我有一个称为锚的数据列表，它具有指向详细屏幕的链接。每个锚都有分布中心，分布中心是嵌套对象的数组。因此，我能够将每个锚点的ID解析到一个详细的屏幕，而 Oid则 面临一个挑战，即要遍历子项（即锚点的分发中心）。请任何人帮助我，我能够将属于锚的所有值拉到详细屏幕，但是如何在详细屏幕中循环嵌套值是一个问题。嵌套值是下面数组中的DistributionCentres。请任何人可以帮助我进一步学习颤振吗？
json数组：
{ "Anchors": [ { "Oid": 11, "Name": "MAIZE ASSOCIATION OF NIGERIA", "Acronym": "MAAN", "DistributionCentres": [ { "Oid": 11, "Name": "Logo Centre (Zone A)", "Address": "Private Warehouse, Ugba, Logo LGA" }, { "Oid": 12, "Name": "Makurdi Centre (Zone B)", "Address": "Ministry of Agric, Makurdi " }, { "Oid": 13, "Name": "Oturkpo Centre (Zone C)", "Address": "Private Warehouse, Oturkpo" }, { "Oid": 15, "Name": "Borno MAAN centre", "Address": "Bolori Store, Flavour Mill, Behind Vita Foam, Maiduguri" }, { "Oid": 18, "Name": "Bauchi Centre", "Address": "BASPD, Dass Road, Bauchi" } ], "NoOfDistributionCentres": 5 }, { "Oid": 2, "Name": "MAIZE GROWERS, PROCESSORS AND MARKETERS ASSOCIATION OF NIGERIA", "Acronym": "MAGPAMAN", "DistributionCentres": [ { "Oid": 2, "Name": "Guma Centre", "Address": "P 32, 2nd Avenue Federal Housing Estate, N/Bank, Makurdi" }, { "Oid": 3, "Name": "Logo Centre", "Address": "Terhemen Akema Storage Facility, Ugba, Logo LGA" }, { "Oid": 5, "Name": "Oturkpo Centre", "Address": "Grain Store, Lower Benue Okele Project, Otukpo" }, { "Oid": 6, "Name": "Gboko Centre", "Address": "K3 New Road, Opposite former coca cola plant. Solar Schools Street, Gboko" }, { "Oid": 7, "Name": "Gwer East Centre", "Address": "Ahua Shardye's Warehouse, Behind Sylkan Filling Station, Ikpayongo , G/East LGA" }, { "Oid": 8, "Name": "Kwande Centre", "Address": "KM 3, Adagi Road, Adikpo" }, { "Oid": 9, "Name": "Ohimini Centre", "Address": "Ajoga Oglewu, Ohimini" }, { "Oid": 10, "Name": "Oju Centre", "Address": "Behind Town Hall, Ohuhu owo, Oju LGA" } ], "NoOfDistributionCentres": 8 } ], }
锚点页面，其中包含指向详细屏幕的链接：
import 'package:erg_app/AnchorDetails.dart'; import 'package:erg_app/Details.dart'; import 'package:erg_app/StockPage.dart'; import 'package:flutter/material.dart'; import 'package:erg_app/Widgets/nav-drawer.dart'; import 'dart:convert'; import 'package:shared_preferences/shared_preferences.dart'; void main() => runApp(MaterialApp( home: AnchorsPage(), )); class AnchorsPage extends StatefulWidget { @override _MyHomeState createState() => _MyHomeState(); } class _MyHomeState extends State<AnchorsPage> { var user; var userData; List <dynamic> anchors = []; @override void initState() { _getUserAnchor(); super.initState(); } _getUserAnchor() async { SharedPreferences localStorage = await SharedPreferences.getInstance(); var userJson = localStorage.getString('loginRes'); user = json.decode(userJson); setState(() { anchors = user['Anchors']; }); print(anchors); setState(() { userData = anchors; }); } @override Widget build(BuildContext context) { return Scaffold( drawer: NavDrawer(), appBar: AppBar( title: Text('Anchors Details'), iconTheme: IconThemeData(color: Colors.white), backgroundColor: Colors.green, ), body: Container( padding: const EdgeInsets.fromLTRB(10, 30, 10, 10), child: ListView( children: <Widget>[ Row( mainAxisAlignment: MainAxisAlignment.spaceAround, children: <Widget>[ Icon(Icons.card_membership, size: 35, color: Colors.orange[400]), Text( 'Assigned Anchors', style: TextStyle(color: Colors.orange[400], fontSize: 25), ), ], ), ListView.builder( shrinkWrap: true, itemCount: anchors.length, physics: NeverScrollableScrollPhysics(), itemBuilder: (BuildContext context, int i) { return Padding( padding: const EdgeInsets.all(10.0), ////////////// 1st card/////////// child: Card( elevation: 4.0, color: Colors.grey[100], margin: EdgeInsets.only( left: 10, right: 10, top: 20, bottom: 10), shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(10)), child: Container( padding: EdgeInsets.only(left: 15, top: 20, bottom: 10), width: MediaQuery.of(context).size.width, child: Column( crossAxisAlignment: CrossAxisAlignment.start, children: <Widget>[ Row( children: <Widget>[ Padding( padding: const EdgeInsets.all(8.0), child: Container( width: 50.0, height: 50.0, decoration: new BoxDecoration( shape: BoxShape.circle, image: new DecorationImage( fit: BoxFit.cover, image: AssetImage( 'assets/images/user.png')))), ), SizedBox( width: 20, ), Text( anchors[i]['Acronym'], textAlign: TextAlign.center, style: TextStyle( color: Color(0xFF9b9b9b), fontSize: 20, decoration: TextDecoration.none, fontWeight: FontWeight.normal, ), ), ], ), Container(width: 10), Row( children: <Widget>[ Padding( padding: const EdgeInsets.only(left: 10, top: 10), child: Text( 'Allocated Farmers:', textAlign: TextAlign.left, style: TextStyle( color: Color(0xFF9b9b9b), fontSize: 14.0, decoration: TextDecoration.none, fontWeight: FontWeight.normal, ), ), ), Padding( padding: const EdgeInsets.only(left: 70, top: 12), child: Text( anchors[i]['Oid'].toString(), textAlign: TextAlign.left, style: TextStyle( color: Colors.grey[700], fontSize: 14.0, decoration: TextDecoration.none, fontWeight: FontWeight.normal, ), ), ), ], ), Container( height: 20, ), Row( children: <Widget>[ /////////// Buttons ///////////// Padding( padding: const EdgeInsets.all(10.0), child: FlatButton( child: Padding( padding: EdgeInsets.only( top: 8, bottom: 8, left: 10, right: 8), child: Text( 'View Details', textDirection: TextDirection.ltr, style: TextStyle( color: Colors.white, fontSize: 15.0, decoration: TextDecoration.none, fontWeight: FontWeight.normal, ), ), ), color: Colors.blueGrey, shape: new RoundedRectangleBorder( borderRadius: new BorderRadius.circular( 20.0)), onPressed: () { Navigator.push( context, new MaterialPageRoute( builder: (context) => detailsPage(value : anchors))); }, ), ), /////////// End of Buttons ///////////// ], ), ], ), ), ), ); }) ], ), ), ); } }
详细画面：
import 'package:flutter/material.dart'; class detailsPage extends StatefulWidget { dynamic value; detailsPage({Key key, @required this.value}) : super(key: key); @override _detailsPageState createState() => _detailsPageState(value); } class _detailsPageState extends State<detailsPage> { dynamic value; _detailsPageState(this.value); @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text("Anchors Details Page"), iconTheme: IconThemeData(color: Colors.white), backgroundColor: Colors.green, ), // body: Center( // child: Text( // value[1]['Name'].toString(), // ), // ), body: Column( children: <Widget>[ Padding( padding: const EdgeInsets.all(8.0), child: Card( child: Column( children: <Widget>[ Text(value[1]['Name']), Text(value[1]['Oid'].toString()), //Text(value [1]['DistributionCentres']), ], ), ), ), ], ), ); } }
我建议您在这种情况下使用数据类。
import 'package:flutter/material.dart'; List<Anchor> _parseAnchors(Map<String, dynamic> map) { final anchors = <Anchor>[]; for (var anchorMap in map['Anchors']) { final anchor = Anchor.fromMap(anchorMap); anchors.add(anchor); } return anchors; } class Anchor { final int oId; final String name; final String acronym; final List<DistributionCenter> distributionCenters; const Anchor({ @required this.oId, @required this.name, @required this.acronym, @required this.distributionCenters, }); factory Anchor.fromMap(Map<String, dynamic> map) { final distributionCenters = <DistributionCenter>[]; for (var distribution in map['DistributionCentres']) { final distributionCenter = DistributionCenter.fromMap(distribution); distributionCenters.add(distributionCenter); } return Anchor( oId: map['Oid'] as int, name: map['Name'] as String, acronym: map['Acronym'] as String, distributionCenters: distributionCenters, ); } } class DistributionCenter { final int id; final String name; final String address; const DistributionCenter({ @required this.id, @required this.name, @required this.address, }); factory DistributionCenter.fromMap(Map<String, dynamic> map) { return DistributionCenter( id: map['Oid'] as int, name: map['Name'] as String, address: map['Address'] as String, ); } } class AnchorPage extends StatelessWidget { // details page final Anchor anchor; @override const AnchorPage({Key key, @required this.anchor}) : super(key: key); Widget build(BuildContext context) { return Scaffold( body: Container( child: Text(anchor.name), ), ); } } class AnchorsPage extends StatefulWidget { const AnchorsPage({Key key}) : super(key: key); @override _AnchorsPageState createState() => _AnchorsPageState(); } class _AnchorsPageState extends State<AnchorsPage> { static const anchorsMap = { "Anchors": [ { "Oid": 11, "Name": "MAIZE ASSOCIATION OF NIGERIA", "Acronym": "MAAN", "DistributionCentres": [ { "Oid": 11, "Name": "Logo Centre (Zone A)", "Address": "Private Warehouse, Ugba, Logo LGA" }, { "Oid": 12, "Name": "Makurdi Centre (Zone B)", "Address": "Ministry of Agric, Makurdi " }, { "Oid": 13, "Name": "Oturkpo Centre (Zone C)", "Address": "Private Warehouse, Oturkpo" }, { "Oid": 15, "Name": "Borno MAAN centre", "Address": "Bolori Store, Flavour Mill, Behind Vita Foam, Maiduguri" }, { "Oid": 18, "Name": "Bauchi Centre", "Address": "BASPD, Dass Road, Bauchi" } ], "NoOfDistributionCentres": 5 }, { "Oid": 2, "Name": "MAIZE GROWERS, PROCESSORS AND MARKETERS ASSOCIATION OF NIGERIA", "Acronym": "MAGPAMAN", "DistributionCentres": [ { "Oid": 2, "Name": "Guma Centre", "Address": "P 32, 2nd Avenue Federal Housing Estate, N/Bank, Makurdi" }, { "Oid": 3, "Name": "Logo Centre", "Address": "Terhemen Akema Storage Facility, Ugba, Logo LGA" }, { "Oid": 5, "Name": "Oturkpo Centre", "Address": "Grain Store, Lower Benue Okele Project, Otukpo" }, { "Oid": 6, "Name": "Gboko Centre", "Address": "K3 New Road, Opposite former coca cola plant. Solar Schools Street, Gboko" }, { "Oid": 7, "Name": "Gwer East Centre", "Address": "Ahua Shardye's Warehouse, Behind Sylkan Filling Station, Ikpayongo , G/East LGA" }, { "Oid": 8, "Name": "Kwande Centre", "Address": "KM 3, Adagi Road, Adikpo" }, { "Oid": 9, "Name": "Ohimini Centre", "Address": "Ajoga Oglewu, Ohimini" }, { "Oid": 10, "Name": "Oju Centre", "Address": "Behind Town Hall, Ohuhu owo, Oju LGA" } ], "NoOfDistributionCentres": 8 } ], }; final _anchors = <Anchor>[]; @override Widget build(BuildContext context) { // now you can use the anchors list here return Scaffold( body: ListView.builder( itemCount: _anchors.length, itemBuilder: (context, index) { final anchor = _anchors[index]; return ListTile( title: Text(anchor.name), subtitle: Text(anchor.acronym), trailing: Text(anchor.distributionCenters?.length?.toString()), onTap: () { Navigator.push( context, MaterialPageRoute( builder: (context) => AnchorPage(anchor: anchor), ), ); }, ); }, ), ); } @override void initState() { super.initState(); final anchors = _parseAnchors(anchorsMap); _anchors.addAll(anchors); } }
