Integration in a flutter project

The integration with flutter can be done by using a native view controller that you'll present over the flutter view controller.

It means you'll have to customize it in the native part.

Here are the steps :

1. Create a communication channel for flutter to communicate with the app. Examples are easy to find. Here is the official documentation : https://flutter.dev/docs/development/platform-integration/platform-channels

2. In the native part you can copy code of the sample. Copy the full scanner class and the storyboard related view controller into your project.

3. Modify the declaration of the class to add

//import the module
@import Flutter;  
//add strong reference to store the callback block
@property (strong,nonatomic)FlutterResult result; 

4. In your app delegate you'll need to display this view controller when the method is called

        if ([call.method isEqualToString:@"scanItem"])
        {
            //create the VC
            FLUScanVC* scvc = [[UIStoryboard storyboardWithName:@"Main"  bundle:nil] instantiateViewControllerWithIdentifier:@"FLUScanVC"];
            //assign the result block
            scvc.result = result; 
            //Display the VC
            [controller presentViewController:scvc animated:YES completion:nil];
        }
        else
        {
            result(FlutterMethodNotImplemented);
        }

5. To return something when the scanner found a code you can just add a few line in the scanner view controller's SmartScannerFoundCode method

        //call the result block with the code 
        self->_result(aCode);
        //Dismisse the scanner VC
        [self dismissViewControllerAnimated:YES completion:nil];