main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Support Example',

      home: MyHomePage(title: 'Support Example'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  PointerDownEvent lastPointerDownEvent;
  DragUpdateDetails lastDragUpdateDetails;

  @override
  Widget build(BuildContext context) {

    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Listener(
        onPointerDown: (PointerDownEvent event) {
          setState(() {
            this.lastPointerDownEvent = event;
            print('lastPointerDownEvent: ${lastPointerDownEvent}');
          });
        },

        child: GestureDetector(
          onPanUpdate: (DragUpdateDetails details) {
            setState(() {
              this.lastDragUpdateDetails = details;
            });
          },

          child: Column (
            children: <Widget>[
              Expanded(
                child: Container(
                  child: Text('lastPointerDownEvent: ${lastPointerDownEvent} \n\n lastDragUpdateDetails: $lastDragUpdateDetails'),
                  color: Colors.red[200],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}