Flutter 颤振：如何渲染贴图列表
我遇到了一个问题。我正在尝试制作一个多选应用程序，我需要显示多选答案选项列表中的所有地图。我没有问题显示问题的数量，但我需要选项列表中的所有文本。问题是我只能显示一个选项，而不是所有选项 - 为这个关系写一个等式。Flutter 颤振：如何渲染贴图列表,flutter,dart,flutter-test,Flutter,Dart,Flutter Test,我遇到了一个问题。我正在尝试制作一个多选应用程序，我需要显示多选答案选项列表中的所有地图。我没有问题显示问题的数量，但我需要选项列表中的所有文本。问题是我只能显示一个选项，而不是所有选项 - 为这个关系写一个等式。 A.y=1/5x B.y=1/2x C.y=2x D.y=5x 而不是 为这个关系写一个等式。 A.y=1/5x 注意：每个问题包含不同的选项范围，例如问题1包含4个选项，问题2可能包含2个选项 我已经成功地序列化了JSON。简而言之，这是包含我的问题的JSON文件 "qu
A.y=1/5x
B.y=1/2x
C.y=2x
D.y=5x 而不是
A.y=1/5x
"questions": [
{
"_id": "5a13431102b92110003fdb8c",
"createdAt": "2017-11-20T21:03:13.963Z",
"updated": "2020-09-03T18:30:39.891Z",
"time": 300000,
"type": "MCQ",
"published": true,
"structure": {
"kind": "MCQ",
"query": {
"type": "text-image",
"media": [
{
"type": "image",
"url": "https://quizizz.com/media/resource/gs/quizizz-media/questions/L2FwcGhvc3RpbmdfcHJvZC9ibG9icy9BRW5CMlVwajVWZnl0S2RBRXpIazROejFaSTl0dkU3Rmt6cjhtcTRvTGVxeFJzeHVLQzlZa3hzYjNZdkpNa3N1TTItaE5UNmVHUUZVdl9ZdTR6YnNaTk5hV0luZWhZQm9sUS5pOTBwLU1YLUtMRXR5YlBZ"
}
],
"text": "Write an equation for this relationship.",
"hasMath": false
},
"options": [
{
"type": "text",
"text": "y=1/5x",
"media": [],
"hasMath": false
},
{
"type": "text",
"text": "y=1/2x",
"media": [],
"hasMath": false
},
{
"type": "text",
"text": "y=2x",
"media": [],
"hasMath": false
},
{
"type": "text",
"text": "y=5x",
"media": [],
"hasMath": false
}
],
"answer": 3,
"settings": {
"hasCorrectAnswer": true
}
},
"standards": [],
"topics": [],
"cached": true
},
{
"type": "MCQ",
"published": true,
"structure": {
"settings": {
"hasCorrectAnswer": true
},
"explain": null,
"kind": "MCQ",
"options": [
{
"math": {
"latex": []
},
"type": "text",
"hasMath": false,
"media": [],
"text": "Line L"
},
{
"math": {
"latex": []
},
"type": "text",
"hasMath": false,
"media": [],
"text": "Line M"
}
],
"query": {
"math": {
"latex": []
},
"type": "text-image",
"hasMath": false,
"media": [
{
"type": "image",
"url": "https://quizizz.com/media/resource/gs/quizizz-media/questions/L2FwcGhvc3RpbmdfcHJvZC9ibG9icy9BRW5CMlVyUDVXUV9kUEg0QmFVd0Y2WnlIalBqbDkweDZfVTRxQTZEQktGaVBPZ1R3VHNZeEM3SGZ0QllOUzUyWGdES3o2N3IzLXhnN1hueTNTS25zaVBzUFB2bTcyM29ady41OGdlemxaMlVaYlJhRmli"
}
],
"text": "Which line shows a proportional relationship between x and y?"
},
"answer": 0
},
"standards": [],
"topics": [],
"_id": "580049efaa65fc295e4a83ff",
"createdAt": "2016-10-14T02:58:55.180Z",
"updated": "2020-09-03T18:30:39.891Z",
"time": 30000
},
{
"_id": "580049efaa65fc295e4a8400",
"createdAt": "2016-10-14T02:58:55.180Z",
"updated": "2020-09-03T18:30:39.891Z",
"time": 30000,
"type": "MCQ",
"published": true,
"structure": {
"kind": "MCQ",
"query": {
"type": "text-image",
"media": [
{
"type": "image",
"url": "https://quizizz.com/media/resource/gs/quizizz-media/questions/L2FwcGhvc3RpbmdfcHJvZC9ibG9icy9BRW5CMlVxTDdiaGVJTmZwb2d5ZlZ3VHMzUzRocTZ0SVBvbVRqY3g5eVZpZnlRaHRQZzZQMFZHMFZLX3FzbndPOFpGUXAxdi1uTVJ5aDlBQzNEVHFlN1NZaFFTbF9jSkpmTVF6amwtSTVzY0ZOVUpYaGEzaFFlUS51WHFpMjU5Z2djS0VsYmpF"
}
],
"text": "What is the unit rate in this proportional relationship?",
"hasMath": false
},
"options": [
{
"type": "text",
"text": "60 miles/1 hour",
"media": [],
"hasMath": false
},
{
"type": "text",
"text": "120 miles/ 2 hours",
"media": [],
"hasMath": false
},
{
"type": "text",
"text": "1 mile/ 1 hour",
"media": [],
"hasMath": false
}
],
"answer": 0,
"settings": {
"hasCorrectAnswer": true
}
},
"standards": [],
"topics": [],
"cached": true
},
{
"_id": "580049efaa65fc295e4a8401",
"createdAt": "2016-10-14T02:58:55.180Z",
"updated": "2020-09-01T14:35:17.749Z",
"time": 30000,
"type": "MCQ",
"published": true,
"structure": {
"kind": "MCQ",
"query": {
"type": "text-image",
"media": [
{
"type": "image",
"url": "https://quizizz.com/media/resource/gs/quizizz-media/questions/L2FwcGhvc3RpbmdfcHJvZC9ibG9icy9BRW5CMlVxVDFSaFU2MmpZZUF2R1dVZnV3Wlg4bDJ1N19JeHRRRHBYdXRPbTNfTHdWRHZTUXBkWkw0bjBtcDZoSFVCOUFhRFpxZnJqd0J1SUpaYkV1dlZzajczU3FjMlYxYTJWRk0xcGNHUWlhTzh4UGtHQW5DZy5mS1VFYjEtN2hzTllQVnY2"
}
],
"text": "Which statement best describes the relationship between x and y in the table?",
"hasMath": false
},
"options": [
{
"type": "text",
"text": "Proportional",
"media": [],
"hasMath": false
},
{
"type": "text",
"text": "Not Proportional",
"media": [],
"hasMath": false
}
],
"answer": 0,
"settings": {
"hasCorrectAnswer": true
}
},
"standards": [],
"topics": [],
"cached": true
}
]
SliverList(
delegate: SliverChildBuilderDelegate(
(context, index) {
return Padding(
padding: const EdgeInsets.only(top: 8.0),
child: Card(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10.0),
),
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
Image.network(
question.data.quiz.info.questions[index]
.structure.query.media.isEmpty
? "https://moorestown-mall.com/noimage.gif"
: question.data.quiz.info.questions[index]
.structure.query.media[0].url,
fit: BoxFit.cover,
), //Display the image of questions
Text(
"${index + 1}. ${question.data.quiz.info.questions[index].structure.query.text}",
style: TextStyle(fontSize: 18.0),
), //Display the questions
Text(question.data.quiz.info.questions[index].structure.options.toString(), style: TextStyle(fontSize: 16.0),), //Display the options
],
),
),
),
);
},
childCount: question.data.quiz.info.questions.length,
),
)
],
),
SliverList(
代表：SliverChildBuilderDelegate(
（上下文、索引）{
返回填充(
填充：仅限常量边集（顶部：8.0），
孩子：卡片(
形状：圆形矩形边框(
边界半径：边界半径。圆形（10.0），
),
孩子：填充(
填充：常数边集全部（10.0），
子：列(
crossAxisAlignment:crossAxisAlignment.stretch，
儿童：[
图像网络(
问题.数据.测验.信息.问题[索引]
.structure.query.media.isEmpty
? "https://moorestown-mall.com/noimage.gif"
：问题.数据.测验.信息.问题[索引]
.structure.query.media[0]。url，
适合：BoxFit.cover，
)，//显示问题的图像
正文(
“${index+1}.${question.data.quick.info.questions[index].structure.query.text}”，
样式：TextStyle（fontSize:18.0），
)，//显示问题
Text（question.data.quick.info.questions[index].structure.options.toString（），样式：TextStyle（fontSize:16.0），//显示选项
],
),
),
),
);
},
childCount:question.data.quick.info.questions.length，
),
)
],
),
> Performing hot reload...
> Reloaded 2 of 624 libraries in 1,074ms. I/flutter ( 9332): ══╡
> EXCEPTION CAUGHT BY WIDGETS LIBRARY
> ╞═══════════════════════════════════════════════════════════ I/flutter
> ( 9332): The following RangeError was thrown building: I/flutter (
> 9332): RangeError (index): Invalid value: Not in inclusive range 0..1:
> 2 I/flutter ( 9332): I/flutter ( 9332): When the exception was thrown,
> this was the stack: I/flutter ( 9332): #0 List.[]
> (dart:core-patch/growable_array.dart:177:60) I/flutter ( 9332): #1
> HomePage.build.<anonymous closure>
> (package:quizizz_cheat/screens/home.dart:46:96) I/flutter ( 9332): #2
> SliverChildBuilderDelegate.build
> (package:flutter/src/widgets/sliver.dart:449:22) I/flutter ( 9332): #3
> SliverMultiBoxAdaptorElement._build
> (package:flutter/src/widgets/sliver.dart:1130:28) I/flutter ( 9332):
> #4 SliverMultiBoxAdaptorElement.createChild.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1143:55) I/flutter (
> 9332):
> #5 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2626:19) I/flutter (
> 9332): #6 SliverMultiBoxAdaptorElement.createChild
> (package:flutter/src/widgets/sliver.dart:1136:11) I/flutter ( 9332):
> #7 RenderSliverMultiBoxAdaptor._createOrObtainChild.<anonymous closure>
> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:350:23)
> I/flutter ( 9332): #8
> RenderObject.invokeLayoutCallback.<anonymous closure>
> (package:flutter/src/rendering/object.dart:1883:59) I/flutter ( 9332):
> #9 PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:915:15) I/flutter ( 9332):
> #10 RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:1883:14) I/flutter ( 9332):
> #11 RenderSliverMultiBoxAdaptor._createOrObtainChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:339:5)
> I/flutter ( 9332): #12
> RenderSliverMultiBoxAdaptor.insertAndLayoutLeadingChild
> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:455:5)
> I/flutter ( 9332): #13 RenderSliverList.performLayout
> (package:flutter/src/rendering/sliver_list.dart:120:29) I/flutter (
> 9332): #14 RenderObject.layout
> (package:flutter/src/rendering/object.dart:1777:7) I/flutter ( 9332):
> #15 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:507:13) I/flutter (
> 9332): #16 RenderViewport._attemptLayout
> (package:flutter/src/rendering/viewport.dart:1548:12) I/flutter (
> 9332): #17 RenderViewport.performLayout
> (package:flutter/src/rendering/viewport.dart:1457:20) I/flutter (
> 9332): #18 RenderObject._layoutWithoutResize
> (package:flutter/src/rendering/object.dart:1634:7) I/flutter ( 9332):
> #19 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:884:18) I/flutter ( 9332):
> #20 RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:436:19) I/flutter ( 9332):
> #21 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:914:13) I/flutter ( 9332):
> #22 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:302:5) I/flutter ( 9332):
> #23 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1117:15) I/flutter (
> 9332): #29 _invoke (dart:ui/hooks.dart:251:10)
> ler/binding.dart:1055:9) I/flutter ( 9332): #30 _drawFrame
> (dart:ui/hooks.dart:209:3)
> uler/binding.dart:971:5) I/flutter ( 9332): (elided 3 frames from
> dart:async) I/flutter ( 9332):
> ════════════════════════════════════════════════════════════════════════════════════════════════════
> I/flutter ( 9332): Another exception was thrown: RangeError (index):
> Invalid value: Not════════════════════════════════ in inclusive range
> 0..1: 2 in inclusive range 0..1: 2
for(final question in question.data.quiz.info.questions[index])
Text(question.structure.options[0]['text'])
Column(
children: List.generate(
option.length, // Length of the list
(index) => Text(option[index]['text']
) //Display the content of a list in a column