如何从防火墙数据创建列表

Question

我想从消防局数据中创建列表，以便在文本字段中添加建议/自动完成，有什么帮助吗？

示例列表：

  static final List<String> commodity = [
    'Banana',
    'Mango',
    'Orange',
  ];

从火药库通缉名单：

 static getSuggestion(String suggestion) async =>
      await FirebaseFirestore.instance
          .collection("QFS")
          .where('commodity', isEqualTo: suggestion)
          .get()
          .then((snap) {
        return snap.docs;
      });
}

我的全部代码：

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'package:flutter_typeahead/flutter_typeahead.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  var _selectedCommodity1;
  var _selectedCommodity2;
  TextEditingController commodityFiled1 = TextEditingController();
  TextEditingController commodityFiled2 = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Scaffold(
            appBar: AppBar(
              title: const Text("QFS"),
            ),
            body: Form(
                child: Container(
                    padding: const EdgeInsets.only(
                        top: 5, bottom: 10, right: 20, left: 20),
                    child: Column(children: [
                      TypeAheadFormField(
                        textFieldConfiguration: TextFieldConfiguration(
                            controller: commodityFiled1,
                            decoration: const InputDecoration(
                                labelText: 'Commodity1',
                                icon: Icon(
                                  Icons.receipt_rounded,
                                  color: Colors.black87,
                                ))),
                        suggestionsCallback: (pattern) {
                          return CommodityService.getSuggestions(pattern);
                        },
                        itemBuilder: (context, String suggestion) {
                          return ListTile(
                            title: Text(suggestion),
                          );
                        },
                        transitionBuilder:
                            (context, suggestionsBox, controller) {
                          return suggestionsBox;
                        },
                        onSuggestionSelected: (String suggestion) {
                          commodityFiled1.text = suggestion;
                        },
                        onSaved: (value) => _selectedCommodity1 = value!,
                      ),
                      TypeAheadFormField(
                        textFieldConfiguration: TextFieldConfiguration(
                            controller: commodityFiled2,
                            decoration: const InputDecoration(
                                labelText: 'Commodity2',
                                icon: Icon(
                                  Icons.receipt_rounded,
                                  color: Colors.black87,
                                ))),
                        suggestionsCallback: (pattern) {
                          return getSuggestion(pattern);
                        },
                        itemBuilder: (context, dynamic suggestion) {
                          return ListTile(
                            title: Text(suggestion),
                          );
                        },
                        transitionBuilder:
                            (context, suggestionsBox, controller) {
                          return suggestionsBox;
                        },
                        onSuggestionSelected: (dynamic suggestion) {
                          commodityFiled2.text = suggestion;
                        },
                        onSaved: (value) => _selectedCommodity2 = value!,
                      ),
                    ])))));
  }

  static getSuggestion(String suggestion) async =>
      await FirebaseFirestore.instance
          .collection("QFS")
          .where('commodity', isEqualTo: suggestion)
          .get()
          .then((snap) {
        return snap.docs;
      });
}

class CommodityService {
  static final List<String> commodity = [
    'Banana',
    'Mango',
    'Orange',
  ];

  static List<String> getSuggestions(String query) {
    List<String> matches = [];
    matches.addAll(commodity);
    matches.retainWhere((s) => s.toLowerCase().contains(query.toLowerCase()));
    return matches;
  }
}

Answer 1

Clarification：据我理解，您的集合中有文档，其中每个文档都具有属性commodity (类型为String__)，并且只想获取具有特定商品的文档。

打开GoogleFi还原数据库仪表板，检查哪些类型可以拥有您的集合文档。

单击Add document检查类型。

​

检查一下修复文档。

在snapshot.data内部，有docs (您收集的每个文档)。

代码来自文档：

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: _usersStream,
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError) {
          return Text('Something went wrong');
        }

        if (snapshot.connectionState == ConnectionState.waiting) {
          return Text("Loading");
        }

        return ListView(
          children: snapshot.data!.docs.map((DocumentSnapshot document) {
          Map<String, dynamic> data = document.data()! as Map<String, dynamic>;
            return ListTile(
              title: Text(data['full_name']),
              subtitle: Text(data['company']),
            );
          }).toList(),
        );
      },
    );
  }

上面的代码显示了如何将每个文档(类型为DocumentSnapshot)转换为JSON格式(可以用Map<String, dynamic>表示)。要访问您的字段commodity (键入String)，请放置此data['commodity']。对于doc id，您需要使用document.id进行访问，因为它不在document.data()方法中。

然后在suggestionCallback上(我读了“TypeAheadField of API接口”，您必须返回某种类型的列表(这是一个可链接的) (比如List<String>) )。

我以前从未试过这个颤振包，但我会编辑getSuggestion()

static Future<List<String>> getSuggestion(String suggestion) async =>
      return await FirebaseFirestore.instance
          .collection("QFS")
          .where('commodity', isEqualTo: suggestion)
          .get()
          .then((snap) {
            final docs = snap.data!.docs;

            return docs.map((DocumentSnapshot document) {
              Map<String, dynamic> data = document.data()! as Map<String, dynamic>;
              return data['<fieldname of your document, e.g., "country" or "commodity"'];

          }).toList(),
      });

在注释部分写出您的解决方案。