小编jds*_*flk的帖子

我想在我的 Flutter 应用程序中显示 SnackBar。我已阅读文档并复制它：\n
我的脚手架主体：

Widget build(BuildContext context) {\n    return WillPopScope(\n      onWillPop: () async => false,\n      child: Scaffold(\n        appBar: AppBar(\n          centerTitle: true,\n          title: Text("Oszt\xc3\xa1lyok"),\n          leading: Padding(\n              padding: const EdgeInsets.only(left: 5.0),\n              child: IconButton(\n                  icon: Icon(Icons.exit_to_app, color: Colors.white70),\n                  onPressed: () {\n                    authService.signOut();\n                    authService.loggedIn = false;\n                    Navigator.push(\n                        context,\n                        MaterialPageRoute(\n                            builder: (context) => GoogleSignUp()));\n                  })),\n          actions: <Widget>[\n            Padding(\n                padding: const EdgeInsets.only(right: 5.0),\n                child: Row(\n                  children: <Widget>[\n                    IconButton(\n                        icon: Icon(Icons.add_circle_outline,\n                            color: Colors.white70),\n                        onPressed: () {\n                          createPopup(context);\n                        }),\n//                    IconButton(\n//                        icon: Icon(Icons.search, color: Colors.black38),\n//                        onPressed: null),\n …

我有一个 Flutter 应用程序，它在 Listview.builder 的卡片上显示事件（存储在 Cloud Firestore 中）。我有一个特定的事件，足球。它有自己的特殊卡片。列表中可以有多个常规赛事，但只有一个足球赛事。我想在列表的顶部显示此足球赛事，作为第一张卡片。我怎样才能做到这一点？

到目前为止我的代码：

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:fociapp/model/events.dart';
import 'package:fociapp/ui/event_card.dart';

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
        stream: Firestore.instance.collection("events").snapshots(),
        builder: (BuildContext context, AsyncSnapshot snapshot) {
          return snapshot.hasData
              ? Container(
                  color: Colors.grey[850],
                  child: ListView.builder(
                    itemCount: snapshot.data.documents.length,
                    itemBuilder: (BuildContext context, int index) {
                      DocumentSnapshot events = snapshot.data.documents[index];
                      Event event = Event(
                          events["eventName"],
                          events["startTime"],
                          events["coverImageUrl"],
                          events["location"],
                          events["description"]);

                      return EventCard(event);
                    },
                  ),
                )
              : Center(
                  child: CircularProgressIndicator(),
                );
        });
  }
}