H5_Flutter/lib/view/component/upload_file.dart

import 'dart:async';
import 'dart:html';
import 'dart:typed_data';
import 'dart:ui' as ui;
import 'package:flutter/cupertino.dart';

class UploadFile extends StatefulWidget {
  // double width, height;
  Widget child;
  var callback;
  UploadFile(
      {Key? key,
      // required this.width,
      // required this.height,
      required this.child,
      required this.callback})
      : super(key: key);

  @override
  State<UploadFile> createState() => UploadFileState();
}

class UploadFileState extends State<UploadFile> {

  // InputElement input = InputElement(type: '');
  FileUploadInputElement uploadInput = FileUploadInputElement();

  @override
  void initState() {
    // TODO: implement initState

    Timer(const Duration(seconds: 1), () {
      // uploadInput.click();
      chooseFile();
    });
    super.initState();
  }

  chooseFile() async {
    uploadInput.accept = '.png,.jpg,.jpeg';
    uploadInput.multiple = false;
    // uploadInput.click();
    uploadInput.onChange.listen((e) {
      final files = uploadInput.files;
      if (files?.length == 1) {
        FileReader reader = FileReader();
        reader.onLoadEnd.listen((event) {
          setState(() {
            widget.callback(reader.result as Uint8List);
            // chooseImage = reader.result as Uint8List;
          });
        });
        reader.readAsArrayBuffer(files![0]);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    String _divId = "file_" + DateTime.now().toIso8601String();
    ui.platformViewRegistry.registerViewFactory(
        _divId,
        (int viewId) => uploadInput
          ..style.width = '100%'
          ..style.height = '100%'
          ..style.opacity = '0.0');
    return Stack(
        children: [
          widget.child,
          Positioned(
            left: 0,right: 0,top: 0,bottom: 0
            ,child: HtmlElementView(
              key: UniqueKey(),
              viewType: _divId,
            ))
          // SizedBox(
          //   width: widget.width,
          //   height: widget.height,
          //   child: HtmlElementView(
          //     key: UniqueKey(),
          //     viewType: _divId,
          //   ),
          // )
          // SizedBox()
        ],
    );
  }
}