画像がまとまって、表示されてしまうので、一枚ずつ表示したいのですが、そのやり方がわからない状態にいます。

Question

私は、flutterでGridViewを使った画像一覧ページを作っています。しかし、画像がまとまった状態で表示されているので、見た目上では、全部同じ写真になっています。スクロールすれば、他の写真も表示される状態です。もしわかる方がいらしたら、やり方を教えて頂きたいです。

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now_list.dart

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_storage/firebase_storage.dart';
import 'package:image_picker/image_picker.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'dart:io';
import 'dart:math';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: NowList(),
    );
  }
}

class NowList extends StatefulWidget {
  @override _NowListState createState() => _NowListState();
}

class _NowListState extends State<NowList> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Firebase Storage'),
      ),
      body: GridView.builder(
             gridDelegate:
              SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 2),
          itemBuilder: (BuildContext context, int index) {
            return _buildBody(context);
          }
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: getImage,
        child: Icon(Icons.add_a_photo),
      ),
    );
  }

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

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

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

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

    return Padding(
      key: ValueKey(record.title),
      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
      child: Container(
        decoration: BoxDecoration(
          border: Border.all(color: Colors.grey),
          borderRadius: BorderRadius.circular(5.0),
        ),
        child: ListTile(
          title: Column(
            children: <Widget>[
              Image.network(record.imageURL),
            ],
          ),
        ),
      ),
    );
  }

  Future getImage() async {
    // Get image from gallery.
    var image = await ImagePicker.pickImage(source: ImageSource.gallery);
    _uploadImageToFirebase(image);
  }

  Future<void> _uploadImageToFirebase(File image) async {
    try {
      // Make random image name.
      int randomNumber = Random().nextInt(100000);
      String imageLocation = 'images/image${randomNumber}.jpg';

      // Upload image to firebase.
      final StorageReference storageReference = FirebaseStorage().ref().child(imageLocation);
      final StorageUploadTask uploadTask = storageReference.putFile(image);
      await uploadTask.onComplete;
      _addPathToDatabase(imageLocation);
    }catch(e){
      print(e.message);
    }
  }

  Future<void> _addPathToDatabase(String text) async {
    try {
      // Get image URL from firebase
      final ref = FirebaseStorage().ref().child(text);
      var imageString = await ref.getDownloadURL();

      // Add location and url to database
      await Firestore.instance.collection('books').document().setData({'imageURL':imageString , 'title':text});
    }catch(e){
      print(e.message);
      showDialog(
          context: context,
          builder: (context) {
            return AlertDialog(
              content: Text(e.message),
            );
          }
      );
    }
  }
}

class Record {
  final String title;
  final String imageURL;
  final DocumentReference reference;

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

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

  @override
  String toString() => "Record<$title:$imageURL>";
}