在 PageView.builder 上使用时出现 RadioListTile 问题
RadioListTile issue when used on PageView.builder
- 我正在从 API 中提取测验数据，并使用 StreamBuilder
- 使用 PageView.builder 在单独的页面中显示每个问题和选项
- Options 的 RadioListTile 并使用地图迭代列表中的答案
问题是 --> 每当我 select 任何问题中的任何选项时，问题都会自动更改，但索引不会，我无法select 任何问题的任何选项。
我希望我能够很好地解释我的问题。
附加 JSON、PageView.Builder 代码。
页面视图控制器
PageController _pageViewController = PageController(initialPage: 0);
var currentPageIndex;
getCurrectPageIndex(index) {
setState(() {
currentPageIndex = index;
});
}
PageView 按钮
pageViewButtons(context, questionDataIndex, snapshotData, _pageViewController) {
bool isLastQues = questionDataIndex == snapshotData.last;
return Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
circularButton(
text: "Previous",
onPressed: () {
_pageViewController.previousPage(
duration: Duration(microseconds: 100), curve: Curves.ease);
},
color: brandBlue,
),
circularButton(
text: isLastQues ? "Finish" : "Next",
onPressed: (isLastQues)
? () {
showDialogBox(
context: context,
headingText: "Submit all answers?",
contentText:
"Press Submit to submit answers or Dismiss to cancel",
widget: ElevatedButton(
child: Text("Submit"),
onPressed: questionDataIndex == snapshotData.last
? () => Get.off(() => ResultView())
: null,
),
);
}
: () => _pageViewController.nextPage(
duration: Duration(microseconds: 100), curve: Curves.ease),
color: brandRed,
),
],
);
}
ElevatedButton circularButton(
{String? text, Function()? onPressed, Color? color}) {
return ElevatedButton(
child: Text(text!),
onPressed: onPressed,
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all<Color>(color!),
shape: MaterialStateProperty.all<OutlinedBorder?>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20),
),
),
),
);
}
分页码
_pagination(List<Response> snapshotData) {
return new Container(
width: deviceSize.width * 0.90,
height: deviceSize.height * 0.10,
child: GridView.builder(
itemCount: snapshotData.length,
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 5,
childAspectRatio: 5 / 2,
mainAxisSpacing: 10,
),
itemBuilder: (context, index) {
final indexValue = index;
final indexValuePlus1 = (index + 1).toString();
bool isEqual = indexValue == currentPageIndex;
return Container(
decoration: BoxDecoration(shape: BoxShape.circle),
margin: EdgeInsets.symmetric(horizontal: 5),
child: Material(
shape: CircleBorder(),
clipBehavior: Clip.hardEdge,
color: Colors.white,
child: InkWell(
child: CircleAvatar(
backgroundColor: () {
if (isEqual) {
return brandRed;
} else {
return brandBlue;
}
}(),
child: Padding(
padding: const EdgeInsets.all(2.0),
child: CircleAvatar(
child: Text(
indexValuePlus1,
style: TextStyle(color: Colors.black87, height: 1.2),
),
backgroundColor: Colors.white,
),
),
),
onTap: () {
_pageViewController.jumpToPage(indexValue);
},
),
),
);
},
),
);}
PageView.Builder
_pageView(List<Response> snapshotData, ThemeData themeContext) {
return PageView.builder(
controller: _pageViewController,
physics: NeverScrollableScrollPhysics(),
itemCount: snapshotData.length,
onPageChanged: getCurrectPageIndex,
itemBuilder: (context, index) {
questionDataIndex = snapshotData[index];
final questionTitle = questionDataIndex.title;
final questionAnswers = questionDataIndex.answer;
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
_pagination(snapshotData),
SizedBox(height: 20),
Expanded(
child: Stack(
alignment: AlignmentDirectional.topCenter,
clipBehavior: Clip.none,
children: [
Padding(
padding: kDefaultPadding,
child: Wrap(
children: [
Text(questionTitle.inCaps,
style: themeContext.textTheme.headline6!
.copyWith(fontWeight: FontWeight.bold)),
SizedBox(width: 20, height: 20),
...questionAnswers.map((answer) {
return RadioListTile(
key: new Key(answer.id.toString()),
dense: true,
title: Text(
answer.answerText.inCaps,
style: themeContext.textTheme.bodyText2,
),
value: answer.id,
groupValue: groupValue,
onChanged: (value) {
setState(() {
// groupValue = answer.id;
value = groupValue;
});
},
);
}).toList(),
],
),
)
],
),
),
],
);
},
);}
和JSON
{
"status": "success",
"response": [
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 20,
"title": "node.next -> node.next.next; will make",
"answer": [
{
"id": 26,
"answer_text": "node.next inaccessible"
},
{
"id": 27,
"answer_text": "node.next.next inaccessible"
},
{
"id": 28,
"answer_text": "this node inaccessible"
},
{
"id": 29,
"answer_text": "none of the above!"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 15,
"title": "For a binary search algorithm to work, it is necessary that the array (list) must be",
"answer": [
{
"id": 8,
"answer_text": "sorted"
},
{
"id": 9,
"answer_text": "Unsorted"
},
{
"id": 10,
"answer_text": "In a heap"
},
{
"id": 11,
"answer_text": "popped out of stack"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 22,
"title": "A pivot element to partition unsorted list is used in",
"answer": [
{
"id": 34,
"answer_text": "Merge Sort"
},
{
"id": 35,
"answer_text": "Quick Sort"
},
{
"id": 36,
"answer_text": "Insertion Sort"
},
{
"id": 37,
"answer_text": "Selection Sort"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 17,
"title": "Find the odd out",
"answer": [
{
"id": 14,
"answer_text": "Prim's Minimal Spanning Tree Algorithm"
},
{
"id": 15,
"answer_text": "Kruskal's Minimal Spanning Tree Algorithm"
},
{
"id": 16,
"answer_text": "Floyd-Warshall's All pair shortest path Algorithm"
},
{
"id": 17,
"answer_text": "Dijkstra's Minimal Spanning Tree Algorithm"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 23,
"title": "Apriori analysis of an algorithm assumes that −",
"answer": [
{
"id": 38,
"answer_text": "the algorithm has been tested before in real environment."
},
{
"id": 39,
"answer_text": "all other factors like CPU speed are constant and have no effect on implementation."
},
{
"id": 40,
"answer_text": "the algorithm needs not to be practical."
},
{
"id": 41,
"answer_text": "none of the above."
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 16,
"title": "Postfix expression is just a reverse of prefix expression.",
"answer": [
{
"id": 12,
"answer_text": "Yes"
},
{
"id": 13,
"answer_text": "No"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 18,
"title": "If the array is already sorted, which of these algorithms will exhibit the best performance",
"answer": [
{
"id": 18,
"answer_text": "Merge Sort"
},
{
"id": 19,
"answer_text": "Insertion Sort"
},
{
"id": 20,
"answer_text": "Quick Sort"
},
{
"id": 21,
"answer_text": "Heap Sort"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 21,
"title": "Which of the following algorithm cannot be desiged without recursion −",
"answer": [
{
"id": 30,
"answer_text": "Tower of Hanoi"
},
{
"id": 31,
"answer_text": "Fibonacci Series"
},
{
"id": 32,
"answer_text": "Tree Traversal"
},
{
"id": 33,
"answer_text": "None of the above"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 19,
"title": "Apriory algorithm analysis does not include −",
"answer": [
{
"id": 22,
"answer_text": "It is the easiest possible way."
},
{
"id": 23,
"answer_text": "To make sure that it is still complete binary tree."
},
{
"id": 24,
"answer_text": "Because left and right subtree might be missing."
},
{
"id": 25,
"answer_text": "None of the above!"
}
]
}
]}
Question change issue can be seen here
嘿，我不明白你的代码，但这是我所管理的：
import 'package:flutter/material.dart';
class TestScreen extends StatefulWidget {
@override
_TestScreenState createState() => _TestScreenState();
}
class _TestScreenState extends State<TestScreen> {
PageController controller = PageController();
int index = 0;
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.grey[100],
appBar: AppBar(
title: Text('Quiz'),
),
body: Container(
padding: EdgeInsets.all(10),
child: Column(
children: [
Container(
height: 105,
child: GridView(
physics: NeverScrollableScrollPhysics(),
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 5,
childAspectRatio: 3 / 2,
mainAxisSpacing: 10,
),
children: List.generate(
questions.length,
(index) => Container(
decoration: BoxDecoration(
color: Colors.white,
shape: BoxShape.circle,
border: Border.all(
color:
this.index == index ? Colors.red : Colors.lightBlue,
width: 2,
),
),
child: Center(
child: Text(
'${index + 1}',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 15,
),
),
),
),
),
),
),
SizedBox(height: 10),
Expanded(
child: Card(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(16),
),
child: Column(
children: [
Expanded(
child: PageView(
controller: controller,
physics: NeverScrollableScrollPhysics(),
children: List.generate(
questions.length,
(index) => Container(
padding: EdgeInsets.all(20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
questions[index]['title'],
style: TextStyle(
fontSize: 18,
fontWeight: FontWeight.bold,
),
),
SizedBox(height: 10),
// questions[index]['title'].forEach().
// questions.forEach((element) { }).toList
Expanded(
child: Column(
children: questions[index]['answer']
.map<Widget>(
(answer) => Container(
child: ListTile(
onTap: () {
nextPage();
},
leading: Icon(Icons
.radio_button_off_rounded),
title: Text(
answer['answer_text'],
),
),
),
)
.toList(),
),
),
],
),
),
),
),
),
Container(
padding: EdgeInsets.symmetric(horizontal: 16),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30),
),
),
padding: MaterialStateProperty.all(
EdgeInsets.symmetric(
horizontal: 20,
vertical: 12,
),
),
),
onPressed: () {
previousPage();
},
child: Text(
'Previous',
style: TextStyle(fontSize: 14),
),
),
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30),
),
),
padding: MaterialStateProperty.all(
EdgeInsets.symmetric(
horizontal: 20,
vertical: 12,
),
),
backgroundColor: MaterialStateProperty.all(
Colors.red[600],
),
),
onPressed: () {
nextPage();
},
child: Text(
'Next',
style: TextStyle(fontSize: 14),
),
),
],
),
),
SizedBox(height: 10),
],
),
),
),
],
),
),
);
}
void nextPage() {
if (index < 9) {
setState(() {
index++;
});
controller.jumpToPage(index);
print(index);
} else {
Navigator.of(context).pop();
}
}
void previousPage() {
if (index > 0) {
setState(() {
index--;
});
controller.jumpToPage(index);
print(index);
}
}
final List<Map<String, dynamic>> questions = [
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 20,
"title": "node.next -> node.next.next; will make",
"answer": [
{"id": 26, "answer_text": "node.next inaccessible"},
{"id": 27, "answer_text": "node.next.next inaccessible"},
{"id": 28, "answer_text": "this node inaccessible"},
{"id": 29, "answer_text": "none of the above!"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 15,
"title":
"For a binary search algorithm to work, it is necessary that the array (list) must be",
"answer": [
{"id": 8, "answer_text": "sorted"},
{"id": 9, "answer_text": "Unsorted"},
{"id": 10, "answer_text": "In a heap"},
{"id": 11, "answer_text": "popped out of stack"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 22,
"title": "A pivot element to partition unsorted list is used in",
"answer": [
{"id": 34, "answer_text": "Merge Sort"},
{"id": 35, "answer_text": "Quick Sort"},
{"id": 36, "answer_text": "Insertion Sort"},
{"id": 37, "answer_text": "Selection Sort"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 17,
"title": "Find the odd out",
"answer": [
{"id": 14, "answer_text": "Prim's Minimal Spanning Tree Algorithm"},
{"id": 15, "answer_text": "Kruskal's Minimal Spanning Tree Algorithm"},
{
"id": 16,
"answer_text": "Floyd-Warshall's All pair shortest path Algorithm"
},
{"id": 17, "answer_text": "Dijkstra's Minimal Spanning Tree Algorithm"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 23,
"title": "Apriori analysis of an algorithm assumes that −",
"answer": [
{
"id": 38,
"answer_text":
"the algorithm has been tested before in real environment."
},
{
"id": 39,
"answer_text":
"all other factors like CPU speed are constant and have no effect on implementation."
},
{"id": 40, "answer_text": "the algorithm needs not to be practical."},
{"id": 41, "answer_text": "none of the above."}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 16,
"title": "Postfix expression is just a reverse of prefix expression.",
"answer": [
{"id": 12, "answer_text": "Yes"},
{"id": 13, "answer_text": "No"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 18,
"title":
"If the array is already sorted, which of these algorithms will exhibit the best performance",
"answer": [
{"id": 18, "answer_text": "Merge Sort"},
{"id": 19, "answer_text": "Insertion Sort"},
{"id": 20, "answer_text": "Quick Sort"},
{"id": 21, "answer_text": "Heap Sort"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 21,
"title":
"Which of the following algorithm cannot be desiged without recursion −",
"answer": [
{"id": 30, "answer_text": "Tower of Hanoi"},
{"id": 31, "answer_text": "Fibonacci Series"},
{"id": 32, "answer_text": "Tree Traversal"},
{"id": 33, "answer_text": "None of the above"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 19,
"title": "Apriory algorithm analysis does not include −",
"answer": [
{"id": 22, "answer_text": "It is the easiest possible way."},
{
"id": 23,
"answer_text": "To make sure that it is still complete binary tree."
},
{
"id": 24,
"answer_text": "Because left and right subtree might be missing."
},
{"id": 25, "answer_text": "None of the above!"}
]
}
];
}
阅读它，您可能会了解如何修改自己的代码以使其正常工作。
- 我正在从 API 中提取测验数据，并使用 StreamBuilder
- 使用 PageView.builder 在单独的页面中显示每个问题和选项
- Options 的 RadioListTile 并使用地图迭代列表中的答案
问题是 --> 每当我 select 任何问题中的任何选项时，问题都会自动更改，但索引不会，我无法select 任何问题的任何选项。
我希望我能够很好地解释我的问题。
附加 JSON、PageView.Builder 代码。
页面视图控制器
PageController _pageViewController = PageController(initialPage: 0);
var currentPageIndex;
getCurrectPageIndex(index) {
setState(() {
currentPageIndex = index;
});
}
PageView 按钮
pageViewButtons(context, questionDataIndex, snapshotData, _pageViewController) {
bool isLastQues = questionDataIndex == snapshotData.last;
return Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
circularButton(
text: "Previous",
onPressed: () {
_pageViewController.previousPage(
duration: Duration(microseconds: 100), curve: Curves.ease);
},
color: brandBlue,
),
circularButton(
text: isLastQues ? "Finish" : "Next",
onPressed: (isLastQues)
? () {
showDialogBox(
context: context,
headingText: "Submit all answers?",
contentText:
"Press Submit to submit answers or Dismiss to cancel",
widget: ElevatedButton(
child: Text("Submit"),
onPressed: questionDataIndex == snapshotData.last
? () => Get.off(() => ResultView())
: null,
),
);
}
: () => _pageViewController.nextPage(
duration: Duration(microseconds: 100), curve: Curves.ease),
color: brandRed,
),
],
);
}
ElevatedButton circularButton(
{String? text, Function()? onPressed, Color? color}) {
return ElevatedButton(
child: Text(text!),
onPressed: onPressed,
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all<Color>(color!),
shape: MaterialStateProperty.all<OutlinedBorder?>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20),
),
),
),
);
}
分页码
_pagination(List<Response> snapshotData) {
return new Container(
width: deviceSize.width * 0.90,
height: deviceSize.height * 0.10,
child: GridView.builder(
itemCount: snapshotData.length,
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 5,
childAspectRatio: 5 / 2,
mainAxisSpacing: 10,
),
itemBuilder: (context, index) {
final indexValue = index;
final indexValuePlus1 = (index + 1).toString();
bool isEqual = indexValue == currentPageIndex;
return Container(
decoration: BoxDecoration(shape: BoxShape.circle),
margin: EdgeInsets.symmetric(horizontal: 5),
child: Material(
shape: CircleBorder(),
clipBehavior: Clip.hardEdge,
color: Colors.white,
child: InkWell(
child: CircleAvatar(
backgroundColor: () {
if (isEqual) {
return brandRed;
} else {
return brandBlue;
}
}(),
child: Padding(
padding: const EdgeInsets.all(2.0),
child: CircleAvatar(
child: Text(
indexValuePlus1,
style: TextStyle(color: Colors.black87, height: 1.2),
),
backgroundColor: Colors.white,
),
),
),
onTap: () {
_pageViewController.jumpToPage(indexValue);
},
),
),
);
},
),
);}
PageView.Builder
_pageView(List<Response> snapshotData, ThemeData themeContext) {
return PageView.builder(
controller: _pageViewController,
physics: NeverScrollableScrollPhysics(),
itemCount: snapshotData.length,
onPageChanged: getCurrectPageIndex,
itemBuilder: (context, index) {
questionDataIndex = snapshotData[index];
final questionTitle = questionDataIndex.title;
final questionAnswers = questionDataIndex.answer;
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
_pagination(snapshotData),
SizedBox(height: 20),
Expanded(
child: Stack(
alignment: AlignmentDirectional.topCenter,
clipBehavior: Clip.none,
children: [
Padding(
padding: kDefaultPadding,
child: Wrap(
children: [
Text(questionTitle.inCaps,
style: themeContext.textTheme.headline6!
.copyWith(fontWeight: FontWeight.bold)),
SizedBox(width: 20, height: 20),
...questionAnswers.map((answer) {
return RadioListTile(
key: new Key(answer.id.toString()),
dense: true,
title: Text(
answer.answerText.inCaps,
style: themeContext.textTheme.bodyText2,
),
value: answer.id,
groupValue: groupValue,
onChanged: (value) {
setState(() {
// groupValue = answer.id;
value = groupValue;
});
},
);
}).toList(),
],
),
)
],
),
),
],
);
},
);}
和JSON
{
"status": "success",
"response": [
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 20,
"title": "node.next -> node.next.next; will make",
"answer": [
{
"id": 26,
"answer_text": "node.next inaccessible"
},
{
"id": 27,
"answer_text": "node.next.next inaccessible"
},
{
"id": 28,
"answer_text": "this node inaccessible"
},
{
"id": 29,
"answer_text": "none of the above!"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 15,
"title": "For a binary search algorithm to work, it is necessary that the array (list) must be",
"answer": [
{
"id": 8,
"answer_text": "sorted"
},
{
"id": 9,
"answer_text": "Unsorted"
},
{
"id": 10,
"answer_text": "In a heap"
},
{
"id": 11,
"answer_text": "popped out of stack"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 22,
"title": "A pivot element to partition unsorted list is used in",
"answer": [
{
"id": 34,
"answer_text": "Merge Sort"
},
{
"id": 35,
"answer_text": "Quick Sort"
},
{
"id": 36,
"answer_text": "Insertion Sort"
},
{
"id": 37,
"answer_text": "Selection Sort"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 17,
"title": "Find the odd out",
"answer": [
{
"id": 14,
"answer_text": "Prim's Minimal Spanning Tree Algorithm"
},
{
"id": 15,
"answer_text": "Kruskal's Minimal Spanning Tree Algorithm"
},
{
"id": 16,
"answer_text": "Floyd-Warshall's All pair shortest path Algorithm"
},
{
"id": 17,
"answer_text": "Dijkstra's Minimal Spanning Tree Algorithm"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 23,
"title": "Apriori analysis of an algorithm assumes that −",
"answer": [
{
"id": 38,
"answer_text": "the algorithm has been tested before in real environment."
},
{
"id": 39,
"answer_text": "all other factors like CPU speed are constant and have no effect on implementation."
},
{
"id": 40,
"answer_text": "the algorithm needs not to be practical."
},
{
"id": 41,
"answer_text": "none of the above."
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 16,
"title": "Postfix expression is just a reverse of prefix expression.",
"answer": [
{
"id": 12,
"answer_text": "Yes"
},
{
"id": 13,
"answer_text": "No"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 18,
"title": "If the array is already sorted, which of these algorithms will exhibit the best performance",
"answer": [
{
"id": 18,
"answer_text": "Merge Sort"
},
{
"id": 19,
"answer_text": "Insertion Sort"
},
{
"id": 20,
"answer_text": "Quick Sort"
},
{
"id": 21,
"answer_text": "Heap Sort"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 21,
"title": "Which of the following algorithm cannot be desiged without recursion −",
"answer": [
{
"id": 30,
"answer_text": "Tower of Hanoi"
},
{
"id": 31,
"answer_text": "Fibonacci Series"
},
{
"id": 32,
"answer_text": "Tree Traversal"
},
{
"id": 33,
"answer_text": "None of the above"
}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 19,
"title": "Apriory algorithm analysis does not include −",
"answer": [
{
"id": 22,
"answer_text": "It is the easiest possible way."
},
{
"id": 23,
"answer_text": "To make sure that it is still complete binary tree."
},
{
"id": 24,
"answer_text": "Because left and right subtree might be missing."
},
{
"id": 25,
"answer_text": "None of the above!"
}
]
}
]}
Question change issue can be seen here
嘿，我不明白你的代码，但这是我所管理的：
import 'package:flutter/material.dart';
class TestScreen extends StatefulWidget {
@override
_TestScreenState createState() => _TestScreenState();
}
class _TestScreenState extends State<TestScreen> {
PageController controller = PageController();
int index = 0;
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.grey[100],
appBar: AppBar(
title: Text('Quiz'),
),
body: Container(
padding: EdgeInsets.all(10),
child: Column(
children: [
Container(
height: 105,
child: GridView(
physics: NeverScrollableScrollPhysics(),
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 5,
childAspectRatio: 3 / 2,
mainAxisSpacing: 10,
),
children: List.generate(
questions.length,
(index) => Container(
decoration: BoxDecoration(
color: Colors.white,
shape: BoxShape.circle,
border: Border.all(
color:
this.index == index ? Colors.red : Colors.lightBlue,
width: 2,
),
),
child: Center(
child: Text(
'${index + 1}',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 15,
),
),
),
),
),
),
),
SizedBox(height: 10),
Expanded(
child: Card(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(16),
),
child: Column(
children: [
Expanded(
child: PageView(
controller: controller,
physics: NeverScrollableScrollPhysics(),
children: List.generate(
questions.length,
(index) => Container(
padding: EdgeInsets.all(20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
questions[index]['title'],
style: TextStyle(
fontSize: 18,
fontWeight: FontWeight.bold,
),
),
SizedBox(height: 10),
// questions[index]['title'].forEach().
// questions.forEach((element) { }).toList
Expanded(
child: Column(
children: questions[index]['answer']
.map<Widget>(
(answer) => Container(
child: ListTile(
onTap: () {
nextPage();
},
leading: Icon(Icons
.radio_button_off_rounded),
title: Text(
answer['answer_text'],
),
),
),
)
.toList(),
),
),
],
),
),
),
),
),
Container(
padding: EdgeInsets.symmetric(horizontal: 16),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30),
),
),
padding: MaterialStateProperty.all(
EdgeInsets.symmetric(
horizontal: 20,
vertical: 12,
),
),
),
onPressed: () {
previousPage();
},
child: Text(
'Previous',
style: TextStyle(fontSize: 14),
),
),
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30),
),
),
padding: MaterialStateProperty.all(
EdgeInsets.symmetric(
horizontal: 20,
vertical: 12,
),
),
backgroundColor: MaterialStateProperty.all(
Colors.red[600],
),
),
onPressed: () {
nextPage();
},
child: Text(
'Next',
style: TextStyle(fontSize: 14),
),
),
],
),
),
SizedBox(height: 10),
],
),
),
),
],
),
),
);
}
void nextPage() {
if (index < 9) {
setState(() {
index++;
});
controller.jumpToPage(index);
print(index);
} else {
Navigator.of(context).pop();
}
}
void previousPage() {
if (index > 0) {
setState(() {
index--;
});
controller.jumpToPage(index);
print(index);
}
}
final List<Map<String, dynamic>> questions = [
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 20,
"title": "node.next -> node.next.next; will make",
"answer": [
{"id": 26, "answer_text": "node.next inaccessible"},
{"id": 27, "answer_text": "node.next.next inaccessible"},
{"id": 28, "answer_text": "this node inaccessible"},
{"id": 29, "answer_text": "none of the above!"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 15,
"title":
"For a binary search algorithm to work, it is necessary that the array (list) must be",
"answer": [
{"id": 8, "answer_text": "sorted"},
{"id": 9, "answer_text": "Unsorted"},
{"id": 10, "answer_text": "In a heap"},
{"id": 11, "answer_text": "popped out of stack"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 22,
"title": "A pivot element to partition unsorted list is used in",
"answer": [
{"id": 34, "answer_text": "Merge Sort"},
{"id": 35, "answer_text": "Quick Sort"},
{"id": 36, "answer_text": "Insertion Sort"},
{"id": 37, "answer_text": "Selection Sort"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 17,
"title": "Find the odd out",
"answer": [
{"id": 14, "answer_text": "Prim's Minimal Spanning Tree Algorithm"},
{"id": 15, "answer_text": "Kruskal's Minimal Spanning Tree Algorithm"},
{
"id": 16,
"answer_text": "Floyd-Warshall's All pair shortest path Algorithm"
},
{"id": 17, "answer_text": "Dijkstra's Minimal Spanning Tree Algorithm"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 23,
"title": "Apriori analysis of an algorithm assumes that −",
"answer": [
{
"id": 38,
"answer_text":
"the algorithm has been tested before in real environment."
},
{
"id": 39,
"answer_text":
"all other factors like CPU speed are constant and have no effect on implementation."
},
{"id": 40, "answer_text": "the algorithm needs not to be practical."},
{"id": 41, "answer_text": "none of the above."}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 16,
"title": "Postfix expression is just a reverse of prefix expression.",
"answer": [
{"id": 12, "answer_text": "Yes"},
{"id": 13, "answer_text": "No"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 18,
"title":
"If the array is already sorted, which of these algorithms will exhibit the best performance",
"answer": [
{"id": 18, "answer_text": "Merge Sort"},
{"id": 19, "answer_text": "Insertion Sort"},
{"id": 20, "answer_text": "Quick Sort"},
{"id": 21, "answer_text": "Heap Sort"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 21,
"title":
"Which of the following algorithm cannot be desiged without recursion −",
"answer": [
{"id": 30, "answer_text": "Tower of Hanoi"},
{"id": 31, "answer_text": "Fibonacci Series"},
{"id": 32, "answer_text": "Tree Traversal"},
{"id": 33, "answer_text": "None of the above"}
]
},
{
"question_type": "Multiple Choice",
"difficulty": "Fundamental",
"id": 19,
"title": "Apriory algorithm analysis does not include −",
"answer": [
{"id": 22, "answer_text": "It is the easiest possible way."},
{
"id": 23,
"answer_text": "To make sure that it is still complete binary tree."
},
{
"id": 24,
"answer_text": "Because left and right subtree might be missing."
},
{"id": 25, "answer_text": "None of the above!"}
]
}
];
}
阅读它，您可能会了解如何修改自己的代码以使其正常工作。