Flutter Voting App main.dart

main.dart

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

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Votes',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() {
    return _MyHomePageState();
  }
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(centerTitle: true, title: Text('Votes')),
      body: _buildBody(context),
    );
  }

  Widget _buildBody(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: Firestore.instance
          .collection('candidate')
          .orderBy('votes', descending: true)
          .orderBy('name')
          .snapshots(),
      builder: (context, snapshot) {
        if (!snapshot.hasData) return LinearProgressIndicator();

        return _buildList(context, snapshot.data.documents);
      },
    );
  }

  Widget _buildList(BuildContext context, List<DocumentSnapshot> snapshot) {
    String topElement = snapshot.elementAt(0).data.values.elementAt(0);
    return ListView(
      padding: const EdgeInsets.only(top: 20.0),
      children: snapshot
          .map((data) => _buildListItem(context, data, topElement))
          .toList(),
    );
  }

  Widget _buildListItem(
      BuildContext context, DocumentSnapshot data, String topElement) {
    final record = Record.fromSnapshot(data);

    return Padding(
      key: ValueKey(record.name),
      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
      child: Container(
        decoration: BoxDecoration(
          border: record.name == topElement
              ? Border.all(color: Colors.grey)
              : Border.all(color: Colors.lightGreen),
          color: record.name == topElement ? Colors.lightGreen : Colors.white,
          borderRadius: BorderRadius.circular(5.0),
        ),
        child: ListTile(
          title: Text(
            record.name,
            style: new TextStyle(fontSize: 22.0, fontWeight: FontWeight.bold),
          ),
          trailing: Text(
            record.votes.toString(),
            style: new TextStyle(fontSize: 22.0, fontWeight: FontWeight.bold),
          ),
          onTap: () => record.reference.updateData({'votes': record.votes + 1}),
        ),
      ),
    );
  }
}

class Record {
  final String name;
  final int votes;
  final DocumentReference reference;

  Record.fromMap(Map<String, dynamic> map, {this.reference})
      : assert(map['name'] != null),
        assert(map['votes'] != null),
        name = map['name'],
        votes = map['votes'];

  Record.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(snapshot.data, reference: snapshot.reference);

  @override
  String toString() => "Record<$name:$votes>";
}

Wow

hello