flutter_native_drag_n_drop 1.2.1

A flutter plugin to support the native drag and drop.

example/lib/main.dart

import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_native_drag_n_drop/flutter_native_drag_n_drop.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  bool _dragging = false;
  AssetImage? _img;
  ByteData? _imageData;

  @override
  initState() {
    super.initState();

    rootBundle.load("assets/maldives.jpg").then((imgData) {
      setState(() {
        _imageData = imgData;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
          appBar: AppBar(
            title: const Text('Native drag & drop example'),
          ),
          body: Center(
              child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              NativeDropTarget(
                builder: ((context, candidateData, rejectedData) {
                  return Container(
                    height: 200,
                    width: 200,
                    color: _dragging ? Colors.blueAccent : Colors.grey,
                    child: _img != null
                        ? Image(height: 200, width: 200, image: _img!)
                        : const Center(child: Text("Drop Target")),
                  );
                }),
                onDragEntered: (details) {
                  setState(() {
                    _dragging = true;
                  });
                },
                onDragExited: (details) {
                  setState(() {
                    _dragging = false;
                  });
                },
                onDragDone: (details) {
                  AssetImage droppedImage =
                      details.items.first.data! as AssetImage;
                  setState(() {
                    _dragging = false;
                    _img = droppedImage;
                  });
                },
                onWillAccept: (details) {
                  return true;
                },
              ),
              const SizedBox(width: 15),
              NativeDraggable(
                child: const Image(
                    height: 200,
                    width: 200,
                    image: AssetImage("assets/maldives.jpg")),
                fileStreamCallback: passFileContent,
                fileItems: [
                  NativeDragFileItem(
                      fileName: "maldives.jpeg",
                      fileSize:
                          _imageData != null ? _imageData!.lengthInBytes : 0,
                      data: const AssetImage("assets/maldives.jpg"))
                ],
              ),
            ],
          ))),
    );
  }

  Stream<Uint8List> passFileContent(
      NativeDragItem<Object> item,
      String fileName,
      String url,
      ProgressController progressController) async* {
    final buffer = _imageData!.buffer.asUint8List();
    final range = buffer.length ~/ 10;

    for (var i = 0; i < 10; i++) {
      final startByte = i * range;
      final endByte = startByte + range;
      final sub = buffer.sublist(startByte, endByte);
      yield sub;
      progressController.updateProgress(endByte);
      await Future.delayed(const Duration(milliseconds: 500));
    }
    return;
  }
}