如何使用firestore绘制GridView卡组件背景

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

class MyGridView extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: FirebaseFirestore.instance.collection('cards').snapshots(),
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (snapshot.hasError) {
          return Text('Error: ${snapshot.error}');
        }

        if (snapshot.connectionState == ConnectionState.waiting) {
          return CircularProgressIndicator();
        }

        return GridView.builder(
          itemCount: snapshot.data.docs.length,
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: 2,
          ),
          itemBuilder: (BuildContext context, int index) {
            DocumentSnapshot card = snapshot.data.docs[index];
            Color backgroundColor = _getBackgroundColor(card);

            return Container(
              color: backgroundColor,
              child: Card(
                child: Text(card['title']),
              ),
            );
          },
        );
      },
    );
  }

  Color _getBackgroundColor(DocumentSnapshot card) {
    // 根据卡片的数据来决定背景颜色
    // 这里可以根据你的需求自定义逻辑
    // 例如，可以根据卡片的类型、状态等来设置不同的背景颜色
    return Colors.blue;
  }
}