Get Flutter FireStore Data

file.dart

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

class DisplayCollection extends StatefulWidget {
  @override
  _DisplayCollectionState createState() => _DisplayCollectionState();
}

class _DisplayCollectionState extends State<DisplayCollection> {
  final Ref = Firestore.instance.collection("Countries");

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Collection-Countries from Firebase"),
      ),
      body: Column(
        children: <Widget>[
          StreamBuilder(
            stream: Ref.snapshots(),
            builder: (context, AsyncSnapshot<QuerySnapshot> snapshot) {
              if (snapshot.hasData) {
                return Container(
                  height: 600,
                  child: ListView.builder(
                      itemCount: snapshot.data.documents.length,
                      itemBuilder: (context, index) {
                        return Container(
                          height: 100,
                          child: Card(
                            child: Column(
                              crossAxisAlignment: CrossAxisAlignment.start,
                              children: <Widget>[
                                Text(
                                  snapshot.data.documents[index]
                                      .data['CountryName'],
                                  style: TextStyle(
                                      fontSize: 25,
                                      fontWeight: FontWeight.bold),
                                ),
                                Text(
                                  snapshot.data.documents[index]
                                      .data['CapitalName'],
                                  style: TextStyle(
                                      fontSize: 20,
                                      fontWeight: FontWeight.w700),
                                ),
                              ],
                            ),
                          ),
                        );
                      }),
                );
              } else if (snapshot.hasError) {
                return Text(snapshot.error.toString());
              } else {
                return CircularProgressIndicator();
              }
            },
          ),
        ],
      ),
    );
  }
}