[英]Failed assertion: line 184 pos 12: 'end >= begin': is not true
如何解決以下錯誤：
======== Exception caught by widgets library =======================================================
The following assertion was thrown building AnimatedBuilder(animation: AnimationController#eedf7(▶ 0.111), dirty, state: _AnimatedState#2b432):
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=BUG.md
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
When the exception was thrown, this was the stack:
#2 Interval.transformInternal (package:flutter/src/animation/curves.dart:184:12)
#3 ParametricCurve.transform (package:flutter/src/animation/curves.dart:38:12)
#4 Curve.transform (package:flutter/src/animation/curves.dart:92:18)
#5 CurvedAnimation.value (package:flutter/src/animation/animations.dart:453:24)
#6 _PizzaDetailsState._buildIngredientsWidget (package:makefood/pizza/home/pizza_order_details.dart:101:69)
...
====================================================================================================
======== Exception caught by widgets library =======================================================
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
====================================================================================================
======== Exception caught by widgets library =======================================================
The following assertion was thrown building AnimatedBuilder(animation: AnimationController#eedf7(▶ 0.334), dirty, state: _AnimatedState#2b432):
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=BUG.md
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
When the exception was thrown, this was the stack:
#2 Interval.transformInternal (package:flutter/src/animation/curves.dart:184:12)
#3 ParametricCurve.transform (package:flutter/src/animation/curves.dart:38:12)
#4 Curve.transform (package:flutter/src/animation/curves.dart:92:18)
#5 CurvedAnimation.value (package:flutter/src/animation/animations.dart:453:24)
#6 _PizzaDetailsState._buildIngredientsWidget (package:makefood/pizza/home/pizza_order_details.dart:101:69)
...
====================================================================================================
======== Exception caught by widgets library =======================================================
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
====================================================================================================
======== Exception caught by widgets library =======================================================
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
====================================================================================================
======== Exception caught by widgets library =======================================================
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
====================================================================================================
======== Exception caught by widgets library =======================================================
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
====================================================================================================
======== Exception caught by widgets library =======================================================
The following assertion was thrown building AnimatedBuilder(animation: AnimationController#eedf7(▶ 0.908), dirty, state: _AnimatedState#2b432):
'package:flutter/src/animation/curves.dart': Failed assertion: line 184 pos 12: 'end >= begin': is not true.
Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=BUG.md
The relevant error-causing widget was:
AnimatedBuilder file:///Users/mahmoudalharoon/Desktop/FoodProject/makefood/lib/pizza/home/pizza_order_details.dart:331:9
When the exception was thrown, this was the stack:
#2 Interval.transformInternal (package:flutter/src/animation/curves.dart:184:12)
#3 ParametricCurve.transform (package:flutter/src/animation/curves.dart:38:12)
#4 Curve.transform (package:flutter/src/animation/curves.dart:92:18)
#5 CurvedAnimation.value (package:flutter/src/animation/animations.dart:453:24)
#6 _PizzaDetailsState._buildIngredientsWidget (package:makefood/pizza/home/pizza_order_details.dart:101:69)
...
====================================================================================================
這是錯誤，如下圖所示
這是_buildIngredientAnimation方法
void _buildIngredientAnimation() {
_animationList.clear();
_animationList.add(
CurvedAnimation(
curve: Interval(
0.0,
0.8,
curve: Curves.decelerate,
),
parent: _animationController,
),
);
_animationList.add(
CurvedAnimation(
curve: Interval(
0.2,
0.8,
curve: Curves.decelerate,
),
parent: _animationController),
);
_animationList.add(
CurvedAnimation(
curve: Interval(
0.4,
1.0,
curve: Curves.decelerate,
),
parent: _animationController),
);
_animationList.add(
CurvedAnimation(
curve: Interval(
1.0,
0.7,
curve: Curves.decelerate,
),
parent: _animationController),
);
_animationList.add(
CurvedAnimation(
curve: Interval(
0.3,
1.0,
curve: Curves.decelerate,
),
parent: _animationController),
);
}
這是構建小部件方法：
Widget _buildIngredientsWidget() {
List<Widget> elements = [];
if (_animationList.isNotEmpty) {
for (int i = 0; i < _listIngredients.length; i++) {
Ingredient ingredient = _listIngredients[i];
final ingredientWidget = Image.asset(ingredient.image, height: 40);
for (int j = 0; j < ingredient.positions.length; j++) {
final animation = _animationList[j];
final position = ingredient.positions[j];
final positionX = position.dx;
final positionY = position.dy;
if (i == _listIngredients.length - 1) {
double fromX = 0.0, fromY = 0.0;
if (j < 1) {
fromX = -_pizzaConstraints.maxWidth * (1 - animation.value);
} else if (j < 2) {
fromX = _pizzaConstraints.maxWidth * (1 - animation.value);
} else if (j < 4) {
fromY = -_pizzaConstraints.maxHeight * (1 - animation.value);
} else {
fromY = _pizzaConstraints.maxHeight * (1 - animation.value);
}
if (animation.value > 0) {
elements.add(
Transform(
transform: Matrix4.identity()
..translate(
fromX + _pizzaConstraints.maxWidth * positionX,
fromY + _pizzaConstraints.maxHeight * positionY,
),
child: ingredientWidget,
),
);
}
} else {
elements.add(
Transform(
transform: Matrix4.identity()
..translate(
_pizzaConstraints.maxWidth * positionX,
_pizzaConstraints.maxHeight * positionY,
),
child: ingredientWidget,
),
);
}
}
}
return Stack(
children: elements,
);
}
return SizedBox.fromSize();
}
這是下面的構建方法，因為我將動畫構建器稱為以下代碼：
@override
Widget build(BuildContext context) {
return Stack(
children: [
Column(
children: [
Expanded(
child: DragTarget<Ingredient>(
onAccept: (ingredient) {
print('onAccept');
_notifierFocused.value = false;
setState(() {
_listIngredients.add(ingredient);
_total++;
});
_buildIngredientAnimation();
_animationController.forward(from: 0.0);
},
onWillAccept: (ingredient) {
print('onWillAccept');
_notifierFocused.value = true;
for (Ingredient i in _listIngredients) {
if (i.compare(ingredient)) {
return false;
}
}
return true;
},
onLeave: (ingredient) {
print('onLeave');
_notifierFocused.value = false;
},
builder: (context, list, rejects) {
return LayoutBuilder(
builder: (context, constraints) {
_pizzaConstraints = constraints;
return Center(
child: ValueListenableBuilder<bool>(
valueListenable: _notifierFocused,
builder: (context, focused, _) {
return AnimatedContainer(
duration: const Duration(milliseconds: 400),
height: focused
? constraints.maxHeight
: constraints.maxHeight - 10,
child: Stack(
children: [
Image.asset('assets/images/dish.png'),
Padding(
padding: const EdgeInsets.all(10.0),
child: Image.asset(
'assets/images/pizza-1.png'),
),
],
),
);
}),
);
},
);
},
),
),
const SizedBox(
height: 5,
),
AnimatedSwitcher(
duration: const Duration(milliseconds: 300),
return FadeTransition(
opacity: animation,
child: SlideTransition(
position: animation.drive(
Tween<Offset>(
begin: Offset(0.0, 0.0),
end: Offset(0.0, animation.value),
),
),
child: child,
),
);
},
child: Text(
'\$$_total',
// key: Key(_total.toString()),
key: UniqueKey(),
style: TextStyle(
fontSize: 26,
fontWeight: FontWeight.bold,
color: Colors.cyan,
),
),
)
],
),
AnimatedBuilder(
animation: _animationController,
builder: (context, _) {
return _buildIngredientsWidget();
}),
],
);
這是下面的完整代碼：
import 'package:flutter/material.dart';
import 'package:makefood/pizza/ingredient.dart';
const _pizzaCartSize = 55.0;
class PizzaOrderDetails extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(
'New Order Pizza',
style: TextStyle(
color: Colors.cyan,
fontSize: 29,
),
),
backgroundColor: Colors.white,
elevation: 0,
actions: [
IconButton(
icon: Icon(
Icons.add_shopping_cart,
color: Colors.cyan,
),
onPressed: () {},
),
],
),
body: Stack(
children: [
Positioned.fill(
bottom: 50,
right: 10,
left: 10,
child: Card(
elevation: 10,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20),
),
child: Column(
children: [
Expanded(
flex: 3,
child: _PizzaDetails(),
),
Expanded(
flex: 2,
child: _PizzaIngredients(),
),
],
),
),
),
Positioned(
height: _pizzaCartSize,
width: _pizzaCartSize,
left: MediaQuery.of(context).size.width / 2 - _pizzaCartSize / 2,
bottom: 25,
child: _PizzaCartButton(),
)
],
),
);
}
}
class _PizzaDetails extends StatefulWidget {
@override
_PizzaDetailsState createState() => _PizzaDetailsState();
}
class _PizzaDetailsState extends State<_PizzaDetails>
with SingleTickerProviderStateMixin {
final _listIngredients = List<Ingredient>();
// final _listIngredients = <Ingredient>[];
AnimationController _animationController;
int _total = 15;
final _notifierFocused = ValueNotifier(false);
List<Animation> _animationList = <Animation>[];
BoxConstraints _pizzaConstraints;
Widget _buildIngredientsWidget() {
List<Widget> elements = [];
if (_animationList.isNotEmpty) {
for (int i = 0; i < _listIngredients.length; i++) {
Ingredient ingredient = _listIngredients[i];
final ingredientWidget = Image.asset(ingredient.image, height: 40);
for (int j = 0; j < ingredient.positions.length; j++) {
final animation = _animationList[j];
final position = ingredient.positions[j];
final positionX = position.dx;
final positionY = position.dy;
double fromX = 0.0, fromY = 0.0;
if (j < 1) {
fromX = -_pizzaConstraints.maxWidth * (1 - animation.value);
} else if (j < 2) {
fromX = _pizzaConstraints.maxWidth * (1 - animation.value);
} else if (j < 4) {
fromY = -_pizzaConstraints.maxHeight * (1 - animation.value);
} else {
fromY = _pizzaConstraints.maxHeight * (1 - animation.value);
}
elements.add(
Transform(
transform: Matrix4.identity()
..translate(
fromX + _pizzaConstraints.maxWidth * positionX,
fromY + _pizzaConstraints.maxHeight * positionY,
),
child: ingredientWidget,
),
);
}
}
return Stack(
children: elements,
);
}
return SizedBox.fromSize();
}
void _buildIngredientAnimation() {
_animationList.clear();
_animationList.add(CurvedAnimation(
curve: Interval(0.0, 0.8, curve: Curves.decelerate),
parent: _animationController,
));
_animationList.add(CurvedAnimation(
curve: Interval(0.2, 0.8, curve: Curves.decelerate),
parent: _animationController,
));
_animationList.add(CurvedAnimation(
curve: Interval(0.4, 1.0, curve: Curves.decelerate),
parent: _animationController,
));
_animationList.add(CurvedAnimation(
curve: Interval(1.0, 0.7, curve: Curves.decelerate),
parent: _animationController,
));
_animationList.add(CurvedAnimation(
curve: Interval(0.3, 1.0, curve: Curves.decelerate),
parent: _animationController,
));
}
@override
void initState() {
_animationController = AnimationController(
vsync: this,
duration: const Duration(milliseconds: 900),
);
super.initState();
}
@override
void dispose() {
_animationController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Stack(
children: [
Column(
children: [
Expanded(
child: DragTarget<Ingredient>(
onAccept: (ingredient) {
print('onAccept');
_notifierFocused.value = false;
setState(() {
_listIngredients.add(ingredient);
_total++;
});
_buildIngredientAnimation();
_animationController.forward(from: 0.0);
},
onWillAccept: (ingredient) {
print('onWillAccept');
_notifierFocused.value = true;
for (Ingredient i in _listIngredients) {
if (i.compare(ingredient)) {
return false;
}
}
return true;
},
onLeave: (ingredient) {
print('onLeave');
_notifierFocused.value = false;
},
builder: (context, list, rejects) {
return LayoutBuilder(
builder: (context, constraints) {
_pizzaConstraints = constraints;
return Center(
child: ValueListenableBuilder<bool>(
valueListenable: _notifierFocused,
builder: (context, focused, _) {
return AnimatedContainer(
duration: const Duration(milliseconds: 400),
height: focused
? constraints.maxHeight
: constraints.maxHeight - 10,
child: Stack(
children: [
Image.asset('assets/images/dish.png'),
Padding(
padding: const EdgeInsets.all(10.0),
child: Image.asset(
'assets/images/pizza-1.png'),
),
],
),
);
}),
);
},
);
},
),
),
const SizedBox(
height: 5,
),
AnimatedSwitcher(
duration: const Duration(milliseconds: 300),
// layoutBuilder: (Widget currentChild, List<Widget> previousChildren) {
transitionBuilder: (child, animation) {
return FadeTransition(
opacity: animation,
child: SlideTransition(
position: animation.drive(
Tween<Offset>(
begin: Offset(0.0, 0.0),
end: Offset(0.0, animation.value),
),
),
child: child,
),
);
},
child: Text(
'\$$_total',
// key: Key(_total.toString()),
key: UniqueKey(),
style: TextStyle(
fontSize: 30,
fontWeight: FontWeight.bold,
color: Colors.cyan,
),
),
)
],
),
AnimatedBuilder(
animation: _animationController,
builder: (context, child) {
return _buildIngredientsWidget();
}),
],
);
}
}
class _PizzaCartButton extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(5),
gradient: LinearGradient(
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
colors: [
Colors.cyan.withOpacity(0.5),
Colors.cyan,
],
),
),
child: Icon(
Icons.shopping_bag_outlined,
color: Colors.white,
size: 35,
),
);
}
}
class _PizzaIngredients extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView.builder(
scrollDirection: Axis.horizontal,
itemCount: ingredients.length,
itemBuilder: (context, index) {
final ingredient = ingredients[index];
return _PizzaIngredientItem(ingredient: ingredient);
},
);
}
}
class _PizzaIngredientItem extends StatelessWidget {
const _PizzaIngredientItem({Key key, this.ingredient}) : super(key: key);
final Ingredient ingredient;
@override
Widget build(BuildContext context) {
final child = Padding(
padding: const EdgeInsets.symmetric(horizontal: 8.0),
child: Container(
height: 45,
width: 45,
decoration: BoxDecoration(
color: Color(0xFFF5EED3),
shape: BoxShape.circle,
),
child: Padding(
padding: const EdgeInsets.all(5.0),
child: Image.asset(
ingredient.image,
fit: BoxFit.contain,
),
),
),
);
return Center(
child: Draggable(
feedback: DecoratedBox(
decoration: BoxDecoration(shape: BoxShape.circle, boxShadow: [
BoxShadow(
blurRadius: 10.0,
color: Colors.black26,
offset: Offset(0.0, 5.0),
spreadRadius: 10.0,
),
]),
child: child,
),
data: ingredient,
child: child,
),
);
}
}
這里還有成分 class：
import 'package:flutter/rendering.dart';
class Ingredient {
const Ingredient(this.image, this.positions);
final String image;
final List<Offset> positions;
bool compare(Ingredient ingredient) => ingredient.image == image;
}
final ingredients = const <Ingredient>[
Ingredient(
'assets/images/chili.png',
<Offset>[
Offset(0.2, 0.2),
Offset(0.6, 0.2),
Offset(0.4, 0.25),
Offset(0.5, 0.3),
Offset(0.4, 0.65),
],
),
Ingredient(
'assets/images/garlic.png',
<Offset>[
Offset(0.2, 0.35),
Offset(0.65, 0.35),
Offset(0.3, 0.23),
Offset(0.5, 0.2),
Offset(0.3, 0.5),
],
),
Ingredient(
'assets/images/olive.png',
<Offset>[
Offset(0.25, 0.5),
Offset(0.65, 0.6),
Offset(0.2, 0.3),
Offset(0.4, 0.2),
Offset(0.2, 0.6),
],
),
Ingredient(
'assets/images/onion.png',
<Offset>[
Offset(0.2, 0.65),
Offset(0.65, 0.3),
Offset(0.25, 0.25),
Offset(0.45, 0.35),
Offset(0.4, 0.65),
],
),
Ingredient(
'assets/images/pea.png',
<Offset>[
Offset(0.2, 0.35),
Offset(0.65, 0.35),
Offset(0.3, 0.23),
Offset(0.5, 0.2),
Offset(0.3, 0.5),
],
),
Ingredient(
'assets/images/pickle.png',
<Offset>[
Offset(0.2, 0.65),
Offset(0.65, 0.3),
Offset(0.25, 0.25),
Offset(0.45, 0.35),
Offset(0.4, 0.65),
],
),
Ingredient(
'assets/images/potato.png',
<Offset>[
Offset(0.2, 0.2),
Offset(0.6, 0.2),
Offset(0.4, 0.25),
Offset(0.5, 0.3),
Offset(0.4, 0.65),
],
),
];
_animationList.add(
CurvedAnimation(
curve: Interval(
1.0,
0.7,
curve: Curves.decelerate,
),
parent: _animationController),
);
查看此代碼行，間隔從 1.0 開始，到 0.7 結束。 結束應始終大於開始。 我有同樣的錯誤:) 希望這會有所幫助。
失敗的斷言：第 549 行 pos 12：“child.hasSize”：不正確
[英]Failed assertion: line 549 pos 12: 'child.hasSize': is not true
失敗的斷言：第 1696 行 pos 12：'center!.parent == this'：不是真的
[英]Failed assertion: line 1696 pos 12: 'center!.parent == this': is not true
斷言失敗：第 6292 行第 12 行：'child == _child'：不是真的
[英]Failed assertion: line 6292 pos 12: 'child == _child': is not true
斷言失敗：第 1205 行第 12 行：'<optimized out> '：不是真的</optimized>
[英]Failed assertion: line 1205 pos 12: '<optimized out>': is not true
失敗的斷言：第 551 行 pos 12：“child.hasSize”：不正確
[英]Failed assertion: line 551 pos 12: 'child.hasSize': is not true
失敗的斷言：第 5070 行 pos 12：'<optimized out> ': 不是真的
[英]Failed assertion: line 5070 pos 12: '<optimized out>': is not true
斷言行 5120 pos 12 失敗：'child = _child' 不是真的
[英]Failed assertion line 5120 pos 12: 'child = _child' is not true
失敗的斷言：第 6075 行 pos 12：'child == _child'：不是真的
[英]Failed assertion: line 6075 pos 12: 'child == _child': is not true
斷言失敗：第 4429 行 pos 12：“：_debugLocked”：不是真的
[英]Failed assertion: line 4429 pos 12: '!_debugLocked': is not true
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