Почему мой пользовательский ScrollPhysics из Flutter ломает GestureDetectors в моем Scrollable? Я использую SingleChildScrollView, который использует пользовательский ScrollPhysics, который я написал, и по какой-то причине те элементы GestureDetectors, которые есть в ScrollView, вообще не реагируют на прикосновения, ЕСЛИ БЕЗ ScrollView не перепрограммирован.
По сути, если я только что недавно прокрутил до экстента прокрутки и ScrollView не остановился на экстенте прокрутки, я не могу обнаружить какие-либо жесты в пользовательском физическом ScrollView. Конечно, обнаружение жестов внутри обычного ScrollView работает нормально.
Вот видео моего затруднительного положения; синий ScrollView слева использует ScrollPhysics по умолчанию, а янтарный справа использует мой пользовательский ScrollPhysics с пятью накладными полями в каждом ScrollView:
Вот GitHub:
А вот и сам код:
import 'package:flutter/material.dart';
import 'package:flutter/physics.dart';
import 'package:flutter/widgets.dart';
import 'dart:math' as math;
void main() {
runApp(FlutterSingleChildScrollViewAbsorbsGesturesExample());
}
class FlutterSingleChildScrollViewAbsorbsGesturesExample extends StatefulWidget {
@override
State<FlutterSingleChildScrollViewAbsorbsGesturesExample> createState() =>
FlutterSingleChildScrollViewAbsorbsGesturesExampleState();
}
class FlutterSingleChildScrollViewAbsorbsGesturesExampleState
extends State<FlutterSingleChildScrollViewAbsorbsGesturesExample> {
Color colorOfRegularPhysicsBoxOne = Colors.black;
Color colorOfRegularPhysicsBoxTwo = Colors.black;
Color colorOfRegularPhysicsBoxThree = Colors.black;
Color colorOfRegularPhysicsBoxFour = Colors.black;
Color colorOfRegularPhysicsBoxFive = Colors.black;
Color colorOfCustomPhysicsBoxOne = Colors.black;
Color colorOfCustomPhysicsBoxTwo = Colors.black;
Color colorOfCustomPhysicsBoxThree = Colors.black;
Color colorOfCustomPhysicsBoxFour = Colors.black;
Color colorOfCustomPhysicsBoxFive = Colors.black;
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'An example of how the SingleChildScrollView with custom ScrollPhysics looks like it is eating gestures '
'meant for its descendants',
home: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
SingleChildScrollView(
child: Container(
height: 1400.0,
width: 200.0,
color: Colors.lightBlue,
child: Center(
child: Column(
children: <Widget>[
GestureDetector(
onTap: () => setState(() {
colorOfRegularPhysicsBoxOne = Colors.white;
}),
child: Container(
color: colorOfRegularPhysicsBoxOne,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfRegularPhysicsBoxTwo = Colors.white;
}),
child: Container(
color: colorOfRegularPhysicsBoxTwo,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfRegularPhysicsBoxThree = Colors.white;
}),
child: Container(
color: colorOfRegularPhysicsBoxThree,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfRegularPhysicsBoxFour = Colors.white;
}),
child: Container(
color: colorOfRegularPhysicsBoxFour,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfRegularPhysicsBoxFive = Colors.white;
}),
child: Container(
color: colorOfRegularPhysicsBoxFive,
height: 100.0,
width: 100.0,
),
),
],
),
),
),
),
SingleChildScrollView(
physics: CustomSnappingScrollPhysicsForTheControlPanelHousing(stoppingPoints: [
0.0,
100.0,
200.0,
300.0,
400.0,
]),
child: Container(
height: 1400.0,
width: 200.0,
color: Colors.amberAccent,
child: Center(
child: Column(
children: <Widget>[
GestureDetector(
onTap: () => setState(() {
colorOfCustomPhysicsBoxOne = Colors.white;
}),
child: Container(
color: colorOfCustomPhysicsBoxOne,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfCustomPhysicsBoxTwo = Colors.white;
}),
child: Container(
color: colorOfCustomPhysicsBoxTwo,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfCustomPhysicsBoxThree = Colors.white;
}),
child: Container(
color: colorOfCustomPhysicsBoxThree,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfCustomPhysicsBoxFour = Colors.white;
}),
child: Container(
color: colorOfCustomPhysicsBoxFour,
height: 100.0,
width: 100.0,
),
),
GestureDetector(
onTap: () => setState(() {
colorOfCustomPhysicsBoxFive = Colors.white;
}),
child: Container(
color: colorOfCustomPhysicsBoxFive,
height: 100.0,
width: 100.0,
),
),
],
),
),
),
),
],
),
);
}
}
class CustomSnappingScrollPhysicsForTheControlPanelHousing extends ScrollPhysics {
List<double> stoppingPoints;
SpringDescription springDescription = SpringDescription(mass: 100.0, damping: .2, stiffness: 50.0);
@override
CustomSnappingScrollPhysicsForTheControlPanelHousing({@required this.stoppingPoints, ScrollPhysics parent})
: super(parent: parent) {
stoppingPoints.sort();
}
@override
CustomSnappingScrollPhysicsForTheControlPanelHousing applyTo(ScrollPhysics ancestor) {
return new CustomSnappingScrollPhysicsForTheControlPanelHousing(
stoppingPoints: stoppingPoints, parent: buildParent(ancestor));
}
@override
Simulation createBallisticSimulation(ScrollMetrics scrollMetrics, double velocity) {
double targetStoppingPoint = _getTargetStoppingPointPixels(scrollMetrics.pixels, velocity, 0.0003, stoppingPoints);
return ScrollSpringSimulation(springDescription, scrollMetrics.pixels, targetStoppingPoint, velocity,
tolerance: Tolerance(velocity: .00003, distance: .003));
}
double _getTargetStoppingPointPixels(
double initialPosition, double velocity, double drag, List<double> stoppingPoints) {
double endPointBeforeSnappingIsCalculated =
initialPosition + (-velocity / math.log(drag)).clamp(stoppingPoints[0], stoppingPoints.last);
if (stoppingPoints.contains(endPointBeforeSnappingIsCalculated)) {
return endPointBeforeSnappingIsCalculated;
}
if (endPointBeforeSnappingIsCalculated > stoppingPoints.last) {
return stoppingPoints.last;
}
for (int i = 0; i < stoppingPoints.length; i++) {
if (endPointBeforeSnappingIsCalculated < stoppingPoints[i] &&
endPointBeforeSnappingIsCalculated < stoppingPoints[i] - (stoppingPoints[i] - stoppingPoints[i - 1]) / 2) {
double stoppingPoint = stoppingPoints[i - 1];
debugPrint(stoppingPoint.toString());
return stoppingPoint;
} else if (endPointBeforeSnappingIsCalculated < stoppingPoints[i] &&
endPointBeforeSnappingIsCalculated > stoppingPoints[i] - (stoppingPoints[i] - stoppingPoints[i - 1]) / 2) {
double stoppingPoint = stoppingPoints[i];
debugPrint(stoppingPoint.toString());
return stoppingPoint;
}
}
throw Error.safeToString('Failed finding a new scroll simulation endpoint for this scroll animation');
}
}