Flutter JSON数据可视化插件json_explorer的使用
Flutter JSON数据可视化插件json_explorer的使用
JSON Explorer
一个用于渲染、查看和与JSON进行交互的Flutter小部件。它还包括了互动搜索功能。
维护的分支版本,包含修复和改进:
功能
- 展开和折叠类和数组节点。
- 带有高亮的动态搜索。
- 可配置的主题和交互。
- 可配置的数据显示格式。
- 缩进指南。
使用
要显示的数据由存储管理,即JsonExplorerStore
。
为了使用此包的所有功能,你需要在[Provider](https://pub.dev/packages/provider)
中注册它。
final JsonExplorerStore store = JsonExplorerStore();
// ...
ChangeNotifierProvider.value(
value: store,
child:
// ...
加载JSON对象时,可以使用JsonExplorerStore.buildNodes
方法:
store.buildNodes(json.decode(myJson));
要显示数据浏览器,可以使用JsonExplorer
小部件。唯一需要的参数是一组节点模型,可以从JsonExplorerStore
中获取解码后的JSON。
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: SafeArea(
minimum: const EdgeInsets.all(16),
child: ChangeNotifierProvider.value(
value: store,
child: Consumer<JsonExplorerStore>(
builder: (context, state, child) => JsonExplorer(
nodes: state.displayNodes,
),
),
),
),
);
}
这将使用默认主题显示解码后的JSON。
有关如何自定义JsonExplorer
小部件的外观和感觉,请参阅/example
应用程序。
更改外观和感觉
主题
要更改字体和颜色,可以使用JsonExplorerTheme
:
JsonExplorer(
nodes: state.displayNodes,
theme: JsonExplorerTheme(
rootKeyTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
fontWeight: FontWeight.bold,
fontSize: 16,
),
propertyKeyTextStyle: GoogleFonts.inconsolata(
color: Colors.black.withOpacity(0.7),
fontWeight: FontWeight.bold,
fontSize: 16,
),
keySearchHighlightTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
backgroundColor: const Color(0xFFFFEDAD),
fontWeight: FontWeight.bold,
fontSize: 16,
),
focusedKeySearchHighlightTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
backgroundColor: const Color(0xFFF29D0B),
fontWeight: FontWeight.bold,
fontSize: 16,
),
valueTextStyle: GoogleFonts.inconsolata(
color: const Color(0xFFCA442C),
fontSize: 16,
),
valueSearchHighlightTextStyle: GoogleFonts.inconsolata(
color: const Color(0xFFCA442C),
backgroundColor: const Color(0xFFFFEDAD),
fontWeight: FontWeight.bold,
fontSize: 16,
),
focusedValueSearchHighlightTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
backgroundColor: const Color(0xFFF29D0B),
fontWeight: FontWeight.bold,
fontSize: 16,
),
indentationLineColor: const Color(0xFFE1E1E1),
highlightColor: const Color(0xFFF1F1F1),
),
)
格式化器
除了更改主题外,还可以通过Formatter
方法更改键和值如何被转换为字符串。
默认情况下,显示JSON属性名称的方式为key:
,但可以通过格式化器进行更改:
JsonExplorer(
nodes: state.displayNodes,
propertyNameFormatter: (name) => '$name ->',
)
现在所有属性键都显示为key ->
。
动态更改基于值的属性样式
可以使用valueStyleBuilder
参数动态更改基于值的属性样式。它期望一个函数,该函数接收属性的dynamic value
和当前的style
,并返回一个PropertyOverrides
。
例如,为包含链接的值添加交互:
JsonExplorer(
nodes: state.displayNodes,
valueStyleBuilder: (value, style) {
final isUrl = _valueIsUrl(value);
return PropertyOverrides(
style: isUrl
? style.copyWith(
decoration: TextDecoration.underline,
)
: style,
onTap: isUrl ? () => _launchUrl(value) : null,
);
},
)
或者遵循相同的原则,根据特定值类型更改其外观:
JsonExplorer(
nodes: state.displayNodes,
valueStyleBuilder: (value, style) {
if (value is num) {
return PropertyOverrides(
style: style.copyWith(
color: Colors.blue,
),
);
}
return PropertyOverrides(
style: style,
);
},
)
自定义小部件组件
collapsableToggleBuilder
允许更改根节点上显示的展开和折叠按钮。例如,使用简单的隐式动画小部件:
JsonExplorer(
nodes: state.displayNodes,
collapsableToggleBuilder: (context, node) =>
AnimatedRotation(
turns: node.isCollapsed ? -0.25 : 0,
duration: const Duration(milliseconds: 300),
child: const Icon(Icons.arrow_drop_down),
),
)
rootInformationBuilder
构建一个在类和数组根节点上显示的小部件。例如,这可以用来显示其子节点的一些信息:
JsonExplorer(
nodes: state.displayNodes,
rootInformationBuilder: (context, node) => Text(
node.isClass
? '{${(node.childrenCount)}}'
: '[${node.childrenCount}]',
),
)
trailingBuilder
构建每个节点的尾部小部件。NodeViewModelState
参数允许小部件对某些节点属性做出反应。例如,构建一个仅在节点当前聚焦时出现的小部件:
JsonExplorer(
nodes: state.displayNodes,
trailingBuilder: (context, node) => node.isFocused
? Text("I'm focused :)")
: const SizedBox(),
)
搜索
JsonExplorerStore
提供了使用search
方法的搜索功能。JsonExplorer
小部件已经对这些状态变化作出响应,并突出显示搜索结果。请参阅JsonExplorerTheme
以更改搜索结果的外观。
可以使用focusPreviousSearchResult
和focusNextSearchResult
方法更改当前焦点的结果。
以下是一个简单的搜索栏示例,可以在example
文件夹中找到完整的示例:
Row(
children: [
Expanded(
child: TextField(
controller: searchController,
onChanged: (term) => jsonExplorerStore.search(term),
maxLines: 1,
decoration: const InputDecoration(
hintText: 'Search',
),
),
),
const SizedBox(
width: 8,
),
IconButton(
onPressed: jsonExplorerStore.focusPreviousSearchResult,
icon: const Icon(Icons.arrow_drop_up),
),
IconButton(
onPressed: jsonExplorerStore.focusNextSearchResult,
icon: const Icon(Icons.arrow_drop_down),
),
],
),
自定义滚动小部件
可以通过使用JsonAttribute
小部件来显示每个节点,从而实现自己的滚动。
一个简单的ListView.builder
看起来像这样:
ListView.builder(
itemCount: state.displayNodes.length,
itemBuilder: (context, index) => JsonAttribute(
node: state.displayNodes.elementAt(index),
theme: JsonExplorerTheme.defaultTheme,
),
),
示例代码
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:http/http.dart' as http;
import 'package:json_explorer/json_explorer.dart';
import 'package:provider/provider.dart';
import 'package:scrollable_positioned_list/scrollable_positioned_list.dart';
import 'package:url_launcher/url_launcher_string.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
[@override](/user/override)
Widget build(BuildContext context) {
return MaterialApp(
title: 'Json Explorer',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(),
);
}
}
class MyHomePage extends StatelessWidget {
const MyHomePage({Key? key}) : super(key: key);
[@override](/user/override)
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Test Json Explorer'),
),
body: ListView(
padding: const EdgeInsets.all(16),
children: [
Text(
'Small JSON',
style: Theme.of(context).textTheme.bodyMedium,
),
const _OpenJsonButton(
title: 'ISS current location',
url: 'http://api.open-notify.org/iss-now.json',
padding: EdgeInsets.symmetric(vertical: 8.0),
),
const _OpenJsonButton(
title: 'Country List',
url: 'https://api.foss42.com/country/codes',
padding: EdgeInsets.symmetric(vertical: 8.0),
),
Text(
'Medium JSON',
style: Theme.of(context).textTheme.bodyMedium,
),
const _OpenJsonButton(
title: 'Nobel prizes country',
url: 'http://api.nobelprize.org/v1/country.json',
padding: EdgeInsets.symmetric(vertical: 8.0),
),
const _OpenJsonButton(
title: 'Australia ABC Local Stations',
url:
'https://data.gov.au/geoserver/abc-local-stations/wfs?request=GetFeature&typeName=ckan_d534c0e9_a9bf_487b_ac8f_b7877a09d162&outputFormat=json',
),
Text(
'Large JSON',
style: Theme.of(context).textTheme.bodyMedium,
),
const _OpenJsonButton(
title: 'Pokémon',
url: 'https://pokeapi.co/api/v2/pokemon/?offset=0&limit=2000',
padding: EdgeInsets.symmetric(vertical: 8.0),
),
const _OpenJsonButton(
title: 'Earth Meteorite Landings',
url: 'https://data.nasa.gov/resource/y77d-th95.json',
),
const _OpenJsonButton(
title: 'Reddit r/all',
url: 'https://www.reddit.com/r/all.json',
),
Text(
'Exploding JSON',
style: Theme.of(context).textTheme.bodyMedium,
),
const _OpenJsonButton(
title: '25MB GitHub Json',
url:
'https://raw.githubusercontent.com/json-iterator/test-data/master/large-file.json',
padding: EdgeInsets.only(top: 8.0, bottom: 32.0),
),
Text(
'More datasets at https://awesomeopensource.com/project/jdorfman/awesome-json-datasets',
style: Theme.of(context).textTheme.bodySmall,
),
],
),
);
}
}
class JsonExplorerPage extends StatefulWidget {
final String jsonUrl;
final String title;
const JsonExplorerPage({
Key? key,
required this.jsonUrl,
required this.title,
}) : super(key: key);
[@override](/user/override)
_JsonExplorerPageState createState() => _JsonExplorerPageState();
}
class _JsonExplorerPageState extends State<JsonExplorerPage> {
final searchController = TextEditingController();
final itemScrollController = ItemScrollController();
final JsonExplorerStore store = JsonExplorerStore();
[@override](/user/override)
void initState() {
_loadJsonDataFrom(widget.jsonUrl);
super.initState();
}
[@override](/user/override)
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: SafeArea(
minimum: const EdgeInsets.all(16),
child: ChangeNotifierProvider.value(
value: store,
child: Consumer<JsonExplorerStore>(
builder: (context, state, child) => Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
Expanded(
child: TextField(
controller: searchController,
/// Delegates the search to [JsonExplorerStore] when
/// the text field changes.
onChanged: (term) => state.search(term),
decoration: const InputDecoration(
hintText: 'Search',
),
),
),
const SizedBox(
width: 8,
),
if (state.searchResults.isNotEmpty)
Text(_searchFocusText()),
if (state.searchResults.isNotEmpty)
IconButton(
onPressed: () {
store.focusPreviousSearchResult();
_scrollToSearchMatch();
},
icon: const Icon(Icons.arrow_drop_up),
),
if (state.searchResults.isNotEmpty)
IconButton(
onPressed: () {
store.focusNextSearchResult();
_scrollToSearchMatch();
},
icon: const Icon(Icons.arrow_drop_down),
),
],
),
const SizedBox(
height: 16.0,
),
Row(
children: [
TextButton(
onPressed: state.areAllExpanded() ? null : state.expandAll,
child: const Text('Expand All'),
),
const SizedBox(
width: 8.0,
),
TextButton(
onPressed: state.areAllCollapsed() ? null : state.collapseAll,
child: const Text('Collapse All'),
),
],
),
const SizedBox(
height: 16.0,
),
Expanded(
child: JsonExplorer(
nodes: state.displayNodes,
itemScrollController: itemScrollController,
itemSpacing: 4,
maxRootNodeWidth: 200,
/// Builds a widget after each root node displaying the
/// number of children nodes that it has. Displays `{x}`
/// if it is a class or `[x]` in case of arrays.
rootInformationBuilder: (context, node) => DecoratedBox(
decoration: const BoxDecoration(
color: Color(0x80E1E1E1),
borderRadius: BorderRadius.all(Radius.circular(2)),
),
child: Padding(
padding: const EdgeInsets.symmetric(
horizontal: 4,
vertical: 2,
),
child: Text(
node.isClass
? '{${node.childrenCount}}'
: '[${node.childrenCount}]',
style: GoogleFonts.inconsolata(
fontSize: 12,
color: const Color(0xFF6F6F6F),
),
),
),
),
/// Build an animated collapse/expand indicator. Implicitly
/// animates the indicator when
/// [NodeViewModelState.isCollapsed] changes.
collapsableToggleBuilder: (context, node) =>
AnimatedRotation(
turns: node.isCollapsed ? -0.25 : 0,
duration: const Duration(milliseconds: 300),
child: const Icon(Icons.arrow_drop_down),
),
/// Builds a trailing widget that copies the node key: value
///
/// Uses [NodeViewModelState.isFocused] to display the
/// widget only in focused widgets.
trailingBuilder: (context, node) => node.isFocused
? IconButton(
padding: EdgeInsets.zero,
constraints: const BoxConstraints(maxHeight: 18),
icon: const Icon(
Icons.copy,
size: 18,
),
onPressed: () => _printNode(node),
)
: const SizedBox(),
/// Creates a custom format for classes and array names.
rootNameFormatter: (dynamic name) => '$name',
/// Dynamically changes the property value style and
/// interaction when an URL is detected.
valueStyleBuilder: (dynamic value, style) {
final isUrl = _valueIsUrl(value);
return PropertyOverrides(
style: isUrl
? style.copyWith(
decoration: TextDecoration.underline,
)
: style,
onTap: isUrl ? () => _launchUrl(value as String) : null,
);
},
/// Theme definitions of the json explorer
theme: JsonExplorerTheme(
rootKeyTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
fontWeight: FontWeight.bold,
fontSize: 16,
),
propertyKeyTextStyle: GoogleFonts.inconsolata(
color: Colors.black.withOpacity(0.7),
fontWeight: FontWeight.bold,
fontSize: 16,
),
keySearchHighlightTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
backgroundColor: const Color(0xFFFFEDAD),
fontWeight: FontWeight.bold,
fontSize: 16,
),
focusedKeySearchHighlightTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
backgroundColor: const Color(0xFFF29D0B),
fontWeight: FontWeight.bold,
fontSize: 16,
),
valueTextStyle: GoogleFonts.inconsolata(
color: const Color(0xFFCA442C),
fontSize: 16,
),
valueSearchHighlightTextStyle: GoogleFonts.inconsolata(
color: const Color(0xFFCA442C),
backgroundColor: const Color(0xFFFFEDAD),
fontWeight: FontWeight.bold,
fontSize: 16,
),
focusedValueSearchHighlightTextStyle: GoogleFonts.inconsolata(
color: Colors.black,
backgroundColor: const Color(0xFFF29D0B),
fontWeight: FontWeight.bold,
fontSize: 16,
),
indentationLineColor: const Color(0xFFE1E1E1),
highlightColor: const Color(0xFFF1F1F1),
),
),
),
],
),
),
),
),
);
}
String _searchFocusText() =>
'${store.focusedSearchResultIndex + 1} of ${store.searchResults.length}';
Future _loadJsonDataFrom(String url) async {
debugPrint('Calling Json API');
final data = await http.read(Uri.parse(url));
debugPrint('Done!');
final dynamic decoded = json.decode(data);
store.buildNodes(decoded, areAllCollapsed: true);
}
void _printNode(NodeViewModelState node) {
if (node.isRoot) {
final value = node.isClass ? 'class' : 'array';
debugPrint('${node.key}: $value');
return;
}
debugPrint('${node.key}: ${node.value}');
}
void _scrollToSearchMatch() {
final index = store.displayNodes.indexOf(store.focusedSearchResult.node);
if (index != -1) {
itemScrollController.scrollTo(
index: index,
duration: const Duration(milliseconds: 300),
curve: Curves.easeInOutCubic,
);
}
}
bool _valueIsUrl(dynamic value) {
if (value is String) {
return Uri.tryParse(value)?.hasAbsolutePath ?? false;
}
return false;
}
Future _launchUrl(String url) {
return launchUrlString(url);
}
[@override](/user/override)
void dispose() {
searchController.dispose();
super.dispose();
}
}
/// A button that navigates to the data explorer page on pressed.
class _OpenJsonButton extends StatelessWidget {
final String url;
final String title;
final EdgeInsets padding;
const _OpenJsonButton({
Key? key,
required this.url,
required this.title,
this.padding = const EdgeInsets.only(bottom: 8.0),
}) : super(key: key);
[@override](/user/override)
Widget build(BuildContext context) => Padding(
padding: padding,
child: ElevatedButton(
child: Text(title),
onPressed: () => Navigator.of(context).push<MaterialPageRoute>(
MaterialPageRoute(
builder: (ctx) => JsonExplorerPage(
jsonUrl: url,
title: title,
),
),
),
),
);
}
更多关于Flutter JSON数据可视化插件json_explorer的使用的实战教程也可以访问 https://www.itying.com/category-92-b0.html
更多关于Flutter JSON数据可视化插件json_explorer的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
在Flutter中,json_explorer
是一个强大的插件,用于可视化和编辑 JSON 数据。以下是一个示例,展示了如何在 Flutter 应用中使用 json_explorer
插件。
首先,确保你的 pubspec.yaml
文件中包含了 json_explorer
依赖项:
dependencies:
flutter:
sdk: flutter
json_explorer: ^最新版本号 # 请替换为实际的最新版本号
然后,运行 flutter pub get
来获取依赖项。
接下来,在你的 Dart 文件中,你可以按照以下方式使用 json_explorer
:
import 'package:flutter/material.dart';
import 'package:json_explorer/json_explorer.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter JSON Explorer Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
// 示例 JSON 数据
final String jsonData = '''
{
"name": "John Doe",
"age": 30,
"isEmployed": true,
"skills": ["Flutter", "Dart", "JSON"],
"address": {
"street": "123 Main St",
"city": "Anytown",
"country": "USA"
}
}
''';
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('JSON Explorer Demo'),
),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: JsonExplorer(
json: jsonData,
readOnly: false, // 设置为 true 以禁用编辑
expanded: true, // 初始时是否展开所有节点
onEdit: (String newJson) {
// 用户编辑 JSON 后的回调
setState(() {
// 这里你可以处理新的 JSON 数据,比如保存到某个变量或进行其他操作
print("Updated JSON: $newJson");
});
},
),
),
);
}
}
在这个示例中:
- 我们定义了一个包含示例 JSON 数据的字符串
jsonData
。 - 在
MyHomePage
的build
方法中,我们使用JsonExplorer
小部件来显示和编辑这个 JSON 数据。 readOnly
参数设置为false
,允许用户编辑 JSON 数据。如果设置为true
,则用户将无法编辑数据。expanded
参数设置为true
,表示在初始加载时展开所有节点。onEdit
回调在 JSON 数据被编辑后触发,你可以在这个回调中处理新的 JSON 数据。
运行这个示例应用,你将看到一个可交互的 JSON 编辑器,你可以在其中浏览和编辑 JSON 数据。