flutter - 如何使用Dissmissable从itembuilder中删除项目，并且该项目来自Firestore？

Question

  @override
      Widget build(BuildContext context) {
        final textTheme = Theme.of(context).textTheme;
        return Scaffold(
          body: StreamBuilder<QuerySnapshot>(
            stream: Firestore.instance
                .collection('users')
                .document(widget.uid)
                .collection('lists')
                .snapshots(),
            builder: (context, snapshot) {
              return !snapshot.hasData
                  ? Center(child: CircularProgressIndicator())
                  : ListView.builder(
                      itemCount: snapshot.data.documents.length,
                      itemBuilder: (context, index) {
                        DocumentSnapshot data = snapshot.data.documents[index];
                        final list = snapshot.data.documents;
                        return Dismissible(
                          // Dismissed function
                          key: UniqueKey(),
                          onDismissed: (DismissDirection direction) {
                            setState(() {
    
                              // This is where I would like to remove the element
                              // snapshot.data.remove(index);
                              
                            });
                          },
                          secondaryBackground: Container(
                            child: Center(
                              child: Text('Delete',
                                  style: TextStyle(color: Colors.white),
                                  textAlign: TextAlign.start),
                            ),
                            color: Colors.red,
                          ),
                          background: Container(),
                          child: Card(
                            child: Center(
                              child: new Container(
                                padding: new EdgeInsets.all(32.0),
                                child: new Column(
                                  children: <Widget>[
                                    new Text(data['listName']),
                                    new Text(data['Description'])
                                  ],
                                ),
                              ),
                            ),
                          ),
                          direction: DismissDirection.endToStart,
                        );
                      },
                    );
            },
          ),

整个目标是使卡片元素消失并从Firestore中删除该项目。

我考虑过将每个项目放入 map 中，然后根据 map 构建卡片。我宁愿不那样做。

感谢您的帮助，希望我们可以一起解决这个问题:)
先感谢您!

Answer 1

首先通过以下操作获取文档引用:
对此进行迭代:snapshot.data.documents然后snapshot.data.documents[i].documentID然后这个:

onDismissed: (direction) async {
    await Firestore.instance.runTransaction(
      (transaction) async {
        await transaction.delete(your doc ref here);
      },
    );
  },