Passing the controller as a parameter and update it's value

[asadamatic]

Hi there,

I'm working on a package that allows users to pick files and show a list of selected files in a widget. I want that user should be able to access those files in the widget that File widget that my package provides.

The flow of package usage,

1. Create an instance of the controller case name 'FileController`.

final _firstController = FileController();

2. Add a File widget and a corresponding 'FileUploadIconButtonto you're widget tree and pass this controller toFile and 'FileUploadIconButtonwidget.

class Home extends StatelessWidget {
  Home({Key? key}) : super(key: key);

  final _firstController = FileController();
  final _secondController = FileController();
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Center(
            child: Column(
      children: [
        FileHolder(
          controller: _firstController,
          tag: 'controller1',
        ),
        FileUploadIconButton(controller: _firstController, tag: 'controller1'),
        FileHolder(controller: _secondController, tag: 'controller2'),
        FileUploadIconButton(controller: _secondController, tag: 'controller2'),
        TextButton(
            onPressed: () {
              print(_firstController.files.length);
            },
            child: Text('Press me '))
      ],
    )));
  }
}

I'm using the tag to differentiate between multiple instances of the controller.

The code for File widget.

class FileHolder extends StatelessWidget {
  FileController? _fileController;
  FileHolder({Key? key, this.controller, this.tag}) : super(key: key) {
    _fileController = Get.put(controller!, tag: tag);
  }
  final FileController? controller;
  final String? tag;
  @override
  Widget build(BuildContext context) {

    return Obx(() {

      print(_fileController!.files.length);
      if (_fileController!.files.isEmpty) {
        return const Padding(padding: EdgeInsets.all(24.0));
      }
      return Container(
        height: 100.0,
        decoration: BoxDecoration(
          color: Theme.of(context).primaryColor,
          borderRadius: BorderRadius.circular(8.0),
          boxShadow: [
            BoxShadow(
              color: Theme.of(context).primaryColor.withOpacity(0.3),
              spreadRadius: 5,
              blurRadius: 7,
              offset: const Offset(0, 3), // changes position of shadow
            ),
          ],
        ),
        margin: const EdgeInsets.all(12.0),
        padding: const EdgeInsets.symmetric(horizontal: 24.0, vertical: 14.0),
        child: ListView.builder(
          shrinkWrap: true,
          scrollDirection: Axis.horizontal,
          itemCount: _fileController!.files.length + 1,
          itemBuilder: (_, index) => index == _fileController!.files.length
              ? IconButton(
                  onPressed: _fileController!.addFile,
                  icon: const Icon(Icons.add),
                  color: Colors.white,
                )
              : FileIcon(
                  fileName: _fileController!.files[index].name,
                  index: index,
                  tag: tag,
                ),
        ),
      );
    });
}

Code for 'FileUploadIconButton`

class FileUploadIconButton extends StatelessWidget {
  FileController? _fileController;
  FileUploadIconButton({Key? key, this.controller, this.tag})
      : super(key: key) {
    _fileController = Get.find(tag: tag);
  }
  final FileController? controller;
  final String? tag;

  @override
  Widget build(BuildContext context) {
    return IconButton(
      onPressed: () {
        _fileController!.pickFiles();
      },
      icon: const Icon(Icons.upload_file),
      padding: const EdgeInsets.symmetric(horizontal: 18.0, vertical: 16.0),
    );
  }
}

The file selection is working well and the two instances are separated as required.

Requirement

I want to use the controllers initiated inside the Home widget and passed to the package widgets and access the selected files, and currently, the _firstController.files in the Home is empty because it is not updated like the Obx widget inside the FileHolder widget. Since the user should be able to use the FileHolder widget without having to use the Get package, so please help me figure out a way to update the controller that was passed from outside the package.