How to receive both onTapDown (eagerly) and onDoubleTap? - flutter

Question

I'd like to perform some interaction:
when an initial touch (onTapDown) happens (e.g. clear existing selections), AND
when a double tap happens (onDoubleTap) happens (e.g. highlight a new selection)
Using a GestureDetector:
if only register a onTapDown, the callback is called immediately at the first touch
if I register both onTapDown and onDoubleTap, and the user performs a simple tap, it takes some considerable time until the onTapDown event is called (1/2 a second?). If I update the display following the tap, for the user, this feels like rendering jank -- but it in fact just getting the event to late.
Is there a way to eagerly receive onTapDown AND onDoubleTap? (Its OK, in fact preferred, if I get 2 events on a double tap).
import 'package:flutter/material.dart';
// 1. double tap the green box
// 2. single tap the green box again and that it takes a long
// time to update the text
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) => MaterialApp(
title: 'Flutter Playground',
home: Material(child: SafeArea(child: content())));
Widget content() {
final controller = TextEditingController(text: "-");
return Center(
child: Column(children: [
GestureDetector(
onTapDown: (_) {
controller.text = "tap down";
// print("[${DateTime.now().millisecondsSinceEpoch}] tap down");
},
onDoubleTap: () {
controller.text = "double tap ";
// print("[${DateTime.now().millisecondsSinceEpoch}] double tap");
},
child: Container(
color: Colors.green,
width: 200,
height: 200,
child: Center(child: Text("Tap me")))),
Container(
color: Colors.red,
width: 200,
height: 200,
child: Center(child: TextField(controller: controller)))
]));
}
}
main() => runApp(MyApp());

Answer 1

A hacky way to do it I suppose, but you can use a Listener for onPointerDown. The code below should log tap down twice when you double-tap:
import 'package:flutter/material.dart';
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) => MaterialApp(title: 'Flutter Playground', home: Material(child: SafeArea(child: content())));
Widget content() {
final controller = TextEditingController(text: "-");
return Center(
child: Column(
children: [
GestureDetector(
onDoubleTap: () {
controller.text = "double tap";
print("double tap");
},
child: Listener(
onPointerDown: (_) {
controller.text = "tap down";
print("tap down");
},
child: Container(
color: Colors.green,
width: 200,
height: 200,
child: Center(
child: Text("Tap me"),
),
),
)),
Container(
color: Colors.red,
width: 200,
height: 200,
child: Center(
child: TextField(controller: controller),
),
)
],
),
);
}
}
main() => runApp(MyApp());

Answer 2

Use gesture_x_detector plugin.
XGestureDetector(
bypassTapEventOnDoubleTap: true,
doubleTapTimeConsider: 170
child: ...
)