颤振动态扩展 | 颤振动态扩展

本文介绍了颤振动态扩展的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

正在寻找有关动态构建expandTile列表的指导.我有一个成功的Listview，它是通过json API动态构建的，但是找不到有关构建expandTile的任何示例.我有1个api调用，可以带回顶层，而每个顶层都有另一个调用，可以带回扩展列表.有人举这个例子吗?我找到了静态示例，但不清楚如何使它动态.

Looking for some guidance on building expansionTile list dynamically. I have a successful Listview built dynamically from json API, but can not find any examples on building the expansionTile. I have 1 api call that brings back the top level and another call for each top level to bring back the expansion list. Anyone have an example of this? I have found the static example but is not clear how to how to make it dynamic.

这是我想出的一些代码.我可以看到Tile标题部分，并且可以看到图块主体中包含json，但无法弄清楚如何在主体中获取列表标题的正确名称，我没有尝试将其设置为可用.有什么想法吗?

Here is some code I came up with. I can see the Tile title portion and can see the json come in for the tile body, but can not figure out how to get the correct name of the list title in the body, nothing I try to set it to works. Any ideas?

import 'dart:async';
import 'package:intl/intl.dart';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
//import 'package:shared_preferences/shared_preferences.dart';
import 'package:http/http.dart' as http;
//import 'package:cswauthapp/models.dart';
import 'package:flutter/foundation.dart';
import 'dart:convert';

var jsonCodec = const JsonCodec();
List<Exp> myReasonList;
List myDCList;
int mycount = 0;

void main() {
  runApp(new MyApp());

}



class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'ExpansionTile Test',
      home: new MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  @override
  void initState() {
    super.initState();

    _getData();
    //_getSpecialty();
  }

  _getData() async {
    var _url = 'http://$baseurl:8080/support/dc/1';

    var http = createHttpClient();
    var response = await http.get(_url);

    var dc = await jsonCodec.decode(response.body);
    myDCList = await dc.toList();



    print('DC: '+myDCList.toString());

    if (mounted) {
      setState(() {
        //_dataReceived = true;
        mycount = myDCList.length;
      });
    }

  }

  Future _getChildren(int did) async {

    var _url2 = 'http://174.138.61.246:8080/support/dcreasons/$did';
    var http = createHttpClient();
    var response = await http.get(_url2);
    var reasons = await jsonCodec.decode(response.body);
    myReasonList = await reasons.toList();
    print('REASONS: '+ myReasonList.toString());


    return myReasonList;
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('ExpansionTile Test'),
      ),
      body: new ListView.builder(
        itemBuilder: _itemBuilder,
        itemCount: mycount,
      ),
    );
  }

  Widget _itemBuilder(BuildContext context, int index) {
    Exp exp = getExp(index);
    return new ListChild(exp: exp,);
  }

  Exp getExp(int index) {
    return new Exp(
      myDCList[index]['dname'],
      _getChildren(myDCList[index]['did']),
    );
    //return new Specialties.fromMap(mylist[index]);

  }
}

class Exp {
  Exp(this.title, [this.children]);
  final String title;
  final Future<List<Exp>> children;
}


class ListChild extends StatefulWidget {
  ListChild({Key key, this.exp}) : super(key: key);

  final Exp exp;
  @override
  State createState() => new ListChildState();
}

class ListChildState extends State<ListChild> {
  //PageStorageKey<ListChildState> _key = new PageStorageKey(ListChild);
  @override
  Widget build(BuildContext context) {
    return new ExpansionTile(
      key: new PageStorageKey(ListChild),
      title: new Text(widget.exp.title),
      children: <Widget>[
        new Text(widget.exp.children.title),
      ],
    );
  }
}

推荐答案

对您的评论和问题的编辑，我自由地写了一个可行的示例.随时编辑或评论.希望这就是您想要实现的目标.

Reacting to you comment and edit of the question I took the liberty to write a working example. Feel free to edit or comment. I hope, this is what you wanted to achieve.

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';

void main() {
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'ExpansionTile Test',
      home: new MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Future<http.Response> _responseFuture;

  @override
  void initState() {
    super.initState();
    _responseFuture = http.get('http://174.138.61.246:8080/support/dc/1');
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('ExpansionTile Test'),
      ),
      body: new FutureBuilder(
        future: _responseFuture,
        builder: (BuildContext context, AsyncSnapshot<http.Response> response) {
          if (!response.hasData) {
            return const Center(
              child: const Text('Loading...'),
            );
          } else if (response.data.statusCode != 200) {
            return const Center(
              child: const Text('Error loading data'),
            );
          } else {
            List<dynamic> json = JSON.decode(response.data.body);
            return new MyExpansionTileList(json);
          }
        },
      ),
    );
  }
}

class MyExpansionTileList extends StatelessWidget {
  final List<dynamic> elementList;

  MyExpansionTileList(this.elementList);

  List<Widget> _getChildren() {
    List<Widget> children = [];
    elementList.forEach((element) {
      children.add(
        new MyExpansionTile(element['did'], element['dname']),
      );
    });
    return children;
  }

  @override
  Widget build(BuildContext context) {
    return new ListView(
      children: _getChildren(),
    );
  }
}

class MyExpansionTile extends StatefulWidget {
  final int did;
  final String name;
  MyExpansionTile(this.did, this.name);
  @override
  State createState() => new MyExpansionTileState();
}

class MyExpansionTileState extends State<MyExpansionTile> {
  PageStorageKey _key;
  Future<http.Response> _responseFuture;

  @override
  void initState() {
    super.initState();
    _responseFuture =
        http.get('http://174.138.61.246:8080/support/dcreasons/${widget.did}');
  }

  @override
  Widget build(BuildContext context) {
    _key = new PageStorageKey('${widget.did}');
    return new ExpansionTile(
      key: _key,
      title: new Text(widget.name),
      children: <Widget>[
        new FutureBuilder(
          future: _responseFuture,
          builder:
              (BuildContext context, AsyncSnapshot<http.Response> response) {
            if (!response.hasData) {
              return const Center(
                child: const Text('Loading...'),
              );
            } else if (response.data.statusCode != 200) {
              return const Center(
                child: const Text('Error loading data'),
              );
            } else {
              List<dynamic> json = JSON.decode(response.data.body);
              List<Widget> reasonList = [];
              json.forEach((element) {
                reasonList.add(new ListTile(
                  dense: true,
                  title: new Text(element['reason']),
                ));
              });
              return new Column(children: reasonList);
            }
          },
        )
      ],
    );
  }
}

这篇关于颤振动态扩展的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！