI thread.

‘Window_sendPlatformMessage’ (4 arguments) cannot be found

Solution

I put the question on GitHub and basically plugins only can be used in the main UI thread.

‘Window_sendPlatformMessage’ (4 arguments) cannot be found

Answered By – Nadia Ghebreial

Answer Checked By – Gilberto Lyons (FlutterFixes Admin)