Flutter 如何在sqflite列的逗号分隔值的颤振中进行下拉
我想在颤振下拉哪个值来自sqflite数据库。样本值为Flutter 如何在sqflite列的逗号分隔值的颤振中进行下拉,flutter,dart,dropdown,sqflite,Flutter,Dart,Dropdown,Sqflite,我想在颤振下拉哪个值来自sqflite数据库。样本值为 { "id": 5, "name": "New", "stages": "{\"Lead in\":false,\"Contacted\":false,\"Demo Presented\":false,\"Proposal Sent\":false,\"t4eg4ehhhe4h\":false,\"Extra Features Discussed\":false
{
"id": 5,
"name": "New",
"stages": "{\"Lead in\":false,\"Contacted\":false,\"Demo Presented\":false,\"Proposal Sent\":false,\"t4eg4ehhhe4h\":false,\"Extra Features Discussed\":false,\"Negotiation\":false,\"Closure\":false}",
"created_at": "2019-05-03 17:49:05",
"updated_at": "2019-06-06 16:16:04",
"deleted_at": null
},
FutureBuilder(
future: pipelineHelper.getPipeStage(pipelineId),
builder: (BuildContext context,
AsyncSnapshot<List<Pipeline>>
snapshot) {
if (!snapshot.hasData)
return CircularProgressIndicator();
return DropdownButton(
items: snapshot.data
.map((stageList) => DropdownMenuItem<Pipeline>(
value: stageList, child: Text(stageList.stages),))
.toList(),
onChanged: (actList) {
setState(() {
stageName = actList.title;
debugPrint('stage selected');
});
},
isExpanded: true,
);
})
如果我明白你的意思
在代码pipelineHelper.getPipeStage（pipelineId）中，只返回一条管道记录
因此，AsyncSnapshot列表管道应更改为AsyncSnapshot管道
在项目中，可以使用拆分来拆分逗号并返回DropdownMenuItem
items: snapshot.data.stage
.split(', ')
import 'package:flutter/material.dart';
import 'dart:convert';
import 'package:http/http.dart' as http;
void main() => runApp(MyApp());
// To parse this JSON data, do
//
// final stages = stagesFromJson(jsonString);
List<Pipeline> stagesFromJson(String str) =>
List<Pipeline>.from(json.decode(str).map((x) => Pipeline.fromJson(x)));
String stagesToJson(List<Pipeline> data) =>
json.encode(List<dynamic>.from(data.map((x) => x.toJson())));
class Pipeline {
String pipelineId;
String stage;
Pipeline({
this.pipelineId,
this.stage,
});
factory Pipeline.fromJson(Map<String, dynamic> json) => Pipeline(
pipelineId: json["pipelineId"],
stage: json["stage"],
);
Map<String, dynamic> toJson() => {
"pipelineId": pipelineId,
"stage": stage,
};
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: JsonApiDropdown(),
);
}
}
class JsonApiDropdown extends StatefulWidget {
@override
JsonApiDropdownState createState() {
return new JsonApiDropdownState();
}
}
class JsonApiDropdownState extends State<JsonApiDropdown> {
String _currentSelection;
final String uri = 'https://jsonplaceholder.typicode.com/users';
Future<Pipeline> _fetchstage() async {
String jsonString =
'[ { "pipelineId": "CDG0008", "stage": "stage1, stage2, stage3" }, { "pipelineId": "CDG0004", "stage": "Ceo - Chief Executive Officer" } ]';
final stages = stagesFromJson(jsonString);
return stages[0];
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Fetching data from JSON - DropdownButton'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
mainAxisSize: MainAxisSize.max,
children: <Widget>[
FutureBuilder<Pipeline>(
future: _fetchstage(),
builder:
(BuildContext context, AsyncSnapshot<Pipeline> snapshot) {
if (!snapshot.hasData) return CircularProgressIndicator();
return DropdownButton<String>(
items: snapshot.data.stage
.split(', ')
.map((data) => DropdownMenuItem<String>(
child: Text(data),
value: data,
))
.toList(),
onChanged: (String value) {
setState(() {
_currentSelection = value;
});
},
isExpanded: false,
//value: _currentUser,
hint: Text('Select User'),
);
}),
SizedBox(height: 20.0),
_currentSelection != null
? Text("selection : " + _currentSelection)
: Text("No selected"),
],
),
),
);
}
}
导入“包装：颤振/材料.省道”；
导入“dart:convert”；
将“package:http/http.dart”导入为http；
void main（）=>runApp（MyApp（））；
//要解析此JSON数据，请执行以下操作
//
//最终阶段=stagesFromJson（jsonString）；
List stagesFromJson（字符串str）=>
List.from（json.decode（str.map）（x）=>Pipeline.fromJson（x））；
字符串stagesToJson（列表数据）=>
encode（List.from（data.map（（x）=>x.toJson（））；
类管道{
字符串管道ID；
弦乐台；
管道({
这是pipelineId，
这个阶段,，
});
工厂管道.fromJson（映射json）=>管道(
pipelineId:json[“pipelineId”]，
stage:json[“stage”]，
);
映射到JSON（）=>{
“管道ID”：管道ID，
“舞台”：舞台，
};
}
类MyApp扩展了无状态小部件{
//此小部件是应用程序的根。
@凌驾
小部件构建（构建上下文）{
返回材料PP(
标题：“颤振演示”，
主题：主题数据(
//这是应用程序的主题。
//
//尝试使用“flutter run”运行应用程序。您将看到
//应用程序有一个蓝色工具栏。然后，在不退出应用程序的情况下，重试
//将下面的primarySwatch更改为Colors.green，然后调用
//“热重新加载”（在运行“颤振运行”的控制台中按“r”，
//或者只需将更改保存到颤振IDE中的“热重新加载”。
//请注意，计数器没有重置回零；应用程序
//未重新启动。
主样本：颜色。蓝色，
),
主页：JsonApiDropdown（），
);
}
}
类JsonApiDropdown扩展了StatefulWidget{
@凌驾
JsonApiDropdownState createState（）{
返回新的JsonApiDropdownState（）；
}
}
类JsonApiDropdownState扩展状态{
字符串currentSelection；
最后一个字符串uri=https://jsonplaceholder.typicode.com/users';
Future _fetchstage（）异步{
字符串jsonString=
“[{”pipelineId:“CDG0008”，“stage:“stage1，stage2，stage3”}，{”pipelineId:“CDG0004”，“stage:“Ceo-首席执行官”}”；
最终阶段=stagesFromJson（jsonString）；
返回阶段[0]；
}
@凌驾
小部件构建（构建上下文）{
返回脚手架(
appBar:appBar(
标题：Text（'fetchingdatafromsjson-DropdownButton'），
),
正文：中(
子：列(
mainAxisAlignment:mainAxisAlignment.center，
mainAxisSize:mainAxisSize.max，
儿童：[
未来建设者(
未来：_fetchstage（），
建设者：
（BuildContext上下文，异步快照）{
如果（！snapshot.hasData）返回CircularProgressIndicator（）；
返回下拉按钮(
项目：snapshot.data.stage
.split（“，”）
.map（（数据）=>下拉菜单项(
子项：文本（数据），
价值：数据，
))
.toList（），
onChanged:（字符串值）{
设置状态（）{
_当前选择=值；
});
},
isExpanded:错，
//值：_currentUser，
提示：文本（“选择用户”），
);
}),
尺寸箱（高度：20.0），
_currentSelection！=null
文本（“选择：”+\u当前选择）
：文本（“未选择”），
],
),
),
);
}
}
我在添加snapshot.data.stage.split（“，”）时遇到此错误。没有为类“List”定义getter“stages”。我们有不同的字段名，我使用stage和您的is stages。它们完全是两个不同的问题。我建议在一个新的问题上贴一个帖子。对某人来说，搜索和帮助会更容易。谢谢。谢谢你的帮助。如果你有兴趣回答我的新问题，你可以访问
items: snapshot.data.stage
.split(', ')
import 'package:flutter/material.dart';
import 'dart:convert';
import 'package:http/http.dart' as http;
void main() => runApp(MyApp());
// To parse this JSON data, do
//
// final stages = stagesFromJson(jsonString);
List<Pipeline> stagesFromJson(String str) =>
List<Pipeline>.from(json.decode(str).map((x) => Pipeline.fromJson(x)));
String stagesToJson(List<Pipeline> data) =>
json.encode(List<dynamic>.from(data.map((x) => x.toJson())));
class Pipeline {
String pipelineId;
String stage;
Pipeline({
this.pipelineId,
this.stage,
});
factory Pipeline.fromJson(Map<String, dynamic> json) => Pipeline(
pipelineId: json["pipelineId"],
stage: json["stage"],
);
Map<String, dynamic> toJson() => {
"pipelineId": pipelineId,
"stage": stage,
};
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: JsonApiDropdown(),
);
}
}
class JsonApiDropdown extends StatefulWidget {
@override
JsonApiDropdownState createState() {
return new JsonApiDropdownState();
}
}
class JsonApiDropdownState extends State<JsonApiDropdown> {
String _currentSelection;
final String uri = 'https://jsonplaceholder.typicode.com/users';
Future<Pipeline> _fetchstage() async {
String jsonString =
'[ { "pipelineId": "CDG0008", "stage": "stage1, stage2, stage3" }, { "pipelineId": "CDG0004", "stage": "Ceo - Chief Executive Officer" } ]';
final stages = stagesFromJson(jsonString);
return stages[0];
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Fetching data from JSON - DropdownButton'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
mainAxisSize: MainAxisSize.max,
children: <Widget>[
FutureBuilder<Pipeline>(
future: _fetchstage(),
builder:
(BuildContext context, AsyncSnapshot<Pipeline> snapshot) {
if (!snapshot.hasData) return CircularProgressIndicator();
return DropdownButton<String>(
items: snapshot.data.stage
.split(', ')
.map((data) => DropdownMenuItem<String>(
child: Text(data),
value: data,
))
.toList(),
onChanged: (String value) {
setState(() {
_currentSelection = value;
});
},
isExpanded: false,
//value: _currentUser,
hint: Text('Select User'),
);
}),
SizedBox(height: 20.0),
_currentSelection != null
? Text("selection : " + _currentSelection)
: Text("No selected"),
],
),
),
);
}
}