draggable_dough.dart

import 'package:dough/dough.dart';
import 'package:flutter/material.dart';

class DraggableDoughDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // This is the widget that appears before being dragged around.
    final myDraggableChild = Container(
      width: 100,
      height: 100,
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(20),
        color: Colors.blue,
      ),
      child: Center(
        child: Text(
          'Draggable',
          textAlign: TextAlign.center,
          style: Theme.of(context).accentTextTheme.bodyText2,
        ),
      ),
    );

    // This is the widget that gets dragged around.
    final myFeedbackWidget = Container(
      width: 100,
      height: 100,
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(20),
        color: Colors.green,
      ),
      child: Center(
        child: Text(
          'Drag Me ',
          textAlign: TextAlign.center,
          style: Theme.of(context).accentTextTheme.bodyText2,
        ),
      ),
    );

    myDraggableDough() => DoughRecipe(
          data: DoughRecipeData(
            adhesion: 4,
            viscosity: 500,
            draggablePrefs: DraggableDoughPrefs(
              breakDistance: 80,
              useHapticsOnBreak: true,
            ),
          ),
          child: DraggableDough<String>(
            data: 'My data!',
            child: myDraggableChild,
            feedback: myFeedbackWidget,
            onDoughBreak: () {},
          ),
        );

    myDragTarget() => DragTarget<String>(
          builder: (context, candidateData, rejectedData) {
            return Container(
              height: 100,
              width: 100,
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(20),
                color:
                    candidateData.length > 0 ? Colors.lightGreen : Colors.grey,
              ),
              child: Center(
                child: Text(
                  'Drag target',
                  textAlign: TextAlign.center,
                  style: Theme.of(context).accentTextTheme.bodyText2,
                ),
              ),
            );
          },
          onWillAccept: (value) => value == 'My data!',
          onAccept: (value) {},
        );

    return Scaffold(
      appBar: AppBar(
        title: Text('Draggable Dough'),
      ),
      body: Stack(
        children: [
          Positioned(
            left: 50,
            top: 50,
            child: myDraggableDough(),
          ),
          Positioned(
            right: 50,
            bottom: 50,
            child: myDragTarget(),
          ),
        ],
      ),
    );
  }
}